“Xin” is the literal meaning of the Chinese character “xin,” which implies the core, nature, essence of a person. Another set of meanings of this word is connected with the concept of faith: “xin” means the ability to inspire trust, to be indisputable, obvious. Thus, “xin” is the obvious, directly perceivable core of a person’s being—a phenomenal reality found behind the word “I.”
“Trust in the heart (xin-xin)” is what one of the later Zen patriarchs, Linji (Japanese: Rinzai, died 866), called “faith in oneself” (zi-xin). This is the only thing that allows a person to overcome dependence on other people’s authority and external conventions, to lean on one’s own strength, and not to seek enlightenment outside oneself, outside one’s consciousness.
In European languages, the term “xin” is usually translated as “mind,” “reason,” “soul,” “spirit,” “consciousness,” and “heart.” The most adequate seems to be a combination of the last two options.
The central moment of Zen Buddhism is the assertion of the identity of heart (xin) and nature (xin) of the human being. “Xin” refers to the natural qualities of things—inner qualities inherent to them as forms of manifestation of the universal natural process, “the flow of things,” the Path (dao). Human nature is one with the nature of things, which is why “the Great Path is not difficult”: one only has to trust one’s heart, follow one’s nature—and, as Linji says, “not to seek anything special.” Here are two translation variants.