View source for Nen | Hunterpedia

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{{Hunterpedia:Item
|image = [[File:Nen_Diagram.png|250px]]
|name = Nen
|kanji = 念
|kana = ネン
|romaji = ''Nen''
|classification = Technique for (Supernatural) Use/Control of Life Energy{{Tt|*|Nen can also be defined/classified as 'an aura-based power' (as concisely put by Gon in Chapter 87) or, simply, control over aura.}}
|ability = Enables para-psychological/supernatural-like powers and abilities
|used by = [[Hunter Association|Hunters]] <br /> Various
|manga debut = [[Chapter 26]] (Used by [[Illumi Zoldyck|Illumi]]) <br /> [[Chapter 46]] (Term) <br /> [[Chapter 47]] (Concept)
|anime debut = [[Episode 15 (1999)]] (Used by [[Hisoka Morow|Hisoka]]) <br /> [[Episode 38 (1999)]] (Term & Concept)
----
[[Episode 15 (2011)]] (Used by Illumi) <br /> [[Episode 27 (2011)]] (Term) <br /> [[Episode 28 (2011)]] (Concept)}}
'''Nen''' ({{Ruby|念|ネン}} or ネン, ''Nen''—lit. "Sense";<ref name="chap80">Hunter × Hunter - Volume 9, Chapter 80</ref>{{Tt|*|Or, also literally, 'Idea', 'Thought', or 'Feeling'.}} "Mind Force" in the Viz transl.)<ref name="chap46">Hunter × Hunter - Volume 6, Chapter 46</ref> is one of the defining features of the manga [[Hunter × Hunter]] by [[Yoshihiro Togashi]]. It is a technique that allows a living being to use and manipulate their own life energy (known as '''aura''').<ref name="chap47">Hunter × Hunter - Volume 6, Chapter 47</ref> The term "Nen" can also be used in conversation to refer to aura. A person capable of utilizing Nen is colloquially referred to as a "Nen user" ({{Furigana|能|のう|力|りょく|者|しゃ}}, ''nōryokusha''—lit. "ability person"), while those who cannot go by the name of "non-users" ({{Furigana|一|いっ|般|ぱん|人|じん}}, ''ippanjin''—lit. "ordinary person").<ref name="chap361">Hunter × Hunter - Volume 35, Chapter 361</ref> Because one can craft a great variety of [[wikipedia:Parapsychology|para-psychological abilities]] through Nen, it is considered a dangerous power that is kept hidden from the public at large<ref name="chap60">Hunter × Hunter - Volume 7, Chapter 60</ref> to maintain balance in society.<ref name="chap377">Hunter × Hunter - Volume 36, Chapter 377</ref>

==Nen and Aura==
===Aura Nodes and Awakening===
[[File:AuraExplained.jpg|thumb|left|200px|Nen teaches one to control their own aura flow and utilize the energy]]

'''Aura''' (オーラ, ''Ōra'') is the life energy produced by all living bodies vital for survival. Aura from all parts of the body has a tendency to flow together, producing one mass of energy. This happens without the individual's awareness, typically resulting in a slow leak of aura continually escaping the body<ref name="chap47" /> and stemming up and off the top of the head.<ref name="chap372">Hunter × Hunter - Volume 36, Chapter 372</ref> The pores or points on the body from which aura flows out from are called "'''Aura Nodes'''" ({{Furigana|精|しょう|孔|こう}}, ''Shōkō''). In normal conditions, aura leaks away constantly without exceedingly harmful consequences; however, if someone whose Aura Nodes are fully open does not attempt to close them or control the flow of their aura, they will soon grow so fatigued they will be unable to stand<ref name="chap48">Hunter × Hunter - Volume 6, Chapter 48</ref> or even lose consciousness.<ref name="chap209">Hunter × Hunter - Volume 20, Chapter 209</ref> Grave wounds such as mutilations can disrupt the flow of aura in the affected body part and even stop it altogether.<ref>Hunter × Hunter - Volume 34, Chapter 356</ref> Controlling one's Aura Nodes is the first step to becoming a Nen user.

Only someone whose Aura Nodes located in the eyes are opened can see aura,<ref name="chap48" /> whose normal leakage looks similar to water vapor from a kettle. Nonetheless, sensitive individuals can feel its presence without being aware of its existence. It has been described as feeling like a warm, viscous fluid at rest,<ref name="chap48" /> whereas powerful, refined auras produce a sensation that feels akin to needles pricking into the skin.<ref>Hunter × Hunter - Volume 21, Chapter 215</ref> Hostile aura generates extremely unpleasant sensations, which can cause a non-user to halt in their tracks and be unable to walk towards the source as if a wall had been erected in front of them.<ref name="chap48" /> Since every living being emits aura subconsciously, learning to sense aura is a useful skill for those tracking living things or hunting non-living things infused with aura. An experienced user of Nen can judge the location and relative strength of their opponents through reading the output of their aura.<ref>Hunter × Hunter - Volume 31, Chapter 326</ref> On the other hand, skilled Nen users can also regulate the flow of their aura so they appear to be beginners or regular individuals.<ref name="chap372" />

===Learning Nen and Initiation===
[[File:Wing initiating Gon and Killua to Nen.png|thumb|right|250px|Wing initiating Gon and Killua to Nen]]

A student learning Nen trains to manually open and close their Aura Nodes so that they can control the flow of their aura. One typically learns this process slowly and gradually through meditation. There is a second method, colloquially called '''Initiation''' ({{Furigana|洗|せん|礼|れい}}, ''Senrei''—lit. "Baptism"), achieved by forcing the Aura Nodes to open via an influx of aura.<ref name="chap48" /> Despite being much quicker, this method is typically frowned upon by Nen instructors due to the danger it poses to the student if the user is inexperienced or has malicious intent,<ref name="chap48" /> and it is not considered a standard teaching method.<ref name="chap368">Hunter × Hunter - Volume 35, Chapter 368</ref> It is referred to as an "attack" to convey the taboo on it, which is due to the fact that non-users who awaken this way without having received an appropriate amount of training might take damage from the process or suffer from exhaustion for a long time due to being unable to control the aura leakage in all<ref name="chap388">Hunter × Hunter, Chapter 388</ref> but the rarest cases.<ref name="chap48" />

Initiation via physically attacking another is common practice at the [[Heavens Arena]] when a non-user reaches the 200<sup>th</sup> floor and typically results in injury, permanent disability, or even death.<ref name="chap48" /> Nonetheless, this is by no means the only way to force or, more appropriately, semi-force, the Aura Nodes open: the same result can be achieved through "indirect attacks", non-violent or even beneficial uses of aura on a non-user, such as through healing, lending, or absolutely first-class Manipulation abilities.<ref name="chap388" /> Experienced Nen users can open a student's Aura Nodes simply by performing ''Hatsu'' on them.<ref name="chap48" />

A state of half-awakening exists in which an individual may be able to control their aura to a certain degree and release a larger amount than a normal person, but still have some of their Aura Nodes closed, which may result in their being unable to see aura. This state can be found in some victims of Manipulation Nen as well as in the bodyguards of [[Halkenburg Hui Guo Rou]], who reached it through the latter's [[Guardian Spirit Beast]].<ref name="chap372" />

===Progression and Potential===
While all living things posses aura and all humans (as well as possibly beings of other species) are able to master Nen, some excel at its usage more than others. What exactly factors into potential is for the most part a mystery, but it appears to be predominantly a congenital factor, since statistical estimations about its rarity can be made and evidence points against it changing over the course of one's life. The rubric of "potential" or "talent" entails both the maximum degree of mastery that one could achieve and the speed of one's learning, which seem to be directly proportional: the faster one learns, the higher their upper ceiling is assumed to be.<ref name="chap60" /><ref name="chap139">Hunter × Hunter - Volume 14, Chapter 139</ref> It is important to note that learning rate can have multiple meanings: [[Gon Freecss]] took more time than [[Killua Zoldyck]] to control the flow of his aura,<ref name="chap141">Hunter × Hunter - Volume 15, Chapter 141</ref> but he was able to discover multiple Nen techniques on his own,<ref name="chap50">Hunter × Hunter - Volume 6, Chapter 50</ref><ref name="chap140">Hunter × Hunter - Volume 15, Chapter 140</ref> and his potential was never implied to be lower than Killua's. The circumstances of one's growth can also combine with one's talent to facilitate learning,<ref name="chap50" /> further highlighting that rate of progression should not be taken as a perfectly transparent indicator of one's maximum potential, although in general it can be considered fairly reliable. There is an introductory exercise that can reveal a person's talent,<ref name="chap370">Hunter × Hunter - Volume 35, Chapter 370</ref> but there are also Nen users with the ability to estimate another's potential at a glance.<ref>Hunter × Hunter - Volume 2, Chapter 9</ref><ref>Hunter × Hunter - Volume 13, Chapter 122</ref><ref>Hunter × Hunter - Volume 23, Chapter 242</ref>

There might be anecdotal evidence in support of talent for Nen depending at least in part on genetics and/or family history, since [[Ging Freecss|the]] [[Silva Zoldyck|fathers]] of Gon and Killua, whose potential can be found only in one person out of 10,000,000,<ref name="chap60" /> are both vastly above-average Nen users, and [[Tserriednich Hui Guo Rou]], who was called a genius,<ref name="chap366">Hunter × Hunter - Volume 35, Chapter 366</ref> descends from a lineage of hosts of parasitic Nen beasts and possibly Nen users.<ref name="chap349">Hunter × Hunter - Volume 33, Chapter 349</ref> On the other hand, body type and sex are unrelated to one's potential,<ref name="chap386">Hunter × Hunter, Chapter 386</ref> while it is possible, though not definitive, that age affects the speed of one's learning.<ref name="chap388" /><ref group="note">In [[Chapter 388]] Kurapika commended [[Maor]] for the rate of his progression in spite of his age, but this might have been only a way to flatter him, as he had already done so in the past. If, however, there is truth to it, then age would indeed play a part in determining how quickly one can learn, though not necessarily the maximum degree of proficiency they can reach.</ref>

Of course, potential alone does not ensure that one will grow into a powerful Nen user, with one's regimen of training being fundamental in this regard. Furthermore, talent does not guarantee that one will progress in all areas of Nen with the same ease, as the comparison between Gon and Killua revealed. One's growth can also be stunted by training the wrong Nen categories.<ref name="chap54">Hunter × Hunter - Volume 6, Chapter 54</ref><ref name="chap60" /><ref name="chap362">Hunter × Hunter - Volume 35, Chapter 362</ref>

===Nen of the Flame===
'''Nen of the Flame'''<ref group="note">"Nen of the Flame" is an unofficial name given to this more theoretical discipline to reflect the difference in the ''kanji'' used for it and for Nen proper. In the Viz translation of [[Chapter 51]], Wing refers to the Ten principle as "the Flame one".</ref> ({{Ruby|燃|ネン}} or ネン, ''Nen''—lit. "Burn"{{Tt|*|Or, also literally, 'Blaze' or 'Glow'.}}; "Flame" in the Viz translation) is sometimes used in [[Shingen-ryu]] ''kung fu'' as a precursor to learning the actual Nen. They are mental exercises akin to meditation that strengthen one's force of will. Regular practice can smooth the flow of one's aura. The Four Exercises of Nen of the Flame are as follows:
* '''Ten''' ({{Ruby|点|テン}}, ''Ten''; "Point"): Focus the mind, reflect upon the self and determine the goal.
* '''Zetsu''' ({{Ruby|舌|ゼツ}}, ''Zetsu''; "Tongue"): Put it into words.
* '''Ren''' ({{Ruby|錬|レン}}, ''Ren''; "Temper"): Intensify your will.
* '''Hatsu''' ({{Ruby|発|ハツ}}, ''Hatsu''; "Release"): Put it to action.<ref name="chap46" />

Upon his introduction, Wing taught Killua and Gon the Nen of the Flame as a fake sense of Nen that focuses mostly on meditation and on one's self.<ref name="chap46" /> Not all steps of this method directly manipulate aura and most have no visible effect; however, after Gon was injured by Gido and forbidden to use Nen for two months to recover by Wing, both Gon and Killua practiced this method,<ref name="chap50" /> and in fact made it more natural for them to use regular Nen. Given that Nen is linked to emotions and mental state, this method can be particularly useful to train Nen without aura, although normal use of the technique is usually preferred.<ref name="chap56">Hunter × Hunter - Volume 7, Chapter 56</ref>

==Properties of Nen==
===Nen and Emotion===
[[File:Hisoka episode 16.PNG|thumb|left|200px|[[Yoshihiro Togashi|Togashi]] typically indicates this effect through his shading]]

Although the production of aura is unconscious and constant by all living beings, it is not only life energy. Aura carries with it the desires and emotions of the one who deploys it, which is what allows for Nen to have an incredible versatility to those who develop their skill at using it,<ref name="chap56" /> and also heavily influenced by mental condition and emotional state.<ref name="chap83">Hunter × Hunter - Volume 9, Chapter 83</ref> A basic application of this phenomenon is that one can channel their aggression or malice into their aura and deploy it towards another person (i.e. bloodlust). The antagonized will then be able to feel that bloodlust as if it were physically palpable; if unable to keep it from their own body by deploying their own Nen, he/she may be psychologically as well as physically harmed by it.<ref name="chap48" /> In certain instances, emotional factors may even lead to one exceeding their current ceiling. This could potentially prove advantageous, but in general using one's powers beyond their capacity entails a great risk and will ultimately cause strain.<ref name="chap83" />

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===Post-Mortem Nen===
The death of a Nen user does not necessarily result in the cessation of their abilities; on the contrary, it may cause pre-existing abilities to become even more powerful. The most common reason for this phenomenon to occur is the ability of the dying user while harboring a strong grudge will cause their Nen to seek out the object of their hatred and cling to it. This makes curse-type abilities much more difficult to remove, to the point that fewer than ten Exorcists in the whole world were deemed capable of lifting a curse left by the deceased.<ref name="chap120" />

[[File:131 - Terpsichora Neferpitou.png|thumb|right|250px|'''Terpsichora''' manipulates Neferpitou's headless corpse]]

