The original meaning of koan (“koh-on”) in Chinese was “public case” — a case that established a legal precedent. In Zen a koan is a formulation, in baffling language, pointing to ultimate truth. Koans cannot be solved by recourse to logical reasoning but only by awakening a deeper level of the mind beyond the discursive intellect. Koans are constructed from the questions of disciples of old, together with the responses of their masters, as well as from portions of the masters’ sermons or discourses, from lines of the sutras, from other teachings and even from popular folk tales and poetry.
The word or phrase into which the koan distills itself, when taken on as one’s spiritual practice, is called in Japanese the wato (Chinese, hua t’ou). Thus, “Has a dog the Buddha-nature?” together with Joshu’s answer, “Mu!” constitutes the whole koan; the wato is simply “Mu!”
Altogether there are said to be 1,700 koans. Of these, Japanese Zen Masters use a core of 500, more or less, since many are repetitive and others less valuable for practice. Masters have their own preferences but invariably they employ (if they employ koans at all) two koan collections, the Mumonkan and the Hekigan-roku (Blue Cliff Record). At the end of one’s formal training one works in depth with the Jujukinkai, a series of koans on the 16 Buddhist precepts.
Koans should be studied experientially (not intellectually) with a trusted teacher who has gone through koan training themselves. Both of the Windhorse teachers, Sunya-roshi and Lawson-roshi, offer koan training at our training center just outside of Asheville, North Carolina.