Spirit Echoes (心滴拳聴, Shinteki Kenchō) is a martial arts term. It seemingly happens in abundance throughout the palace invasion, during the Chimera Ant crisis.
The term Spirit Echoes is used by some branches of martial arts to designate a peculiar phenomenon occurring when two truly powerful fighters engage in battle: their sense of the passage of time becomes often inconsistent with one another, and the two combatants manage to hear what the other is thinking at that moment, learning information that no one but the opponent could know. Zeno Zoldyck likened this phenomenon to a revolving lantern, and explained it is similar to when, in the instant before death, time seems to slow down and one's life flashes before their eyes, although he claimed it is easier to verify since both sides hear the other's thoughts, rather than their own.
In the Crunchyroll's translation of the 2011 anime adaptation, the term is translated as "Listening with the Spirit".
The name of this phenomenon is written with the kanji for "heart" or "mind" (心), "to drop" or "to drip" (滴), "fist" (拳), and "to listen" or "to hear" (聴). A possible literal translation of the term would be "Hearing Minds through Dripping Fists".