It seems that other than hatred, any powerful enough emotion can result in post-mortem Nen: Neferpitou’s '''Terpsichora''' took control of their beheaded corpse out of loyalty to the King, even though the [[Royal Guards|Royal Guard]] did not consciously perceive Gon as a threat due to believing him to have given up all of his potential to kill them.<ref name="chap306">Hunter × Hunter - Volume 29, Chapter 306</ref> Some Nen users go as far as to make their own death an activation requirement, which, despite their demise being only temporary and programmed, still grants their abilities greater power than normal.<ref name="chap357">Hunter × Hunter - Volume 34, Chapter 357</ref><ref name="chap373" /> Death can also cause Nen abilities to linger even if their doing so violates the conditions of other abilities: a notable example is '''The Sun and Moon''', which remained in Chrollo’s book despite the creator passing away and, if applied to a conjured object, the object cannot be dispelled until the marks explode,<ref name="chap354">Hunter × Hunter - Volume 34, Chapter 354</ref> both of which are in explicit contradictions of conditions of the Spider’s '''Skill Hunter'''.<ref name="chap352">Hunter × Hunter - Volume 34, Chapter 352</ref>

===Nen and Nature===
Affinity with nature is connected to sensitivity for aura.<ref name="chap225">Hunter × Hunter - Volume 22, Chapter 225</ref> Wild animals are more perceptive in that regard than humans, and may learn ''Zetsu'' spontaneously.<ref name="chap191">Hunter × Hunter - Volume 19, Chapter 191</ref><ref>Hunter × Hunter - Volume 22, Chapter 233</ref> However, only humans and certain Magical Beasts have displayed the ability to open their Aura Nodes and use Nen. Honing one's Nen abilities has the side effect of attuning them with nature to a greater degree, enabling the user to detect sounds, scents, and tracks non-users would miss, as well as to attract wildlife, this has led to the belief that good Hunters are well-liked by animals.<ref name="chap186">Hunter × Hunter - Volume 18, Chapter 186</ref>

[[File:118 - Youpi powers up.png|thumb|left|250px|Youpi, who has no human genes, releasing his aura]]

After the [[Chimera Ant Queen]] who came to the Human World from the [[Dark Continent]] began to feed on humans, she spawned offspring with the innate ability to see aura, namely some Officers<ref name="chap190">Hunter × Hunter - Volume 19, Chapter 190</ref> and the [[Squadron Leaders]].<ref name="chap190" /><ref name="chap197">Hunter × Hunter - Volume 19, Chapter 197</ref> The Royal Guards<ref name="chap197" /> and the [[Meruem|King]]<ref name="chap216">Hunter × Hunter - Volume 21, Chapter 216</ref> were able to freely control their Aura Nodes and flow from birth. [[Menthuthuyoupi]] developed Nen abilities despite having no human genes, only those of a Magical Beast.<ref>Hunter × Hunter - Volume 25, Chapter 266</ref> [[Nanika]]'s wish-granting power might also work through aura;<ref>Hunter × Hunter - Volume 29, Chapter 333</ref><ref>Hunter × Hunter - Volume 29, Chapter 334</ref> if it does, it might mean that it is a Nen ability of utterly unprecedented power and scope.

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===The Unknown===
Though Nen is influenced by one's mental condition and emotional state, it is difficult to judge exactly to what extent these factors affect Nen. Biscuit Krueger became capable of altering her appearance without actively training for it, instead wishing for her body to change for years, which caused the changes to manifest little by little.<ref name="chap375">Hunter × Hunter - Volume 36, Chapter 375</ref> It is also unclear just how subjective and dependent upon one's capacity to assess risk certain ability conditions and Limitations are.

[[File:Inscription anime.jpg|thumb|right|250px|The mysterious inscription on Ging's metal box]]

Another mystery is the exact relation between Nen, the [[Divine Script]] and a seemingly different type of [[inscription]]. The Divine Script has the power to strengthen the Nen abilities of the one who drew it, provided it is charged with their aura and the user remains in its proximity;<ref>Hunter × Hunter - Volume 16, Chapter 160</ref> the latter inscription was noted to have similar properties to Nen and the ability to reinforce whatever it is applied to, but cause it to break as soon as it comes in contact with aura.<ref name="chap65">Hunter × Hunter - Volume 8, Chapter 65</ref> Interestingly, it might have been used on a handcuff designed to restrain a Nen user.<ref>Hunter × Hunter - Volume 33, Chapter 342</ref> Just like the Divine Script, this inscription appears to require aura to function.<ref name="chap56" />

==Nen in Society==
Nen is a power unknown to the public at large, with only a minority of persons being capable of using it or even privy to its existence. Reports of incidents involving Nen are often misleading,<ref name="chap357" /> in large part probably because ignorance of its existence necessarily leads to incorrect assumptions.

Some non-users who hear of Nen believe it to be no more than a mental technique to gain a little boost in physical abilities by accessing the dormant power in one's body.<ref name="chap375" /> For their part, Nen users tend to avoid attracting too much attention in order to prevent society from spiraling into chaos.<ref name="chap377" />

===Nen and the State===
It is unknown if leaders of countries or even of international entities (such as the [[V6]]) know about Nen. The high-ranking members of the [[Kakin Empire]] army are completely unaware of it,<ref>Hunter × Hunter - Volume 36, Chapter 380</ref> although Prince [[Benjamin Hui Guo Rou]], the Military Deputy Adviser, can use Nen and commands a squad of Nen users.<ref name="chap363">Hunter × Hunter - Volume 35, Chapter 363</ref> The [[Nasubi Hui Guo Rou|King]] himself might be a Nen user, although awareness of the existence of Nen could be tied to the [[Guardian Spirit Beast#The Seed Urn|history of the family]] rather than be knowledge that is shared with the head of state because of their position. In the [[Republic of East Gorteau]] a small group of [[East Gorteau Nen-using Soldier|Nen-using soldiers]] guarded the [[Royal Palace of East Gorteau|royal palace]].<ref name="chap216" />

In ordinary circumstances, Nen is not admissible as evidence in judicial proceedings.<ref name="chap372" />

===Nen and the Hunter Association===
Acquiring control over one's aura flow is the final step to becoming a professional Hunter,<ref name="chap60" /> as per the second [[Hunter Bylaws|Hunter Bylaw]].<ref>Hunter × Hunter - Volume 29, Chapter 331</ref> According to [[Wing]], this is because Hunters need to be deterrents for the crime. However, since Nen could be extremely disruptive to society, it was deemed unsafe to include it as a publicly-known criterion and an official part of the [[Hunter Exam]], and is therefore known within the [[Hunter Association]] as the "[[Hunter Association#The Secret Hunter Exam|Secret Hunter Exam]]".<ref name="chap60" /> Accordingly, many high-profile jobs contracted to the Hunter Association list knowledge of Nen as a minimum requirement.<ref>Hunter × Hunter - Volume 6, Chapter 51</ref> A licensed Hunter may not reveal the existence of Nen to those who do not know about it, although it is possible to relay this information in times of emergency.<ref name="chap359">Hunter × Hunter - Volume 34, Chapter 359</ref>

Many Hunters are proficient Nen users, with [[Isaac Netero]], the 12<sup>th</sup> Chairman of the Hunter Association,<ref>Hunter × Hunter - Volume 30, Chapter 320</ref> being revered as the world's most powerful Nen master in his prime.<ref name="chap202">Hunter × Hunter - Volume 20, Chapter 202</ref> Since mastery of Nen leads to attunement with nature,<ref name="chap225" /> this has led to the credence that good Hunters are well-liked by animals.<ref name="chap186" />

===Nen and Entertainment===
====Heavens Arena====
Curiously, Nen abilities are freely and regularly displayed in front of an audience at the [[Heavens Arena]], and not only are they common knowledge from the 200<sup>th</sup> floor upward, fighters on that floor will brutally "initiate" anyone who reaches it without knowing Nen.<ref name="chap48" /> Hunters who participate in the matches and showcase Nen abilities seem to face no consequences despite the ban put in place by the Hunter Association, nor does it appear as though there are repercussions for openly mentioning the system.<ref name="chap62">Hunter × Hunter - Volume 7, Chapter 62</ref><ref group="note">Gon and Hisoka, Hunters both, were able to participate in matches and use Nen abilities despite being Hunters, with no warning or ill consequences. In [[Chapter 62]] Hisoka even openly mentions the six Nen categories.</ref> On the other hand, the audience is in the vast majority of cases ignorant of Nen and confused by the supernatural powers they see. The commentators themselves appear to have no knowledge of Nen,<ref name="chap53">Hunter × Hunter - Volume 6, Chapter 53</ref> not even the ones overseeing [[Floor Masters|Floor Master]] matches.<ref name="chap351">Hunter × Hunter - Volume 34, Chapter 351</ref>

====Greed Island====
[[Greed Island]] is a video game created by [[Ging Freecss]] and [[G.I. Game Masters|other 10 Nen users]].<ref name="chap184">Hunter × Hunter - Volume 18, Chapter 184</ref> In 1987 a total of 100 copies was released by Marilyn Inc. Originally marketed as being for Hunters only,<ref name="chap69">Hunter × Hunter - Volume 8, Chapter 69</ref> the game can be played by any Nen user. It teleports the player<ref name="chap134">Hunter × Hunter - Volume 14, Chapter 134</ref> to a privately owned island which does not appear on any map.<ref name="chap144">Hunter × Hunter - Volume 15, Chapter 144</ref> With the exception of the players, the island is populated almost exclusively by NPCs, which, like all the miraculous items in the game, are created with Nen.<ref name="chap134" /> Upon hearing of cards that could [[Angel's Breath (G.I card)|cure all ills]] and [[Witch's Rejuvenation Potion (G.I card)|restore one's youth]], billionnaire [[Battera]] used his influence and wealth to hide the details of the game from the public and hired scores of players to clear it in an attempt to save [[Battera's Lover|the woman he loved]].<ref name="chap174">Hunter × Hunter - Volume 17, Chapter 174</ref>

====Pip-Play====
'''Pip-Play''' (イボクリ, ''Ibokuri'') is a dexterity challenge using aura. One creates a "pip" out of their aura on their hand and makes it move in a linear fashion. The difficulty of the game can be increased by adding a second hand, creating more pips, changing their size and shape, and having them move at different speeds and in different directions. Pip-Play can be considered a challenge of one's Nen dexterity but overall it's considered a useless talent and does not affect abilities.<ref>Hunter × Hunter - Volume 33, Chapter 346</ref> Since the game involves changing the shape of one's aura, it is possible that it is affected by the user's Transmutation skills.

Players:
* [[Ging Freecss]]
* [[Usamen]]

===Geniuses===
[[File:Geniuses Around The World.png|thumb|right|250px|Some of the world's most famous and influential people have naturally learned Nen]]

Nen is like any other skill, in that there are those who can learn it faster than others. Some are able to discover and learn to manipulate their aura on their own without having formally learned it. These individuals are typically known as "geniuses", "psychics", or "superhumans" to the public. This can be anything from inadvertently being able to use the basic techniques of Nen<ref name="chap48" /> or unconsciously developing a unique Nen ability that can be used without really understanding how or why one is able to do so. Typically, geniuses of Nen are exceptional artisans in their own fields and their abilities are related to them.<ref name="chap85">Hunter × Hunter - Volume 10, Chapter 85</ref>

Notable geniuses within the series include:
* [[Neon Nostrade]], the fortune-teller.
* [[Benny Delon]], the mass-murderer and blacksmith.<ref name="chap85" />
* [[Mukatolini]], the lithographer.<ref>Hunter × Hunter - Volume 10, Chapter 86</ref>
* [[Zepile]], the counterfeit artist.<ref>Hunter × Hunter - Volume 10, Chapter 87</ref>
* [[Komugi]], the [[Gungi]] world champion.<ref>Hunter × Hunter - Volume 24, Chapter 257</ref>

==Four Major Principles==
[[File:HorribleSubsHunterXHunter-30480pmkv snapshot 0043 20120506 094310.jpg|thumb|left|250px|The four major principles of Nen]]

In order to fully grasp Nen, one must first learn the '''Four Major Principles''' ({{Furigana|四|よん|大|たい|行|ぎょう}}, ''Yontaigyō''—lit. "Four Major Lines")<ref name="chap46" /> of the Shingen-ryu school of ''kung fu''. Everything else, including a practitioner of Nen's individual skills, is based on the basic manipulations of one's aura flow. The Four Major Principles, in order of study, are: '''Ten''', '''Zetsu''', '''Ren''', and '''Hatsu'''.<ref name="chap47" />

These basic techniques become second-nature to those experienced in Nen. For example, a beginner must learn to use ''Ten'' and concentrate to maintain it; whereas someone with experience will practically always be in a state of ''Ten'', even during sleep.<ref name="chap48" />

====Ten====
[[File:Gon Ten.png|thumb|right|200px|Gon using ''Ten'']]

Once a person has opened their Aura Nodes, they must learn to keep their aura from leaking away from their body. '''''Ten''''' ({{Ruby|纏|テン}}, ''Ten''; "Envelop"/"Shroud") is the process of keeping the nodes open, but also having aura flow through and around the body rather than away from it. Once maintained, it creates a shroud around the user that feels similar to standing in a lukewarm, viscous fluid. ''Ten'' maintains youthful vigor and reduces one's aging, since the energy powering the body no longer leaks away; one can keep the body from breaking down and deter the aging process.<ref name="chap47" /> ''Ten'' is the most basic defense against emotional Nen attacks,<ref name="chap47" /> and it also offers limited protection against physical attacks,<ref name="chap46" /> but hardly any when said attacks are enhanced with aura.<ref name="chap50" /> Through frequent meditation and practice, one can improve the quality of their ''Ten'' and even maintain it in their sleep.<ref name="chap48" /> Once it has been learned, it will never be forgotten, much like cycling and swimming.<ref name="chap56" /> Despite being the most elementary technique of all, ''Ten'' is also one of the most important, since, together with ''Ren'', it plays an instrumental role in determining the strength and smoothness of a Nen user's aura flow.<ref name="chap123" /><ref name="chap148">Hunter × Hunter - Volume 15, Chapter 148</ref>

====Zetsu====
[[File:Killua_Zetsu.jpg|thumb|left|250px|Killua using ''Zetsu'']]

While ''Ten'' allows a user to keep aura from leaking away from their body, '''''Zetsu''''' ({{Ruby|絶|ゼツ}}, ''Zetsu''; "Suppress"/"Null") stops the flow of aura from their body altogether. By closing all of their Aura Nodes, the user is able to halt all outflow of their aura like water from a valve, making their presence much harder or even impossible to sense.<ref name="chap47" /> Shutting off the nodes in their eyes prevents the user from being able to see aura,<ref name="chap222">Hunter × Hunter - Volume 21, Chapter 222</ref> but, since they are no longer surrounded by their own aura, they become more sensitive to the aura of others.<ref name="chap50" /> The enhancement in perception is such that ''Zetsu'' can counter ''In'', although it is not advised to employ it this way.<ref name="chap56" /> This technique is thus doubly useful when tracking another person, as not only it will make it easier to follow them, it will also prevent other users of Nen from noticing their pursuer. However, there are other ways to perceive a person hiding with ''Zetsu'': aside from the five senses being effective, particularly perceptive individuals are capable of detecting the gaze of another person, although they might not manage to discern the position and number of onlookers.<ref name="chap90">Hunter × Hunter - Volume 10, Chapter 90</ref> Furthermore, if ''Zetsu'' is utilized within a certain range from a Nen user, that Nen user might notice their presence disappearing, especially if the ''Zetsu'' user's aura is powerful.<ref>Hunter × Hunter - Volume 6, Chapter 52</ref> Despite the technique not affecting vision directly, activating ''Zetsu'' in front of someone else will give them the impression the user has turned transparent.<ref name="chap90" />

''Zetsu'' can also be used to relieve fatigue, since it forces the body's external layer of aura to be fully contained within.<ref name="chap47" /> However, for the same reason it can be dangerous due to it leaving the body defenseless against any aura attack. Even a weak attack enhanced with Nen could do massive damage.<ref name="chap50" /> Since even the thin protection offered by ''Ten'' is gone, a ''Zetsu'' user is particularly susceptible also to hostile emotional attacks,<ref name="chap361" /> resulting in their mind becoming as vulnerable as their body.

