An eminent Ch'an figure in China who lent his name to one of the ‘Five Houses’ of Ch'an in the late T'ang period, and who appears in many kōans in the collections Gateless Gate and Blue Cliff Records. He left the householder's life at an early age, and spent time in conventional monastic life before taking to the road in the search for a higher level of truth. He studied with various masters, but attained enlightenment with one Mu-chou Tao-tsung, an eccentric disciple of the famed Ch'an master Huang-po Hsi-yün who practised an extremely ascetic life in the harsh mountain terrain of North China. Yün-men attained enlightenment under him when the teacher, responding to his request for teaching, threw him through the front gate and slammed it on his leg hard enough to break it. After this, he travelled south, taking up residence under the auspices of a local ruler on Mt. Yün-men near the city of Shao-chou in Kuang-tung Province; both he and the monastery that the rulers built for him took their names from this mountain. There, he taught many disciples using methods reminiscent of his own training–sharp blows, loud shouts, and paradoxical, one-word answers to questions. Using these methods, he tried to push students to see the nature of all aspects of reality and to transcend all dualities of pure and impure, enlightened and ignorant. He is perhaps most famous for answering the question ‘What is the Buddha?’ with a word that indicated a stick used to clean the anus after defecation, again showing that human concepts of ‘pure’ and ‘impure’ were mere constructs not reflecting the highest truth about things.