Ishin-denshin (以心伝心) is an idiom[1] commonly used in East Asian cultures, such as in Japan, Korea and China, which denotes a form of interpersonal communication through unspoken mutual understanding.
Although mutual silent understanding is a universal human phenomenon, there is a widespread belief in Japan that such a form of non-verbal communication is a defining characteristic of national culture (in the mindset of nihonjinron[4]).
[5] The introduction of this concept to Japan, via China, is related to the traditions of Zen, where the term ishin-denshin refers to direct mind transmission of Buddhist dharma.
[5][6] According to Zen tradition, the concept of ishin-denshin can be traced back to the initial dharma transmission between Gautama Buddha and Mahākāśyapa related in the Flower Sermon.
[7][8] The belief that ishin-denshin is essential to interpersonal communication continues to influence aspects of contemporary Japanese culture and ethics,[9] ranging from business practices[10] to end-of-life care.