====Ren====
[[File:S7h2GC.jpg|thumb|right|250px|Gon, Killua, and Zushi using ''Ren'']]

'''''Ren''''' ({{Ruby|練|レン}}, ''Ren''; "Refine"/"Enhance") focuses on outputting a larger amount of aura than ''Ten'', projecting it outwards explosively.<ref name="chap47" /> This amplifies the user's physical strength and durability and provides a large pool of aura for any advanced techniques or individual skills they decide to use, albeit at the cost of expending said aura. One can train their ''Ren'' to extend its duration and increase the amount of aura at their disposal. It is said it takes one month to prolong one's ''Ren'' outside of combat by 10 minutes.<ref name="chap201">Hunter × Hunter - Volume 20, Chapter 201</ref> If ''Ten'' is considered purely defensive, ''Ren'' can be regarded as its offensive counterpart, although it also grants the user vastly enhanced defensive abilities.<ref>Hunter × Hunter - Volume 7, Chapter 58</ref> With the right timing, ''Ten'' can be used to contain the aura produced with ''Ren''.<ref name="chap57">Hunter × Hunter - Volume 7, Chapter 57</ref>

By tingeing one's ''Ren'' with hostility, a Nen user can exert what is colloquially referred to as "bloodlust". A prolonged emission of malicious ''Ren'' can induce uncontrollable dread in those who cannot use Nen, paralysis and if contrasted without ''Ten'', even death. On the other hand, a neutral ''Ren'' can rarely be felt by non-users.<ref name="chap47" /> Since ''Ren'' is a show of power, it can also intimidate other Nen users, as it offers an approximate measure of the user's raw strength;<ref name="chap121">Hunter × Hunter - Volume 13, Chapter 121</ref> in fact, by "show me your ''Ren''", Hunters generally mean they want to see the fruits of one's training, such as a Nen ability, rather than their ''Ren'' per se.<ref name="chap125">Hunter × Hunter - Volume 13, Chapter 125</ref> In most cases, ''Ren'' reflects the user's hostility without their control, and it can even leave faint traces in the environment after the Nen user has left the scene.<ref name="chap98">Hunter × Hunter - Volume 11, Chapter 98</ref>

====Hatsu====
[[File:Hunterxhunter 28 07x.jpg|thumb|left|250px|Wing using ''Hatsu'']]

'''''Hatsu''''' ({{Ruby|発|ハツ}}, ''Hatsu''; "Release"/"Act") is one's personal expression of Nen. Its qualities are influenced by but not restricted to the Nen user's natural Nen category, one of the six available. ''Hatsu'' is used to project one's aura to carry out a certain function, creating a special and unique paranormal ability<ref name="chap60" /> that is colloquially referred to as a "'''Nen ability'''" ({{Furigana|念|ネン|能|のう|力|りょく}}, ''Nen nōryoku''),<ref name="chap371">Hunter × Hunter - Volume 36, Chapter 371</ref> or simply "'''ability'''" ({{Furigana|能|のう|力|りょく}}, ''nōryoku'').<ref name="chap361" /><ref group="note">Although the term "'''Hatsu ability'''" is popular in the English-speaking fandom, that combination of terms was never used in the source material.</ref>

At first, ''Hatsu'' appears simply as a consequence of using ''Ren'' during Water Divination; however, it is more than a mere property of the latter, and it can be trained individually either through Water Divination itself, which however seems to only affect the user's natural category,<ref name="chap60" /> or by honing one's skills in a Nen category via specific exercises.<ref name="chap145">Hunter × Hunter - Volume 15, Chapter 145</ref> Once a certain level of skill has been attained, the student can attempt to create their personal Nen ability. Since they can have an immensely vast range of effects, Nen abilities may be recognized as any manifestation of one's Nen that cannot be ascribed to one of the basic or advanced techniques, although there are instances of Nen abilities being essentially applications of ''Ko'' (an advanced Nen technique which makes use of ''Hatsu'') with special conditions or restrictions.<ref name="chap141" /> A good Nen ability reflects a person's own character, regardless of its complexity; one can never truly master Nen if they only copy someone else's abilities.<ref name="chap56" />

==Advanced Techniques==
After acquiring a working command of the basics, a student is introduced to a series of advanced techniques that often combine and/or derive from the four Major Principles. These techniques expand the user's options in combat manifold, but they also consume more aura than the Four Major Principles.<ref name="chap140" />

====Gyo====
[[File:Zushi Gyo 2011.png|thumb|right|250px|Zushi using ''Gyo'']]

'''''Gyo''''' ({{Ruby|凝|ギョウ}}, ''Gyō''; "Focus") is an advanced application of ''Ren'' by which a Nen user concentrates a larger than normal portion of their aura into one specific body part. It increases the strength of that one body part, but leaves the rest of the body more vulnerable. ''Gyo'' is most often used in the eyes, allowing a Nen user to see aura and Nen constructs concealed with ''In''<ref name="chap56" /> as well as traces of aura so faint that they might go unnoticed otherwise.<ref name="chap85" />

An alternative version of this technique gathers only the aura naturally leaking from the body instead of the greater amount produced with ''Ren''. This application of ''Gyo'' can still increase the amount of aura in one select body part and thus its power, but the output is much lower than what is obtained through the regular technique.<ref name="chap124">Hunter × Hunter - Volume 13, Chapter 124</ref> It is unlikely this lower-consumption ''Gyo'' could counter ''In'', since Wing had all his students perform ''Ren'' to do so.<ref name="chap56" /> However, it has proven to suffice to see thin layers of aura<ref name="chap85" /><ref name="chap123">Hunter × Hunter - Volume 13, Chapter 123</ref> as well as to perform Water Divination correctly.<ref name="chap376" />

====In====
[[File:Uvogin in Chains.png|thumb|left|250px|Uvogin trapped within Kurapika's chains, concealed from view through ''In'']]

'''''In''''' ({{Ruby|隱|イン}}, ''In''; "Conceal") is an advanced form of ''Zetsu'' used to render one's aura imperceptible, effectively concealing it. Unlike ''Zetsu'', however, ''In'' does not stop the user's aura flow; instead, it hides it,<ref name="chap56" /> making it impossible to perceive with any of the five senses or extrasensorial perception. Hence, this technique is perfect for launching sneak attacks or laying traps, as it can conceal not only the user's presence,<ref name="chap82">Hunter × Hunter - Volume 9, Chapter 82</ref> but also Nen constructs generated with Transmutation,<ref name="chap56" /> or Conjuration.<ref name="chap82" />

''In'' can be countered by using ''Gyo'' in the eyes or through ''Zetsu''.<ref name="chap56" /> When ''In'' conceals part<ref name="chap55">Hunter × Hunter - Volume 7, Chapter 55</ref> (or even all)<ref name="chap56" /> of the user's aura output, experienced Nen users can divine their opponent is using it if little or no aura can be felt from them in circumstances which would normally require it, such as during combat.<ref name="chap55" />

====En====
[[File:EN_2011.png|thumb|right|250px|Nobunaga using ''En'']]

'''''En''''' ({{Ruby|円|エン}}, ''En''; "Circle") is an advanced application of ''Ten'' and ''Ren''.<ref name="chap94">Hunter × Hunter - Volume 11, Chapter 94</ref> In ''Ren'', aura usually envelops only a small amount of space around the user's body. ''En'' is when one extends their ''Ren'' so that their aura extends further than normal, then uses ''Ten'' at the same time to contain and give shape to that aura, normally a sphere. The minimum requirement is to extend one's aura to a radius of more than 2 meters (6.56168 feet) and hold it longer than 1 minute.<ref>Hunter × Hunter - Volume 23, Chapter 237</ref> Someone using ''En'' can feel the shape and movement of anything within the area covered by their aura, with the degree of awareness and finesse depending on their level of skill.<ref name="chap94" /> Nen users can be told apart from regular people due to their stronger reaction to the ''En'' user's aura.<ref>Hunter × Hunter - Volume 29, Chapter 308</ref>

Those who master ''En'' are typically able to extend it to a circle with a 50 meter (54 yard, 2 foot, 0.5052 inch) radius.<ref name="chap94" /> There are exceptions, however: [[Zeno Zoldyck]], one of the most powerful assassins alive, is able to extend his ''En'' up to a radius of 300 meters (328.084 yards),<ref name="chap98" /> while the [[Chimera Ants|Chimera Ant]] [[Neferpitou]] has an irregularly shaped ''En'' and can extend a tendril up to 2 kilometers (1 mile, 427 yards, and 8.0064 inches).<ref>Hunter × Hunter - Volume 24, Chapter 259</ref> The downside to this technique is that it is extremely tiring and draining for the Nen user to constantly deploy so much aura.<ref name="chap98" />

====Shu====
[[File:Gon Shu.png|thumb|left|180px|Gon using ''Shu'']]

'''''Shu''''' ({{Ruby|周|シュウ}}, ''Shū''; "Enfold") is an advanced application of ''Ten''. ''Shu'' allows a user of Nen to enshroud an object with their aura, allowing them to use that object as an extension of their own body. For example, one could use ''Shu'' to extend their ''Ten'' around a weapon, which would strengthen and protect it.<ref name="chap140" /> ''Shu'' can be combined with other techniques, such as ''Ko''.<ref name="chap145">Hunter × Hunter - Volume 15, Chapter 145</ref>

{{Clrl}}
====Ko====
[[File:Biscuit ko 2011.png|thumb|right|250px|Biscuit using ''Ko'']]

'''''Ko''''' ({{Ruby|硬|コウ}}, ''Kō''; "Temper") is a combination of ''Ten'', ''Zetsu'', ''Hatsu'', ''Ren'', and ''Gyo'' in which all of the user's aura is concentrated into one particular body part.<ref name="chap141" /> ''Gyo'' is utilized to focus aura on a part of the body, while ''Ten'' is used to prevent it from dispersing. ''Zetsu'' is used to completely stop the flow of Nen in all other parts of the body, increasing the output in the desired area. With ''Ren'', the amount of aura is increased even further.<ref name="chap124">Hunter × Hunter - Volume 124, Chapter 13</ref> This makes that one body part extremely powerful, but at the cost of leaving the rest of the user's body completely unprotected. Due to the risk it carries, ''Ko'' is regarded as a purely offensive technique.<ref name="chap141" /> An incomplete version of this technique can be utilized without ''Ren'', primarily to master the other steps before increasing the amount of aura to concentrate and contain.<ref name="chap124" /> Some Nen users, Enhancers in particular, employ ''Ko'' as a Nen ability by adding conditions to it.<ref name="chap211">Hunter × Hunter - Volume 20, Chapter 211</ref>

====Ken====
[[File:Gon Ken.png|thumb|left|250px|Gon using ''Ken'']]

'''''Ken''''' ({{Ruby|堅|ケン}}, ''Ken''; "Fortify") is the advanced version of the basic ''Ren'' and ''Ten'' techniques. It is a primarily defensive technique where a Nen user maintains a state of ''Ren'' for a prolonged amount of time.<ref name="chap141" /> The amount of aura surrounding the user's body during ''Ken'' is about 10 times higher than during ''Ten''.<ref name="chap142" /> ''Ken'' allows a Nen user to guard against attacks from any direction, but the large amount of aura produced makes it tiring to maintain. It is considered the best option to defend from ''Ko'', despite not being as powerful as the latter on any given part of the body, as it protects all of it evenly.<ref name="chap141" /> When not immediately at risk of being struck with ''Ko'', ''Ken'' is utilized when one wants to be cautious.<ref name="chap206">Hunter × Hunter - Volume 20, Chapter 206</ref> Some Nen users choose to expand its radius so as to sense incoming attacks they are unable to see,<ref>Hunter × Hunter - Volume 20, Chapter 210</ref> as a miniature ''En'' of sorts. Sometimes ''Ken'' is colloquially called ''Ren'' owing to the similarities between the two techniques.<ref name="chap141" />

====Ryu====
[[File:Biscuit's Ryu.png|thumb|right|250px|Biscuit using ''Ryu'']]

'''''Ryu''''' ({{Ruby|流|リュウ}}, ''Ryū''; "Flow") is the term for use of ''Gyo'' from a state of ''Ken'' to perform real-time offensive and defensive value adjustments. If ''Ko'' devolves 100% of one's aura to offense or, much more rarely, to defense, and ''Ken'' splits it evenly between the two, ''Ryu'' is redistributing one's aura according to any other percentage, for example by focusing 70% of one's aura in one fist as one is about to strike, or 80% in one's leg to block an incoming kick. It is utilized to damage a ''Ken'' user without leaving oneself as unprotected as during ''Ko'', although the power of the technique is lower. ''Ryu'' is difficult to master, as it requires not only to control one's aura flow with great precision, but also to be able to estimate the amount of aura utilized by the opponent at a glance.<ref name="chap142">Hunter × Hunter - Volume 15, Chapter 142</ref> Even if the technique is performed correctly, the movements of the aura flow risk giving away the user's next move if they are too slow.<ref name="chap206" />

==Nen and Individuality==
There are six types of aura; every individual is born having one of these six different aura types. Upon learning one's own aura type, a student of Nen can set about learning to apply the technique in a unique way that suits their personality, which can develop into a unique skill.

