Ishin-denshin (以心伝心?) is a Japanese idiom which denotes a form of interpersonal communication through unspoken mutual understanding. This four-character compound, known as a yojijukugo, literally translates as "what the mind thinks, the heart transmits." Sometimes translated into English as "telepathy" or "sympathy", ishin-denshin is also commonly rendered as "heart-to-heart communication" or "tacit understanding."
Although silent understanding is generally recognized as a universal human phenomenon, the term ishin-denshin is often used to convey a style of nonverbal communication between two people that is felt to be characteristic of Japanese culture. Whereas the Japanese concept of haragei denotes a deliberate form of nonverbal communication, ishin-denshin refers to a passive form of shared understanding. Ishin-denshin is traditionally perceived by the Japanese as sincere, silent communication via the heart or belly (i.e. symbolically from the inside, uchi), as distinct from overt communication via the face and mouth (the outside, soto), which is seen as being more susceptible to insincerities. Such concepts are related to the traditions of Zen, where the term ishin-denshin refers to direct mind transmission.
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