<center>Compatibility between Nen types
{{Switch|option1=Nen types|[[File:Nen Types Diagram.svg|thumb|center|500px|<center>Nen types distribution and relative position</center>]]|option2=Enhancer|[[File:Enhancer_Diagram.svg|thumb|center|500px|<center>Enhancer's Nen types efficiency</center>]]|option3=Transmuter|[[File:Transmuter_Diagram.svg|thumb|center|500px|<center>Transmuter's Nen types efficiency</center>]]|option4=Emitter|[[File:Emitter_Diagram.svg|thumb|center|500px|<center>Emitter's Nen types efficiency</center>]]|option5=Conjurer|[[File:Conjurer_Diagram.svg|thumb|center|500px|<center>Conjurer's Nen types efficiency</center>]]|option6=Manipulator|[[File:Manipulator_Diagram.svg|thumb|center|500px|<center>Manipulator's Nen types efficiency</center>]]|option7=Specialist|[[File:Specialist_Diagram.svg|thumb|center|500px|<center>Specialist's Nen types efficiency</center>]]}}</center>

There are numerical approximations to indicate just exactly how efficient one would be at using aura abilities that one is not born into. Starting at one's own aura type, one has the potential to be 100% efficient at using abilities based in that category alone.<ref name="chap108">Hunter × Hunter - Volume 12, Chapter 108</ref> Then looking at the category chart (see above), one has the potential to be 80% efficient at using aura types adjacent to one's primary type, 40% efficient at the opposite or farthest category, and 60% efficient in the two remaining categories. Specialization is typically unusable for non-Specialists because it is impossible to partially use; one either can or cannot use Specialist abilities. However, it is possible to turn into a Specialist later in life, with Conjurers and Manipulators having the highest chance of succeeding.<ref name="chap83">Hunter × Hunter - Volume 9, Chapter 83</ref><ref group="note" name="specialization position">Despite Izunavi stating the position of Specialization in the Nen chart is due to the fact that Conjurers and Manipulators have the highest chance of becoming Specialists later in life ([[Chapter 83]]), it has been shown multiple times that the presence of this Nen type affects all others: for example, Conjurers have 60% affinity for Manipulation instead of 80% because Specialization is located between the two in the chart ([[Chapter 83|Chapters 83]] and [[Chapter 108|108]]).</ref>

===Water Divination===
[[File:Learning by Water Divination.png|thumb|right|250px|Water Divination]]

The most popular way (and the only sure-fire way seen in the series) of determining one's aura type is through '''Water Divination''' ({{Furigana|水|みず|見|み|式|しき}}, ''Mizumishiki'').{{ref|blank|rg = note|rn = WaterDivination name|content = The Water Divination is also referred as '''Water Divination Aura Screening''' ({{Furigana|水|みず|見|み|式|しき|オーラ||選|せん|別|べつ|法|ほう}}, ''Mizumishiki Ōra Senbetsu-hō''—lit. "Water Divination Aura Sorting Method").{{ref|manga|rn=vol7p126|v=7|vp=126|d=Extra content.}}}} This divination requires one to float a leaf atop a glass of water. A student of Nen will place their hands around the glass and perform ''Ren''<ref name="chap60" /> (or focus a greater than normal amount of aura in their hands, such as through ''Gyo'').<ref name="chap376">Hunter × Hunter - Volume 36, Chapter 376</ref> The resulting effect from one's aura contacting the glass will determine a person's aura type.<ref name="chap60" />
* If the volume of the water changes, then the user is an [[Nen#Enhancement|Enhancer]].<ref name="chap60" />
* If the taste of the water changes, then the user is a [[Nen#Transmutation|Transmuter]].<ref name="chap60" />
* If impurities appear in the water, then the user is a [[Nen#Conjuration|Conjurer]].<ref name="chap60" />
* If the color of the water changes, then the user is an [[Nen#Emission|Emitter]].<ref name="chap60" />
* If the leaf moves on the water's surface, then the user is a [[Nen#Manipulation|Manipulator]].<ref name="chap60" />
* If a completely different change appears, then the user is a [[Nen#Specialization|Specialist]].<ref name="chap60" />

It is best to base a Nen ability on one's individual aura type. Though it is possible for one to develop abilities outside of his primary aura type, one is typically less proficient at using those abilities. By creating an ability that one isn't suited for, one risks stagnating their potential by overloading their capacity for using Nen<ref name="chap60" /> something [[Hisoka Morow|Hisoka]] calls "Memory Overload".<ref name="chap54" /> However, there are examples of Nen masters, such as Biscuit Krueger and Isaac Netero, who have reached a high level in multiple categories and employ them consistently in their primary Nen abilities. In fact, according to Biscuit, training in all the accessible categories is the fastest and most efficient way to improve one's skills in one's own Nen type, with the additional benefit of increasing one's flexibility and proficiency in Nen in general. A bell curve is an ideal shape, with the time spent on each category decreasing the farther away from said type is from the user's natural one.<ref name="chap144" />

===Hisoka's Personality Test===
'''Hiso-Hiso's Aura-based Personality Analysis''' (ヒソヒソのオーラ別性格分析, ''HisoHiso no Ōra Betsu Seikaku Bunseki'')<ref name="chap62" /> or '''Hisoka's Aura by Personality Diagnosis''' ({{Furigana|ヒソカのオーラ||別|べつ|性|せい|格|かく|診|しん|断|だん}}, ''Hisoka no Ōra Betsu Seikaku Shindan'')<ref name="treasure">Hunter × Hunter - Omnibus Version: Treasure [?] (pg. 492 [[File:Treasure_X_page_492_Hisoka_personality_test.png|10px]])</ref> is a Nen-type identification method invented by Hisoka by which he claims that he can judge a person's Nen-type based on their personality. According to him, all people of one aura type are generally of the same personality type. This method by his own admission, however, is no more reliable than trying to discover someone's zodiac sign or blood type from just a personality analysis.<ref name="chap62" /> According to his theory:
* '''Enhancers''' are simple and determined.<ref name="chap62" /> Most of them never lie, hide nothing, and are very straightforward in their actions or in their thinking. Their words and actions are often dominated by their feelings. They are generally very selfish and focused on their goals.<ref name="treasure" /> This is reflected in their Nen as Enhancers typically rely on simple and uncomplicated Nen abilities.
* '''Transmuters''' are whimsical, prone to deceit, and fickle.<ref name="chap62" /> Transmutation users have unique attitudes, and many are regarded as weirdos or tricksters. Often they put forth a facade while hiding the truer aspects of their personalities. Even when they don't hide their personalities they rarely reveal their true intentions.<ref name="treasure" /> Many Transmuters rely on techniques that give unique and unpredictable properties to their Nen that reflects their personalities.
* '''Emitters''' are impatient, not detail-oriented, short-tempered, and quick to react in a volatile manner.<ref name="chap63">Hunter × Hunter - Volume 7, Chapter 63</ref> They resemble the Enhancers in building their impulsivity, but the difference between them is that Emitters probably tend to calm down and forget easier.<ref name="treasure" /> Because of the nature of Emission, many Nen abilities created by Emitters are primarily long range.
* '''Conjurers''' are typically high-strung<ref name="chap63" /> or overly serious, stoic, and nervous. They are often on guard as to be cautious. They are very observant and logical, rarely falling into traps. Being able to analyze things calmly is the strength of Conjurers.<ref name="treasure" /> Many of the items that Conjurers create are often used by them in a very deliberate and practical, logical fashion.
* '''Manipulators''' are argumentative and logical. They advance at their own pace<ref name="chap63" /> and tend to want to keep their families and loved ones safe. On the other hand, when it comes to pursuing their own goals, they do not listen to what others might have to say about it.<ref name="treasure" /> While Manipulators often use techniques that allow them to control their opponents, some choose an inanimate medium to control.
* '''Specialists''' are independent and charismatic.<ref name="chap63" /><ref name="ep36(2011)">Hunter × Hunter - Episode 36 (2011)</ref> They won't say anything important on them and will refrain from being close friends, but, because of their natural charisma that draws others, they are always surrounded by many people.<ref name="treasure" /> Because Specialization is unique and can have many facets, most Specialists possess only one Nen ability.

===Telltale Signs===
[[Furykov]] was able to construct a system to identify Nen users<ref name="chap369">Hunter × Hunter - Volume 35, Chapter 369</ref> and their Nen types<ref name="chap370" /> through observation alone, which he claimed is the result of his experience. According to him, a way to differentiate between Nen users and non-users is that the outline of the former's iris, when looked at from the side, appears discontinuous.<ref name="chap369" /> One of the shortcomings of this method is that it cannot tell Nen users proper apart from individuals who have only "half-awakened".<ref name="chap372" />

A person's Nen category can be determined through some habits of theirs and the flow of their ''Ten'':
* '''Enhancers''' and '''Transmuters''', depending on their level of skill, have a soft, quiet ''Ten'' that shrouds the part of their body that activates their favorite attacks.<ref name="chap370" />
* '''Emitters''' and '''Manipulators''' generally have a broader ''Ten'', and if they attempt to shrink it, their aura will appear darker. Manipulators also tend to want to keep their dominant hand free, as it is generally the one used for their abilities.<ref name="chap370" />
* '''Conjurers''' have strong aura around the part that activates their favorite abilities and a much gentler flow everywhere else. Like Manipulators, they will also prefer to keep their dominant hand free.<ref name="chap370" />

==Aura Types==
====Enhancement====
[[File:JankenRock.png|thumb|right|250px|As an Enhancer, Gon can strengthen his fists]]

If a student increases the quantity of water in the glass during their Water Divination, then that student is an '''Enhancer''' ({{Furigana|強|きょう|化|か}}, ''Kyōka''). '''Enhancement''' ({{Furigana|強|きょう|化|か|系|けい}}, ''Kyōka-kei''; abbrev. as 強) is the ability to use aura to increase the natural abilities of an object or one's own body.<ref name="chap60" /> Therefore, Enhancers are able to greatly increase their physical attack and defense and are best suited for melee combat.<ref name="chap83" /> Proficient Enhancers who also take good care of their body can make it far more durable than tanks<ref name="chap75">Hunter × Hunter - Volume 9, Chapter 75</ref> and generate the force of a missile with one blow.<ref>Hunter × Hunter - Volume 9, Chapter 79</ref> It is rare to find male Enhancers with supportive abilities since most of them look to increase their combat prowess.<ref name="chap388" />

Enhancement is the most balanced category, allowing users to spread themselves evenly between offense and defense and become very powerful using only simple abilities. Examples of more complex Enhancement abilities include enhancing one's healing factor<ref name="chap83" /> or boosting the target's growth.<ref name="chap388" /> However, it is a common belief that Enhancers generally do not need special techniques as their natural category already has the best balance between attack and defense as its primary attribute.<ref name="chap123" /> This might play into why most Enhancement Nen abilities in the series appear to be mere applications of basic and/or advanced Nen techniques at first glance due to the lack of requirement to manage between pros and cons on an overall scale during their development. Affinity for this category, in fact, plays a crucial role in combat at all times, even when a Nen ability is not being used.<ref name="chap83" />

Notable Enhancers include:

<div style="column-count:3;-moz-column-count:3;-webkit-column-count:3">
* [[Gon Freecss]]
* {{mnls||Isaac Netero|Isaac Netero}}
* {{dtb||Maha Zoldyck|Maha Zoldyck}}
* [[Wing]]
* [[Gido]]
* {{dtb||Nobunaga Hazama|Nobunaga Hazama}}
* [[Uvogin]]
* {{dtb||Phinks Magcub|Phinks Magcub}}
* [[Palm Siberia]]
* [[Rammot]]
* {{mnls||Menthuthuyoupi|Menthuthuyoupi}}
* [[Bill]]
</div>

====Transmutation====
[[File:Killua transmuting electricity.png|thumb|right|250px|Killua can transmute his aura into electricity]]

If a student changes the taste of the water in the glass during their Water Divination, then that student is a '''Transmuter''' ({{Furigana|変|へん|化|か}}, ''Henka''). An affinity for '''Transmutation''' ({{Furigana|変|へん|化|か|系|けい}}, ''Henka-kei''; abbrev. as 変) means a person can change the properties of their aura to mimic something else, or only specific attributes.<ref name="chap60" /> Altering the shape of one's aura falls in this Nen category too.<ref name="chap146">Hunter × Hunter - Volume 15, Chapter 146</ref> Similar to Emission, constructs created via Transmutation are pure aura, therefore they are invisible to individuals incapable of using Nen. Transmutation is often mistaken for Conjuration due to their similarities. The difference is that Transmutation allows the user to mimic the properties of a substance with their aura, whereas Conjuration changes aura into the actual substance.

Transmuters are not limited to mimicking the properties of solid matter. For example, [[Killua Zoldyck]] uses his aura to mimic the properties of electricity.<ref name="chap125" /> Transmuters can also give their aura certain properties instead of replicating the characteristics of a substance in their entirety: [[Hisoka Morow|Hisoka]]'s '''Bungee Gum''' mimics and combines the properties of rubber and gum, and it is several times more flexible, sticky and durable than the real thing.<ref>Hunter × Hunter - Volume 31, Chapter 327</ref>

Notable Transmuters include:

<div style="column-count:3;-moz-column-count:3;-webkit-column-count:3">
* [[Hisoka Morow]]
* [[Killua Zoldyck]]
* {{dtb||Silva Zoldyck|Silva Zoldyck}}
* {{dtb||Zeno Zoldyck|Zeno Zoldyck}}
* {{dtb||Sadaso|Sadaso}}
* [[Machi Komacine]]
* {{dtb||Feitan Portor|Feitan Portor}}
* [[Biscuit Krueger]]
</div>

====Emission====
[[File:Nen Emitted Ball.gif|thumb|right|250px|Razor emits a ball of Nen]]

If a student changes the color of the water in the glass during their Water Divination, then that student is an '''Emitter''' ({{Furigana|放|ほう|出|しゅつ}}, ''Hōshutsu''). An affinity for '''Emission''' ({{Furigana|放|ほう|出|しゅつ|系|けい}}, ''Hōshutsu-kei''; abbrev. as 放) means that a user has an easier time separating their aura from their body.<ref name="chap60" /> Aura usually decreases in intensity very quickly when it leaves the source body, but adept Emitters can separate their aura from their body for long periods of time, over long distances, and still be able to maintain it and its functions.<ref name="chap148" />

Due to its properties, Emission is typically employed in abilities with an emphasis on range and/or those that have long-lasting effects. Basic applications include shooting out projectiles or beams of aura at high speed.<ref name="chap60" /> While this method is primarily used to attack, it can also be used to propel oneself<ref>Hunter × Hunter - Volume 7, Chapter 59</ref> or to cast an effect pertaining to another Nen type remotely.<ref name="chap361" /> Advanced applications of this Nen category include teleportation<ref name="chap374">Hunter × Hunter - Volume 36, Chapter 374</ref> and enabling one's aura to phase through non-living matter.<ref name="chap386" /> Emission has also been combined with music to achieve surprising effects, such as relieving fatigue<ref name="chap121" /> and transfixing the listeners.<ref name="chap383">Hunter × Hunter - Volume 34, Chapter 383</ref>

Emitted aura appears to cap the user's output,<ref name="chap166">Hunter × Hunter - Volume 17, Chapter 166</ref><ref name="chap245">Hunter × Hunter - Volume 23, Chapter 245</ref> and the more aura is separated from the user's body, the shorter the distance it can travel from the user.<ref name="chap68">Hunter × Hunter - Volume 8, Chapter 68</ref> In some cases, users have shown the ability to recover emitted aura; thus far, this has only occurred when Manipulation was also involved.<ref name="chap245" />

Notable Emitters include:

<div style="column-count:3;-moz-column-count:3;-webkit-column-count:3">
* [[Leorio Paradinight]]
* {{dtb||Pokkle|Pokkle}}
* [[Melody]]
* [[Shachmono Tocino]]
* [[Franklin Bordeau]]
* {{mnls||Razor|Razor}}
* {{mnls||Bloster|Bloster}}
* {{mnls||Knuckle Bine|Knuckle Bine}}
* [[Lynch Fullbokko]]
</div>

====Conjuration====
[[File:Kurapika Chains.png|thumb|right|250px|Kurapika conjures a chain]]

If a student creates an object in the water in the glass during their Water Divination, then that student is a '''Conjurer''' ({{Furigana|具|ぐ|現|げん|化|か}}, ''Gugenka''). In most cases, '''Conjuration''' ({{Furigana|具|ぐ|現|げん|化|か|系|けい}}, ''Gugenka-kei''; abbrev. as 具) is intended as the ability to create a physical, independent, material object out of one's aura;<ref name="chap60" /> however, users of this category can also create laws and principles and affix them to a specific area.<ref name="chap374" /> The durability of a conjured object can generally be taken as a measure of the user's skill, although conditions can be used to strengthen it.<ref name="chap83" />

Constructs created via Conjuration have a subtle "independence" to them: under certain circumstances, they can continue existing even at a considerable distance from the Conjurer,<ref>Hunter × Hunter - Volume 12, Chapter 109</ref> or even if the Conjurer themselves are not aware that they have yet to be de-materialized.<ref name="chap55" /> Some Conjurers have also exhibited the capacity to alter the length and size of a materialized item.<ref name="chap77" /><ref>Hunter × Hunter - Volume 31, Chapter 321</ref> Once a person has mastered the materialization of a certain object, they can conjure it and dispel it in an instant, whenever they want.<ref name="chap106">Hunter × Hunter - Volume 12, Chapter 106</ref> However, even if one were to completely master this Nen type, there would still be objects they could not materialize, such as swords that can cut anything, as they go beyond "human capacity". Izunavi vaguely described this principle as the inability to conjure objects overly supernatural.<ref name="chap83" />

Conjured objects can, in fact, possess special abilities. For instance, the Phantom Troupe thief, [[Shizuku Murasaki|Shizuku]], is able to conjure a vacuum cleaner that can infinitely suck up objects, but with the condition that it cannot suck up living things and things made out of Nen.<ref>Hunter × Hunter - Volume 8, Chapter 73</ref> Similar to Manipulation, Conjuration abilities tend to be very specific, complex, and conditional. Conditions can be imbued into conjured objects to make them stronger. [[Kortopi]], for example, is able to materialize a perfect inanimate copy of any object or person that he touches. However, the copies of all objects generated will automatically disappear after 24 hours.<ref>Hunter × Hunter - Volume 11, Chapter 103</ref> By resorting to Limitations, a Conjurer can take their ability a step further and materialize objects with properties that come even closer to exceeding human capacity, although they still cannot surpass it.<ref name="chap83" />

Conjuration is the only way in which Nen can create things that non-users can see and touch, unless they are hidden from the senses with ''In''.<ref name="chap82" /> Alternatively, Conjurers can create abilities whose constructs are invisible to non-users<ref name="chap371" /> and even specific Nen users,<ref name="chap362" /> to the point that only one person may be able to perceive them.<ref name="chap360">Hunter × Hunter - Volume 34, Chapter 360</ref> However, the fewer people are able to see a conjured construct, the lower the risk and the more energy is expended in its creation, resulting in an increased aura cost.<ref name="chap371" />

Notable Conjurers include:

<div style="column-count:3;-moz-column-count:3;-webkit-column-count:3">
* {{mnls||Kite|Kite}}
* [[Kurapika]]
* [[Shizuku Murasaki]]
* [[Kortopi]]
* {{dtb||Genthru|Genthru}}
* {{mnls||Cheetu|Cheetu}}
* {{mnls||Knov|Knov}}
* {{mnls||Welfin|Welfin}}
* [[Hinrigh Biganduffno]]
</div>

====Manipulation====
[[File:Shalnark Manipulation Nen.png|thumb|right|250px|Shalnark uses manipulation abilities to control others]]

If a student moves the leaf floating on the water in the glass during their Water Divination, then that student is a '''Manipulator''' ({{Furigana|操|そう|作|さ}}, ''Sōsa''). Abilities belonging to '''Manipulation''' ({{Furigana|操|そう|作|さ|系|けい}}, ''Sōsa-kei''; abbrev. as 操) allow the user to control living or non-living things, including aura constructs. The main advantage of this category in combat is the ability to manipulate the enemy themselves.<ref name="chap60" /> Abilities of this type are especially feared since the fight can be brought to an end as soon as the conditions are met.<ref name="chap351" /> The aura of the ability user mixes with the target's, although it is not normally noticeable.<ref name="chap388" /> The degree of control is, for the most part, determined by a condition that may or may not put the Manipulator at risk or at a disadvantage (such as attaching objects on the enemy, touching the enemy in a certain way): the higher the difficulty for the condition to be achieved, the better the degree of control. However, it is impossible to control a target that is already under the effect of Manipulation Nen.<ref>Hunter × Hunter - Volume 22, Chapter 226</ref>

Manipulators are the Nen users who can pour the most aura into an object,<ref name="chap82" /> and they often rely on a medium which they have been utilizing for years.<ref name="chap106" /> In many cases they are seen capable of inflicting and maintaining the effects of their abilities from afar, seemingly without the aid of Emission-type Nen, most commonly with the aid of a specific medium.<ref name="chap102" /><ref name="chap328" /> The complexity of the orders assigned also depends on the target: sentient beings and machinery can carry out more complex tasks, as opposed to simpler, inanimate objects.<ref name="chap50" /> Manipulation of the highest class is capable of semi-forcing the Aura Nodes of a non-user to open.<ref name="chap388" />

There are multiple types of mind control:
* '''Soliciting''' ({{Furigana|要|よう|請|せい|型|がた}}, ''yōsei-gata''—lit. "request type") Manipulators leave the free will of the victim intact, but condition them into working in their favor. An example of soliciting-type ability is rewriting the target's memories. An advantage of this type of control is that it can potentially be used on several targets by consuming only a small amount of aura. [[Halkenburg Hui Guo Rou]]'s Guardian Spirit Beast is presumed to employ this type of Manipulation Nen.
* '''Coercive''' ({{Furigana|強|きょう|制|せい|型|がた}}, ''kyōsei-gata''—lit. "compulsion type") Manipulators exert total control over the victim, taking over both their mind and body.
* '''Pseudo-coercive''' ({{Furigana|半|はん|強|きょう|制|せい|型|がた}}, ''han kyōsei-gata''—lit. "half compulsion type") Manipulators either take over the body of the victim or trap them into a situation where they have no choice but follow the Manipulator's orders. [[Momoze Hui Guo Rou]]'s Guardian Spirit Beast employs this type of Manipulation Nen.<ref name="chap372" />
* The specifics of '''diffusive induction type''' ({{Furigana|誘|ゆう|導|どう|型|がた}}, ''yūdō-gata'') Manipulation have yet to be explained in detail. It was described as weakly coercive but capable of influencing a large number of people, which it was seen doing by affecting their emotions towards a certain object. [[Salé-salé Hui Guo Rou]]'s Guardian Spirit Beast is known to exercise this type of mind control.<ref name="chap374" /><ref name="chap381">Hunter × Hunter, Chapter 381</ref>

Notable Manipulators include:

<div style="column-count:3;-moz-column-count:3;-webkit-column-count:3">
* {{dtb||Illumi Zoldyck|Illumi Zoldyck}}
* {{dtb||Kalluto Zoldyck|Kalluto Zoldyck}}
* [[Zushi]]
* [[Squala]]
* [[Baise]]
* [[Shalnark]]
* {{dtb||Morel Mackernasey|Morel Mackernasey}}
* {{dtb||Shoot McMahon|Shoot McMahon}}
* {{mnls||Ikalgo|Ikalgo}}
* {{mnls||Shaiapouf|Shaiapouf}}
* [[Boki]]
* [[Zakuro Custard]]
</div>

====Specialization====
[[File:Lovely Ghost Writer 2011.png|thumb|right|250px|Neon using her fortune telling ability]]

If a student causes some other effect during their Water Divination, then that student is a '''Specialist''' or '''Special''' ({{Furigana|特|とく|質|しつ}}, ''Tokushitsu'').<ref name="chap60" /> '''Specialization''' ({{Furigana|特|とく|質|しつ|系|けい}}, ''Tokushitsu-kei''; abbrev. as 特) could be broadly defined as anything that does not belong in any of the other five categories, making it the vaguest Nen type. Accordingly, its effects are wide-ranging: some influence ''Hatsu'' itself, for example by appropriating others' Nen abilities<ref name="chap123" /> or by altering affinities,<ref name="chap83" /> while others allow the user to garner knowledge that would be unattainable through other means, such as about past<ref>Hunter × Hunter - Volume 12, Chapter 105</ref> or future events;<ref name="chap110" /> others have completely different effects.<ref>Hunter × Hunter - Volume 23, Chapter 243</ref> Consequently, Specialists are not as much at a disadvantage as users of other Nen types if their category is revealed.<ref name="chap386" /> Only Specialists can use this Nen type. It is possible to become one later in life, although it is more likely for Manipulators or Conjurers, which is why this category is placed at the bottom of the Nen chart. Since its position is dictated by a factor other than the affinity for other Nen types, it is currently unclear if it has the same acquisition rates as other categories, although it should be noted the presence of Specialization in the chart affects other Nen types regularly.<ref name="chap83" /><ref group="note" name="specialization position" />

It is currently unknown how Specialists develop their Nen abilities. In Neon's case, she obtained an ability that she had been wishing for since she was a child,<ref>Hunter × Hunter - Volume 11, Chapter 96</ref> while Tserriednich manifested his own one week after being initiated to Nen and without trying or even being aware of it.<ref name="chap384">Hunter × Hunter - Chapter 384</ref> It seems that a Specialist's manifestation of ''Hatsu'' during Water Divination reflects their character and may thus give some insight into the general direction in which they might or should develop their ability,<ref name="chap376" /> since ''Hatsu'' is profoundly affected by personality,<ref name="chap198">Hunter × Hunter - Volume 19, Chapter 198</ref> although the information received this way is vague enough that it is impossible to pin down just what kind of ability a Specialist has already developed through their results during the Water Divination test.<ref name="chap386" />

Of the many possible effects that can occur during a Specialist's Water Divination,<ref name="chap60" /> only three have been shown so far: [[Neferpitou]]'s aura caused the leaf on top of the water to dry out and crumble;<ref name="chap198" /> Tserriednich's caused the water to boil and a putrid smell to be released;<ref name="chap376" /> and Kurapika's caused the water to change colors and the leaf to spin.<ref name="chap386" />

Notable Specialists include:

<div style="column-count:3;-moz-column-count:3;-webkit-column-count:3">
* [[Kurapika]] <small>(When [[Scarlet Eyes|his eyes turn scarlet]])</small>
* [[Neon Nostrade]]
* [[Chrollo Lucilfer]]
* {{trsv||Meruem|Meruem}}
* [[Pakunoda]]
* {{mnls||Leol|Leol}}
* [[Neferpitou]]
* {{mnls||Meleoron|Meleoron}}
* [[Tserriednich Hui Guo Rou]]
</div>


==Subcategories of Nen Abilities==
Regardless of their type, some Nen abilities share common traits that allow them to be grouped in recognizable subcategories.

===Collaborative Type===
The exact nature of '''collaborative type''' ({{Furigana|共|きょう|存|ぞん|型|がた}}, ''kyōzon-gata''—lit. "coexisting type") abilities is still unknown, but a "partner" is necessary for their usage.<ref name="chap375" />

Notable users of collaborative type abilities include:
* [[Tubeppa Hui Guo Rou]]'s Guardian Spirit Beast<ref name="chap375" />

===Compound Type===
The exact nature of '''compound type''' ({{Furigana|複|ふく|合|ごう|型|がた}}, ''fukugō-gata''—lit. "composite type") abilities is unclear. They appear to grant a variety of Nen abilities, or at least to activate a number of different effects, when certain conditions are met.<ref name="chap376" />

Notable users of compound type abilities include:
* [[Zhang Lei Hui Guo Rou]]'s Guardian Spirit Beast<ref name="chap376" />

===Counteractive Type===
[[File:Chap 373 - The Cat That Lived a Million Times.png|thumb|right|200px|Camilla's retribution on her attacker]]

'''Counteractive''' ({{Ruby|迎撃型|カウンタータイプ}} ''counter type''—base ''kanji'' lit. "interception" or "ambush attack") Nen abilities activate after the user takes damage and return it to the assailant.<ref name="chap373">Hunter × Hunter - Volume 36, Chapter 373</ref> Since the ability user strikes second, they run more risks, which increases the power of the ability.<ref name="chap375" /> The greater the damage suffered, the stronger the ensuing counter. The most effective ways to neutralize a counteractive-type Nen user are to incapacitate them without injuring them or to kill them with one blow; however, some of them can even utilize death as an activation condition.<ref name="chap373" />

Notable users of counteractive abilities include:
* [[Babimyna]]<ref name="chap366" />
* [[Camilla Hui Guo Rou]]<ref name="chap373" />
[[Feitan Portor|Feitan]]'s '''Rising Sun'''<ref>Hunter × Hunter - Volume 22, Chapter 229</ref> also seems to fulfill the criteria of the counteractive type.

===Curse===
[[File:JudgmentChain.png|thumb|right|250px|'''Judgment Chain''' around a victim's heart]]

A '''curse''' ({{Furigana|呪|のろ|い|}}, ''noroi'') is an application of Nen that is detrimental to the one upon whom it has been placed. Such curses are considered dangerous due to their long-lasting effects. The death of the caster may end up strengthening the curse, instead of weakening it. Curses may disappear if certain conditions are met by the cursed, but they can also be removed through the use of Nen.<ref name="chap120">Hunter × Hunter - Volume 13, Chapter 120</ref>

Notable curse casters include:
* Kurapika<ref name="chap120" />

Abilities with similar effects to '''Judgment Chain''' are Genthru's '''Countdown'''<ref name="chap143" /> and Knuckle's '''Hakoware''',<ref name="chap211" /> and like the former they require an Exorcism to be removed without the caster's consent.

===Diffusive Levy Type===
'''Diffusive levy type''' ({{Furigana|拡|かく|散|さん|・||徴|ちょう|集|しゅう|型|がた}}, ''kakusan chōshū-gata''—lit. "scattering/collecting type") abilities gather something from multiple targets through several agents. For example, a diffusive levy type Nen beast can summon other Nen constructs to absorb aura from numerous people at once.<ref name="chap375" />

Notable diffusive levy type ability users include:
* [[Tyson Hui Guo Rou]]'s Guardian Spirit Beast<ref name="chap375" />

===Double===
[[File:True tiger bite fist 2011.png|thumb|right|250px|Kastro summons his double]]

A '''double''' or '''doppelganger'''<ref name="chap53" /><ref name="chap368" /> ({{Ruby|分身|ダブル}}/ダブル, ''daburu''; ドッペルゲンガー, ''dopperugengā'';<ref name="chap53" /> or {{Furigana|分|ぶん|身|しん}}, ''bunshin'') is a conjured copy of the user which is then controlled via Manipulation. Automatic doubles do not require the user's focus, but they cannot carry out complex orders; vice versa, doubles which are directly controlled by the user allow for greater precision, albeit at the cost of stricter conditions.<ref name="chap368" />

Notable double users include:
* [[Kastro]]<ref name="chap53" /><ref group="note">Kastro is a double user as indicated by one of the terms (in ''kanji'': 分身, ''bunshin'') used to describe his ability to make a copy of himself; the same word is used later to describe other characters with the same type of ability, the only difference being that in the original Japanese text the ''furigana'' appears different.</ref>
* [[Hanzo]]<ref name="chap368" />
* [[Tuffdy]]<ref name="chap368" />

It is unknown whether the Royal Guard [[Shaiapouf]], who has the ability to create copies of himself out of his own cells, could be considered a double user.<ref>Hunter × Hunter - Volume 27, Chapter 284</ref><ref>Hunter × Hunter - Volume 27, Chapter 286</ref>

===Exorcism===
[[File:Wooden Effigy.png|thumb|right|250px|Abengane's exorcism which uses a wooden effigy]]

Those who possess the ability to lift curses are called '''Exorcists''' ({{Furigana|除|じょ|念|ネン|師|し}}, ''Jiyonenshi''), but are rare among Nen users. The Hunter Association may count only one among its members.<ref name="chap325">Hunter × Hunter - Volume 31, Chapter 325</ref> There are fewer than 10 people in the entire world who are powerful enough to exorcise Nen curses left by the dead.<ref name="chap120">Hunter × Hunter - Volume 13, Chapter 120</ref> Exorcism often, if not always, imposes negative conditions on the Nen user who performs it.<ref name="chap147" /><ref name="chap261">Hunter × Hunter - Volume 25, Chapter 261</ref>

Notable Exorcists include:
* [[Abengane]]<ref name="chap147" />
* [[Hina]]<ref name="chap261" />
* [[Umanma]]<ref name="chap389">Hunter × Hunter, Chapter 389</ref>
* Unknown [[Hunter Association Exorcist]]<ref name="chap325" />

[[Rihan]]'s '''Predator''' shares some affinities with exorcistical abilities, although there are also notable differences<ref name="chap374" /> which leave it questionable whether it counts as one.

===Haunting Type===
'''Haunting type''' ({{Furigana|呪|じゅ|慿|ひょう|型|がた}}, ''jiyuhyou-gata'') abilities activate after the death of the user to possess a specific target and bring them harm in a variety of ways.<ref name="chap389" /> Abilities of this type are most commonly, if not exclusively, curses.

Notable users of haunting type abilities include:
* Private Guards of Prince Camilla Hui Guo Rou<ref name="chap389" />

===Loan Type===
'''Loan type''' ({{Furigana|貸|たい|与|よ|型|がた}}, ''taiyo-gata'') abilities allow the user to transfer a Nen ability to someone else so that they can use it in place of the original owner.<ref name="chap388" />

Notable users of loan type abilities include:
* Kurapika<ref name="chap388" />

===Nen Beast===
[[File:Goreinu's Alabaster Sage & Obsidian Sage.png|thumb|right|250px|Goreinu summoning his two "''Sages''"]]

A '''Nen beast''' ({{Furigana|念|ネン|獣|じゅう}}, ''Nenjū'') is an artifact made from the user's Nen and animated through Manipulation.<ref name="chap162">Hunter × Hunter - Volume 16, Chapter 162</ref> The term is often used to refer to constructs summoned through Conjuration.<ref name="chap147">Hunter × Hunter - Volume 15, Chapter 147</ref><ref name="chap360" /><ref name="chap371" /> Their abilities and degree of autonomy vary greatly depending on the Nen ability that created it and the user's skill.<ref>Hunter × Hunter - Volume 17, Chapter 164</ref> Nen beasts generally have anthropomorphic or animal appearances, but that is not always the case.<ref name="chap360" /> Some Nen beasts have the ability to multiply themselves. Broadly speaking, this serves one of three goals:
# Increase the number of allies and control them;
# Decrease the number of enemies;
# Steal something from those who are affected by the Nen beast in order to strengthen it or its creator.<ref name="chap374" />

It has yet to be confirmed if an animated construct needs to be conjured to be classified as a Nen beast. [[Morel Mackernasey]] has shown the ability to produce automated Nen constructs without the need for Conjuration,<ref name="chap244">Hunter × Hunter - Volume 23, Chapter 244</ref> although they have never been referred to as Nen beasts. It is also unknown whether doubles are considered Nen beasts or a separate subcategory of Nen ability.

Notable users of Nen beasts include:

<div style="column-count:2;-moz-column-count:2;-webkit-column-count:2">
* [[Abengane]]<ref name="chap147" />
* [[Goreinu]]<ref name="chap162" />
* [[Razor]]<ref name="chap166" /><ref group="note">The original version of [[Chapter 166]] explicitly mentions "Razor's Nen beasts" (レイザーの 念獣が), whereas the Viz translation refers to them as "conjured goons" (without the chapter suggesting Conjuration was used).</ref>
* [[Saiyu]]<ref name="chap349" />
* [[Camilla Hui Guo Rou]]<ref name="chap373" />
* [[Tserriednich Hui Guo Rou]]<ref name="chap384" />
</div>
Depending on how this Nen ability subcategory is defined, [[Shachmono Tocino]],<ref name="chap68">Hunter × Hunter - Volume 8, Chapter 68</ref> [[Neon Nostrade]],<ref>Hunter × Hunter - Volume 8, Chapter 71</ref> [[Chrollo Lucilfer]] (through a stolen ability),<ref>Hunter × Hunter - Volume 11, Chapter 97</ref> [[Biscuit Krueger]],<ref name="chap171">Hunter × Hunter - Volume 17, Chapter 171</ref> [[Kite]],<ref name="chap194">Hunter × Hunter - Volume 19, Chapter 194</ref> Morel Mackernasey,<ref name="chap202" /><ref name="chap244" /> [[Knuckle Bine]],<ref name="chap211" /> [[Neferpitou]],<ref name="chap222" /><ref name="chap306" /> [[Flutter]],<ref>Hunter × Hunter - Volume 23, Chapter 246</ref> [[Ikalgo]] (through a reanimated corpse),<ref>Hunter × Hunter - Volume 26, Chapter 273</ref> [[Kurapika]],<ref name="chap361" /> [[Musse]],<ref name="chap366" /> [[Benjamin Hui Guo Rou]] (through an inherited ability),<ref name="chap373" /> [[Rihan]], [[Yushohi]],<ref name="chap381" /> and [[Hinrigh Biganduffno]]<ref>Hunter × Hunter, Chapter 390</ref> might also make use of Nen beasts. [[Nasubi Hui Guo Rou]] and his 14 children are all hosts of parasitic Nen beasts, granted to them by an ancestor through the Seed Urn Ceremony.<ref name="chap349" />

===Parasitic Type===
''See also: [[Guardian Spirit Beast]]''

When a Nen user imposes an ability on another person which feeds off that person's aura to manifest its effects, that ability is classified as '''parasitic''' ({{Furigana|寄|き|生|せい|型|がた}}, ''kisei-gata''). Parasitic type abilities are similar to [[Nen#Curse|curses]] and are often conjured. They act without the host's awareness or control, defending him/her and, in rare cases, attacking. The person who receives the ability may not even be aware of it or be a Nen user, in which case they will be unable to see the ability. The latter case is the most favorable for parasitic Nen, as the host will be unaware of their aura being drained and will only feel tired.<ref name="chap360" /> Many abilities of this type feed off the emotions of the recipient as well as of those of the people around them, resulting in complex, unpredictable Nen constructs.<ref name="chap362" />

Notable users of parasitic Nen include:
* The First King of Kakin, who created the [[Guardian Spirit Beast#The Seed Urn|Seed Urn]]<ref name="chap349" />
* [[Momoze Hui Guo Rou]]'s Guardian Spirit Beast<ref name="chap361" />

Notable hosts of parasitic Nen include:
* [[Nasubi Hui Guo Rou]]<ref name="chap349" />
* The 14 Princes of Kakin<ref name="chap349" />

===Supportive Type===
'''Supportive''' ({{Furigana|補|ほ|助|じょ|型|がた}}, ''hojo-gata'') abilities appear to be those abilities that are not aimed at increasing the user's combat strength, which makes this class considerably vast. The only confirmed ability of this type is [[Bill]]'s '''Erigeron''', which uses Enhancement to induce the growth of his target.<ref name="chap388" />

===Symbiotic Type===
[[File:Golem Symbiotic Type Arm.png|thumb|right|200px|Golem's symbiotic type arm]]

Some abilities are collaborative in that they require multiple Nen users to donate aura<ref name="chap361" /> or perform each a different task to be effective. The power of the resulting ability is greater than what the Nen users involved could achieve individually.<ref name="chap347">Hunter × Hunter - Volume 33, Chapter 347</ref> Such abilities are classified as '''symbiotic''',<ref name="chap375" />'''symbiotic type''' or '''joint type''' ({{Ruby|相互協力型|ジョイントタイプ}};<ref name="chap347" /> base ''kanji'' lit. "mutually cooperative type"; or {{Furigana|相|そう|互|ご|協|きょう|力|りょく|型|がた}},<ref name="chap375" /> ''sōgo kyōryoku-gata''). An example of symbiotic ability is conjuring a weapon which is then loaded and fired by another Nen user, such as an Emitter.<ref name="chap347" /> A subcategory of symbiotic type abilities acts on whole groups and is therefore classed as '''fellowship''' or '''party form''' ({{Ruby|集団行動形式|パーティーフォーム}}; base ''kanji'' lit. "group action form").<ref name="chap375" />

Notable joint type Nen users include:
* [[Golem]]<ref name="chap347" />
* [[Kurton]]<ref name="chap361" />
* [[Halkenburg Hui Guo Rou]]'s Guardian Spirit Beast (party form)<ref name="chap375" />
* [[Fugetsu Hui Guo Rou]]'s Guardian Spirit Beast<ref name="chap383" />
* [[Kacho Hui Guo Rou]]'s Guardian Spirit Beast<ref name="chap383" />

[[Tsubone]]<ref>Hunter × Hunter - Volume 31, Chapter 329</ref> and [[Morena Prudo]]<ref>Hunter × Hunter - Volume 36, Chapter 378</ref> may utilize this type of sub-ability as well, the latter in party form. '''Countdown''' may also have symbiotic elements in its remote detonation, since, despite it being Genthru's ability, two more people are necessary to activate this aspect of it.<ref name="chap144" />

==Nen and Risk==
[[File:113 - Shoot smiling at Youpi.png|thumb|left|250px|Shoot covers his eye to increase risk]]

Together with emotion, '''risk''' (リスク, ''risuku'') is one of the factors which has a remarkable effect on Nen. Self-imposed stipulations that are harmful or potentially so to the creator, such as willingly limiting the use of their senses, can increase the power of their Nen, and of their Nen abilities in particular.<ref name="chap254">Hunter × Hunter - Volume 24, Chapter 254</ref> This is because Nen is an expression of willpower, and willingly taking extra risks confirms the Nen user’s resolve.

{{Clrl}}
It is interesting to note that while it is enough to feel certain emotions for them to affect one’s aura, determination becomes a factor only when manifested through the addition of conditions: for example, while Kurapika always had the resolve to fight the Phantom Troupe even at the cost of his life, it was only when he decreed that he would die if he used '''Chain Jail''' on someone other than a Spider that he was able to create the ability.<ref name="chap83" /> The reverse is also true, with restrictions granting greater power to a Nen user even on occasions where they run no risks, such as when Gon charged his '''Rock''' to acquire "[[King White Stag Beetle (G.I card)|King White Stag Beetle]]"<ref name="chap150">Hunter × Hunter - Volume 15, Chapter 150</ref> and during the dodgeball match against Razor.<ref>Hunter × Hunter - Volume 17, Chapter 165</ref>

===Vows and Limitations===
[[File:Self imposed restriction.png|thumb|right|250px|Vows and Limitations]]

Being a product of the mind, Nen responds to the goals, strengths, and desires of individual users. As a result, a student of Nen can increase the overall power of an individual skill by stating a self-imposed restriction that forces even more conditions on it. For example, if one consciously decides something along the lines of "''I will only use this skill on Thursdays''" or "''I will only use this skill against short people''" and manages to abide by that rule, that particular skill will become stronger. These restrictions are called "'''Limitations'''" ({{Furigana|制|せい|約|やく}}, ''Seiyaku'', or {{Ruby|制約|ルール}}, lit. "Rule"), and the act of swearing to respect them "'''Vow'''" ({{Furigana|誓|せい|約|やく}}, ''Seiyaku'') or "'''Contract'''". The stricter the Limitation, the stronger the user's resolve, and thus the more their ability is strengthened. However, Limitations are also considered liabilities, since the power they grant is not consistent.<ref name="chap83" />

Unlike normal conditions, which establish the general parameters of an ability, and activation requirements, which determine the circumstances in which said ability can be used, a Limitation can be broken; however, doing so not only entails the loss of the ability it was used on, but it also carries the risk of obliterating one's capacity to use Nen altogether.<ref name="chap83" /> Limitations that contain some sort of punishment (e.g. "''I will die if I break this rule''") will strengthen the ability even further.<ref name="chap83" /> An example is provided by [[Kurapika]], who swore on his own life not to use an ability on anyone but the [[Phantom Troupe]].<ref name="chap77">Hunter × Hunter - Volume 9, Chapter 77</ref> According to [[Izunavi]], without that added risk, the ability would not have worked.<ref name="chap83" />

===Conditions===
Aside from Vows and Limitations, the creator of a Nen ability can include '''conditions''' ({{Furigana|条|じょう|件|けん}}, ''jōken'') in it to increase its power or to make the ability feasible in the first place, whether because the user lacks the degree of skill otherwise required,<ref name="chap108" /> or because the effects of the ability exceed what can be achieved with Nen without a trade-off.<ref name="chap98" /> Much like Limitations, conditions are based on the principle of equivalent exchange, although they are seemingly weaker<ref>Hunter × Hunter - Volume 10, Chapter 84</ref> and may occasionally be rendered redundant by high proficiency in Nen.<ref name="chap108" /> Unlike Limitations, which can be broken, albeit at a severe cost, it does not appear to be possible to violate the conditions of an ability.<ref name="chap134" /> The three categories at the bottom of the Nen chart—Conjuration, Specialization, and Manipulation—are the ones that appear to rely on conditions the most.

The unconscious of the ability creator plays a fundamental role in determining the exact boundaries of a condition where those boundaries are not rendered explicit. '''Order Stamp''' works only on puppets, which are defined as “non-living objects with a discernible head”; vice versa, this means that if the puppet’s head is removed, it ceases to be counted as such and the ability terminates. Additionally, since the creator did not view human corpses as mere objects, despite them otherwise fitting the definition of puppet, Chrollo, who inherited the ability and had no such compunction, was still unable to manipulate corpses via '''Order Stamp''', which however could be used on replicas of corpses.<ref name="chap352" />

====Activation Requirements====
Many Nen abilities can be activated only after fulfilling certain conditions, which are known as '''activation requirements''' (発動条件, ''hatsudō jōken''):<ref name="chap379">Hunter × Hunter - Volume 36, Chapter 379</ref> Shalnark and Illumi are Manipulators who need to stick a specific object into the target to be able to control them,<ref name="chap102">Hunter × Hunter - Volume 11, Chapter 102</ref><ref name="chap328">Hunter × Hunter - Volume 31, Chapter 328</ref> whereas Genthru must touch his target while uttering a keyword and then give a proper explanation of all his Nen abilities to activate '''Countdown'''.<ref name="chap143">Hunter × Hunter - Volume 15, Chapter 143</ref> Certain abilities have interchangeable requirements, such as Leol needing to either know the name of the ability he wants to borrow or see it in action,<ref name="chap248">Hunter × Hunter - Volume 24, Chapter 248</ref> or a photograph being a satisfying replacement for the target of '''Lovely Ghostwriter''' if they are not present in person,<ref name="chap110">Hunter × Hunter - Volume 12, Chapter 110</ref> which increases the user’s chances of success. Activation requirements may also be continuous, meaning that as soon as they are contravened, the connected ability is cancelled (e.g. a puppet controlled with '''Order Stamp''' losing its head and thus no longer qualifying as a puppet).<ref name="chap352" />

Some activation requirements are common to many, if not all, Nen abilities with similar effects. It is well-known that not any medium can be chosen for Manipulation abilities, but that it must be an object which the user has been using for years<ref name="chap106" /> and to which they're deeply attached.<ref name="chap50" /> Likewise, it was estimated that all Nen users who steal Nen abilities and use them for themselves must meet four or five conditions before they can do so,<ref name="chap98" /> and in general their death causes the restitution of the stolen abilities.<ref name="chap352" /> An activation requirement can be so common that it is given a name, as is the case for '''Marking''' (マーキング), which establishes that a teleportation ability can allow the user only to "jump" ({{Ruby|移動|ジャンプ}} ''transfer'') to a location they had already visited in the past.<ref name="chap379" />

====Other Conditions====
Additional conditions that are unrelated to paying the activation cost of an ability and which limit the range of its potential usages after also exist. The inherent impossibility of breaking such restrictions allows the user to turn them to their advantage: Shizuku’s '''Blinky''' is unable to suck in living objects and items created from aura, the latter of which she can exploit to detect traps laid with Nen.<ref name="chap134" />

[[File:Feitan and Franklin Auction.png|thumb|left|250px|Franklin's severed fingers]]

Some conditions are deeply tied to the user’s emotion, to the point of being implemented simply because they "feel right".<ref name="chap146" /><ref name="chap150" /> Notable examples are Franklin’s severing his own fingers to use his '''Double Machine Gun'''<ref>Hunter × Hunter - Volume 9, Chapter 76</ref> and Gon’s chant while preparing a '''Jajanken''' attack, increasing risk through a long wind-up and leaving himself unprotected for a few seconds.<ref name="chap211" />

There are also conditions that do not regulate the manner in which a Nen ability is to be used, but which impacts the user negatively in return for use of the ability. Unlike the penalties that some Limitations contain, they are not activated when a certain rule is broken and do not impair the user’s Nen abilities, but function as a toll of sorts: an instance is Kurapika’s '''Emperor Time''', which shortens his lifespan by one hour for each second it is active.<ref>Hunter × Hunter - Volume 35, Chapter 364</ref>

====Loopholes====
[[File:Chrollo Order Stamp.png|thumb|right|200px|Chrollo using two stolen abilities at the same time]]

In general, it does not appear to be possible to break a condition; however, there are Nen users who create additional abilities to bypass certain restrictions of others, so as to be capable of circumventing them under very specific circumstances. The most notable instance is Chrollo's creation of his '''Double Face''' ability, which enables him to modify the requirements of '''Skill Hunter''' that would otherwise prevent him from using more than one stolen ability at a time and from keeping both of his hands free in exchange for the addition of extra Limitations.<ref name="chap351" /> Likewise, Gon can charge two '''Jajanken''' attacks simultaneously thanks to a technique called '''Round 2''',<ref name="chap209" /><ref name="chap211" /> although it is not clear whether it is a loophole in '''Jajanken''' or a Nen ability proper.

==Quantification of Aura==
===Enhancement and Limitations===
Reinforcement Nen plays a crucial part in combat, and as such, one's affinity for said Nen category is a factor of paramount importance. For example, while a skilled Conjurer may be unable to fully block 9mm bullets with ''Gyo'',<ref name="chap370" /> some master Enhancers can utilize ''Ten'' or ''Ren'' to resist sniper bullets without a single scratch, as well as to come out of the head-on explosion caused by an anti-tank bazooka with only minor burns.<ref name="chap75" /> When two Nen users clash, it is possible to make predictions about the outcome through a simple equation. Physical strength is represented by the acronyms '''AP''' (Attack Points; アタックポイント) and '''DP''' (Defense Points; ディフェンスポイント{{Infer|Due to the context and meaning of the other acronyms.}}), depending on the action of the Nen user, while the proficiency in Enhancement is expressed in '''SP''' (Spirit Points; センスポイント, lit. "Sense Point"). The sum of these two factors indicates the value of one's offensive or defensive capabilities.

If an Enhancer and a Conjurer who possess equal physical strength and who have maximized Nen reinforcement were to clash, and the Enhancer was the one attacking, his attack power would be expressed as:

<center>AP + SP → {{Ruby|100|AP}} + {{Ruby|100|SP}} = 200</center>

For the Conjurer, who has the same physical strength but whose proficiency in Enhancement would not exceed 60% even if maximized, his defense power would be:

<center>DP + SP → {{Ruby|100|DP}} + {{Ruby|60|SP}} = 160</center>

The equation representing the action is:

<center>(DP + SP) - (AP + SP) → ({{Ruby|100|DP}} + {{Ruby|60|SP}}) - ({{Ruby|100|AP}} + {{Ruby|100|SP}}) = -40</center>

Thus the Conjurer would suffer 40% of the damage even if he managed to block the attack correctly. This method is a simplification, since physical strength and aura output differ from person to person, and the location, environment and moment of the attack are fundamental variables in a real fight. Nen itself is much more complicated since its power varies depending on the user's mental state. Because of this, it is possible to use a Limitation to strengthen one's will and thus one's aura, exceeding the normal limit. If in the same instance as before the Conjurer used a Limitation worth 2 '''MP''' (Mystery Points; ミステリーポイント), his defense would become:

<center>DP + SP × MP → {{Ruby|100|DP}} + ({{Ruby|60|SP}} × {{Ruby|2|MP}}) = 220</center>

As a consequence, the equation would be:

<center>(DP + SP × MP) - (AP + SP) → [{{Ruby|100|DP}} + ({{Ruby|60|SP}} × {{Ruby|2|MP}})] - ({{Ruby|100|AP}} + {{Ruby|100|SP}}) = 20</center>

In this case, the Conjurer would be able to block the Enhancer's attack without suffering any damage. However, due to the inherent risks of a Limitation and exceeding one's 100% limit, not all Nen users decide to resort to this method.<ref name="chap83" />

===Level, Force, and Accuracy===
A Nen user's "'''Level'''" in a Nen type determines the abilities that Nen user can learn. It could be tentatively defined as one's degree of proficiency in a Nen type which translates in the creation of a specific ability. A Level 10 Conjurer can only master Conjuration abilities that require an amount of skill equal to or lower than Level 10. The Level of one's natural category determines the ceiling for all others, which can be calculated by applying the rule of affinity: a Level 10 Conjurer can master Transmutation abilities only up to Level 8, Enhancement and Manipulation abilities up to Level 6, and Emission abilities up to Level 4, unless he raises his Level in Conjuration by training in it<ref name="chap108" /> (or by training other types, which would cause his skills, and thus his Level, in Conjuration to increase as well).<ref name="chap144" />

[[File:Nen_Level,_Force,_and_Accuracy_(1).png|center|250px]]

However, while said Conjurer could potentially create the same ability as a Level 4 Emitter, his effective output would pale in comparison with the Emitter's. The reason is that the law of acquisition rates applies a second time, making it so the "'''Accuracy'''" and "'''Force'''" (which have also been translated collectively as "'''Effectiveness'''" or "'''Power'''") of a Nen ability are proportional to the predisposition of the user for the category the Nen ability requires. As a consequence, if the Level 10 Conjurer and Level 4 Emitter from the example used the same Level 4 Emission ability, the Force and Accuracy of the Conjurer would amount to a measly 40% of the Emitter's, who has 100% affinity, and thus 100% Force and Accuracy, for that type.<ref name="chap108" />

[[File:Nen_Level,_Force,_and_Accuracy_(2).png|center|300px]]

===Aura Power===
[[Knuckle Bine]] devised a way to convert aura in a numeric value, and use it in a system similar to the process of finding the Capacity factor of a power plant, in this case, the power plant being the Nen user and the energy being the aura. The arbitrary unit of his system corresponds to the approximate amount of aura spent every second by a Nen user in battle mode (1 unit per second), and it is called "aura". However, once the fight starts, the aura consumption increases up to 6 or even 10 aura per second, due to the usage of techniques like ''Ryu'' and ''Ken'' and of Nen abilities. The less skilled the Nen user and the more powerful the technique, the more aura is consumed this way. Inexperienced users can consume as many as 10 aura per seconds with ''Ken'', with the annexed increase when they utilize advanced techniques. After assessing how much aura his opponents spend in combat every second and for how long they can keep using it, Knuckle is able to estimate the total amount of aura they can access. He uses three parameters:

[[File:MOP.jpeg|thumb|right|200px|Knuckle explains his concept of MAP]]

* '''Maximum Aura Power''' or '''M.A.P.''' (最大オーラ量 or ＭＯＰ):<ref group="note" name="aura acronym">In Japanese, the acronyms MAP, PAP, and AAP were written as MOP, POP, and AOP due to the ''katakana'' transcription of "Aura", which is "オーラ", or, in ''rōmaji'', "''Ōra''". To preserve the original acronym, Viz excluded "Aura" from them in the translation, with the "O" standing for "Output". Furthermore, the "P" in all three acronyms stands for "Power", but the ''kanji'' "量" actually means "volume".</ref> the amount of aura stored inside the body of a Nen user. It varies for each individual and can be increased through training.
* '''Potential Aura Power''' or '''P.A.P.''' (潜在オーラ量 or ＰＯＰ):<ref group="note" name="aura acronym" /> the amount of aura that a Nen user can expend before passing out. It appears to correspond to how much of their M.A.P. a Nen user can access at a specific point in time.

[[File:AOP & Pop.jpg|thumb|right|200px|AAP and PAP]]

* '''Actual Aura Power''' or '''A.A.P.''' (顕在オーラ量 or ＡＯＰ):<ref group="note" name="aura acronym" /> the quantity of aura that is used effectively at any moment; in other words, aura output. This is what determines the efficiency of the Nen user in a combat situation, as a high P.A.P. with a low A.A.P. is meaningless. A.A.P. can be increased through training. It is also influenced by how well an individual can use Nen: lack of practice or low affinity for a certain Nen category can cause the power of an attack to be lower than the aura units expended. For example, when Gon used his '''Round 2''' technique against Knuckle, he consumed 4000 aura to charge two abilities, '''Jajanken: Rock''' and '''Jajanken: Paper'''; however, the actual force of the Emission attack was equivalent only to 500 aura, 25% of the power of '''Jajanken: Rock''' and 12.5% of the aura consumed overall.<ref name="chap211" />

==Training Exercises==
Orthodox Nen training<ref name="chap366" /> begins with meditation exercises,<ref name="chap363" /> which are aimed at allowing the student to gradually become aware of their aura flow even before their Aura Nodes are opened and to start to control it.<ref name="chap48" /> In Shingen-ryu ''kung fu'', the ''Ten'' step in the Nen of the Flame is also utilized as a way for the student to polish their mind and thus the flow of their ''Ten''.<ref name="chap56" />

The first meditation exercise<ref name="chap363" /> has the aim of ascertaining the student's natural potential. The student is required to put their index fingers slightly apart, and have the tips close in on each other until they have the sensation of pushing against something. The farther apart the fingertips are when the student begins to feel the presence of aura, the greater their predisposition.<ref name="chap370" /> What follows are the basics of aura manipulation, even if the student is still incapable of seeing aura. In the first and only known exercise of this phase, the student is to place their hands in front of their chest and imagine forming a ball between them. This exercise is meant to develop the student's ability to feel their own aura. In general, it is performed for 10 days, with 3 sets of 10 minutes every day; particularly talented individuals can begin to sense their aura in 5 to 7 days, although in extremely rare cases some may succeed on the first try.<ref name="chap366" />

Students generally learn to open the Aura Nodes in their eyes, thus obtaining the ability to see aura, in about one year,<ref name="chap362" /> although gifted individuals can grasp the basics of Nen in six months.<ref name="chap368" /> Once all of the student's nodes are opened, which normally occurs after one year of three hours of basic exercises every day,<ref name="chap388" /> they are introduced to the first principle, ''Ten'',<ref name="chap56" /> learning to contain the leaking aura little by little through breathing exercises.<ref name="chap388" /> Next is ''Ren'', which in turn leads to ''Gyo'' and other techniques.<ref name="chap56" /> ''Hatsu'' is first trained through the Water Divination exercise, by having the student attempt to produce a more pronounced change.<ref name="chap60" />

Mastering ''Ten'' in six months is indicative of uncommon talent.<ref name="chap48" /> Regardless of their level, it is advised Nen practitioners train their ''Ten'' and ''Ren'' daily,<ref name="chap123" /> since they are the foundations of all advanced techniques.<ref name="chap56" />

===Biscuit's Training===
Biscuit has devised exercises to train her students in every aspect of Nen after they master the basic techniques enough to pass the secret Hunter Exam. She models her coaching method on her students to best suit their needs, often giving them very precise instructions but also letting them reach the answer on their own from time to time. Unlike her former pupil Wing, she has her students train their guard and physical, combat and analytical abilities together with Nen. By her own admission, her regimen is much harder than his.<ref>Hunter × Hunter - Volume 14, Chapter 138</ref>

====Gyo Training====
The first exercise she has her students perform requires them to rapidly activate ''Gyo'' on their eyes and tell her what number she is forming with her ''In''-concealed aura whenever she raises her index finger. Should she have more than one student, she makes them compete amongst each other, and the slower one to respond is penalized with physical exercises.<ref name="chap136">Hunter × Hunter - Volume 14, Chapter 136</ref> Should all her students be too slow, all of them will be punished.<ref name="chap140" /> There is no set time for this exercise, and in fact, it is used to teach students to remain constantly vigilant and activate ''Gyo'' at the slightest hint of danger until it becomes second nature to them.<ref name="chap136" />

====Shu Training====
On [[Greed Island]], Biscuit had Gon and Killua dig through rock formations using regular shovels, confiding that they'd be able to figure out the existence of the technique and how to utilize it all on their own.<ref name="chap140" />

====Ken Training====
After explaining how to perform ''Ken'', Biscuit proceeds to demonstrate ''Ko'' and demands that her students maintain ''Ken'' for at least thirty minutes, during which she holds ''Ko'' as if about to strike.<ref name="chap141">Hunter × Hunter - Volume 15, Chapter 141</ref> Once they manage to hold the technique for that long, she hits them with a slow-moving ''Ko'' punch to test their resistance.<ref name="chap142" />

====Ryu Training====
When a student manages to hold ''Ken'' for at least 30 minutes, they are ready to learn ''Ryu''. Biscuit instructs them on which proportions of their aura to focus on which body part for 30 minutes, three times a day. At the same time, her students are introduced to the ''kumite'' section of her program, in which they spar using ''Ryu'', so as to learn how to adjust their aura flow while attacking and defending.<ref name="chap142" />

====Ko Training====
Biscuit's exercises or ''Ko'' training were not shown, but it appears the technique is taught at some point after the ''Ken'' exercises<ref name="chap141" /> and before the Nen type ones, as the first of the latter requires the use of ''Ko''.<ref name="chap145" />

====Nen Type Training====
''See also: [[Biscuit Krueger#Nen Type Training|Biscuit's Nen Type Training]]''

These exercises are structured in levels, and the student can generally progress to the next after achieving a certain degree of mastery over a lower one. Her students train in all accessible Nen types, as, on top of granting them more flexibility, this allows them to progress in their own category more quickly.<ref name="chap144" /> Her fundamental rule is that only one Nen category can be trained a day.<ref name="chap145" /> Students normally focus on their natural category every other day, while in the other Nen types are rotated and more are added as the student progresses.<ref name="chap146" /> When coaching Gon and Killua, Biscuit introduced them to Enhancement first,<ref name="chap145" /> and seemingly saved Manipulation for last.<ref name="chap146" />

<gallery type="slideshow" widths="250" hideaddbutton="true">
Biscuit Crake the rock.jpg|Biscuit's smashing a rock
Nen Number.jpg|Nen number
Hunter X Hunter 65.mkv snapshot 20.35 -2013.03.29 18.01.59-.jpg|Aura throwing
Aura Levitation 2011.png|Aura levitation
</gallery>

'''Enhancement Training'''
* ''Level 1 - Rock Breaking''
The student enhances a stone's durability using ''Shu'' and ''Ko'' to repeatedly smash other rocks without breaking the one they are holding. The exercise terminates either when a student manages to break 1000 rocks in a day, in which case they are ready for the next level, or when the stone they are holding shatters. On top of the aura consumption, the repetitive movement puts stress on the student's focus, causing their aura control to become less and less precise. Only one try a day is allowed.<ref name="chap145" />

'''Transmutation Training'''
* ''Level 1 - Shape-shifting''
The student must form the numbers 0 through 9 on top of their finger by manipulating the shape of their aura, much like Biscuit does to train their ''Gyo'', while also running. The student can proceed to the next level once they manage to form the 10 numbers in one minute, with the end goal being 5 seconds.<ref name="chap146" />

'''Emission Training'''
* ''Level 1 - Name Unknown''
This exercise is comprised of two parts. In the first, the student must form a small bubble out of their aura from the tip of their finger and maintain it in place for one minute. Once they manage to do so, they have to attempt to throw it over a certain distance without the bubble dissipating. The time the aura bubble can be maintained afloat reflects the strength of one's ''Ten''. An effort is also required to maintain the shape of the bubble.<ref name="chap148" />

* ''Level 5 - Floating Hand''<ref name="chap171" />
The student positions into a one arm handstand, then they project their aura outwards explosively from the hand that is touching the ground so as to propel themselves into the air. The student can proceed to the next level once they manage to launch themselves a few dozen centimeters; otherwise, they keep practicing for as long as they can maintain the handstand. A student who has mastered this level is able to knock an opponent back a dozen feet with an Emission attack.<ref name="chap171" />

====Ren Training====
Very similar to the basics of ''Ken'' training, this step of Biscuit's regimen is intended to increase the student's aura pool, in particular, to allow them to maintain ''Ken'' for longer in combat. In order to accelerate progress, she can speed up the student's recovery with her Nen ability.<ref name="chap201" /> Once the student manages to maintain ''Ren'' for three hours, they will still have to hold it for that amount of time once a day. Biscuit also had Gon and Killua fight Knuckle right after the end of the exercise.<ref name="chap202" />

===Kurapika's Training===
According to Kurapika, the way a person feels most comfortable clasping their hands together can hold information about the best way to introduce them to the basics of Nen. There are at three groups:
* Those who touch their palms together and interlock their fingers as if in prayer are called "'''prayers'''" ({{Furigana|祈り|プレイ|型|がた}}, ''purei-gata''—lit. "pray-type"). The first exercise for them is to imagine scooping up water with their eyes closed.
* Those who grasp their hands like during a handshake are named "'''shakers'''" ({{Furigana|握手|シェイク|型|がた}}, ''sheiku-gata''—lit. "shake-type"). The first exercise requires them to hold hands in a circle and to imagine their aura flowing clockwise.
* Those who grasp their wrist are called "'''catchers'''" ({{Furigana|片手主導|キャッチ|型|がた}}, ''kyatchi-gata''—lit. "catch-type"). The first exercise requires them to spin their hands in a circle as if to make cotton candy.<ref name="chap371" />

With this method it is supposedly possible to learn to generate enough aura to perform the Water Divination test after only one week of training;<ref name="chap386" /> in reality, however, none of Kurapika's students performed their first Water Divination with their own aura, as they had their Aura Nodes semi-forced open by his Nen ability. Kurapika implied to [[Hashito]] that his training is what prevented his students from depleting their aura reserves after being "initiated", which would mean that its real purpose was to introduce his students to the basics of aura manipulation.<ref name="chap388" />

===Izunavi's Conjuration Training===
The first step for a Conjurer to develop a Nen ability is to decide what object they want to materialize. Then, they must undergo intense imagery training by being in contact with said object every waking moment, studying them with all five senses and drawing pictures of them. When the student begins to dream about the intended object every time, the teacher takes it away from them. The dreams are subsequently replaced by hallucinations, which get more and more real to the point they also involve the senses of touch and hearing until the Conjurer unwittingly materializes one.<ref name="chap123" />

==Trivia==
* In the manga, six characters have used Nen before it was explained to Gon and Killua: Gon,<ref name="chap50" /> Illumi<ref>Hunter × Hunter - Volume 3, Chapter 26</ref><ref>Hunter × Hunter - Volume 4, Chapter 35</ref><ref>Hunter × Hunter - Volume 5, Chapter 36</ref> ([[Hunter Exam arc]]), Zebro<ref>Hunter × Hunter - Volume 5, Chapter 39</ref> ([[Zoldyck Family arc]]), Zushi, Wing,<ref>Hunter × Hunter - Volume 6, Chapter 45</ref><ref name="chap46" /> and Hisoka<ref name="chap47" /> ([[Heavens Arena arc]]).
* [[Kurapika]] is the only character who falls under two different Nen categories.
* Manipulation is the only category of Nen that none of the protagonists fall under.
* Aura can be filmed,<ref name="chap56" /><ref name="chap57" /> but it will still remain invisible to those who cannot use Nen.<ref>Hunter × Hunter - Volume 21, Chapter 223</ref>
* Curiously, despite sound having very different physical properties from light and thus hearing differing from sight, non-users are unable to hear sounds made by Nen constructs.<ref name="chap361" />
* According to [[Hisoka Morow|Hisoka]], Enhancers and Transmuters have opposite personalities, and they might be attracted to each other because of it. There are several instances of this happening in the series:
** [[Gon Freecss|Gon]] and [[Killua Zoldyck|Killua]]: They are best friends.
** Gon and Hisoka: Hisoka is attracted to and fond of Gon, and has aided (or refrained from harming and/or killing) him on numerous occasions, although the interest is not reciprocated.
** [[Phinks Magcub|Phinks]] and [[Feitan Portor|Feitan]].
** [[Isaac Netero|Netero]] and [[Zeno Zoldyck|Zeno]]: According to the latter, they are like "''Yang''" and "''Yin''" respectively.
** It is interesting to note that there is some enmity between Transmuters and Enhancers in the series. For example, the Enhancers Uvogin, Phinks, and Nobunaga didn't get along well with Hisoka, a Transmuter.
* While using ''Ken'', Gon's aura output during his final fight against Knuckle was about 1800 aura units, and a punch thrown in that state 150 aura units.<ref name="chap211" /> This might mean that on average, a ''Ken'' punch contains 1/12th of the user's total aura output.
** A similar calculation may be used to determine a relation between aura output and aura reserves. If Gon's M.A.P. (21,500 aura units) is divided by his output (1800 aura units), the result is approximately 12. However, the output is a factor that can vary with training,<ref name="chap211" /> and Gon's has always been considered exceptional.<ref>Hunter × Hunter - Volume 17, Chapter 167</ref> Furthermore, it used to fluctuate with his emotions.<ref>Hunter × Hunter - Volume 20, Chapter 207</ref> All of this suggests that his values may not be reliable to establish a general law.
* The terms used for "Vows" and "Limitations" are homophones in Japanese (せいやく, ''Seiyaku'').

===Anime and Manga Differences===
[[File:Nen equation.jpg|thumb|right|160px|The equation according to the anime]]

* In the 2011 anime, the equation representing the power of Limitations is different from its counterpart in the manga, with Mystery Points affecting both Attack Points and Spirit Points:<ref>Hunter × Hunter - Episode 47 (2011)</ref>

<center>(AP + SP) × MP = ?</center>

{{Clrr}}
===Intertextuality and References===
* In [[wikipedia:Yu_Yu_Hakusho|''YuYu Hakusho'']], [[Yoshihiro Togashi|Togashi]]'s previous manga, [[w:c:yuyuhakusho:Minoru_Kamiya|Minoru Kamiya]] is said to use a virus made from aura or Nen ({{Ruby|念|ねん}}).<ref>YuYu Hakusho - Volume 14 (page 66), Chapter 122 (page 1)</ref>
* The Water Divination Aura Screening may have been loosely inspired by the concept of [[wikipedia:Hydromancy|hydromancy]] (a.k.a. "water-divination")—a method of divination by means of water, including the interpretation of color, ebb, and flow, or ripples produced in perturbed water.

===Miscellaneous===
* Aura is translated as "''Chi''" (氣) in the Chinese edition of Hunter × Hunter. ''Chi'' is known as "''Ki''" (気) in Japanese.

==Translations around the World==
{{Langtable
|ar = نين (''Nayn'')
|ch = 念能力 (''Niàn Nénglì'')
|ru = Нэн (''Nen'')}}

==References==
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<references />}}
{{references|note|box=yes}}

<!-- Interlanguage/Interwiki links -->
[[ar:نين]]
[[de:Nen]]
[[es:Nen]]
[[fr:Nen]]
[[ms:Nen]]
[[pl:Nen]]
[[pt:Nen]]
[[ru:Нэн]]
[[zh:念能力]]
[[Category:Terms]]
[[Category:Fighting Styles]]