One of the two founders of the Ts'ao-tung school of Chinese Ch'an Buddhism. A quiet man of studious temperament, he received a basic education in the Confucian (see Confucianism) classics in his youth, and continued Confucian studies even after joining the Buddhist monastic order at the age of 16. He studied briefly with Tung-shan Liang-chieh, the other founder of Ts'ao-tung, and received from him the dialectical teaching of the Five Ranks. He was not inclined to travel, and spent 30 years living on Mt. Ts'ao (hence his title ‘Ts'ao-shan’). Although his own line of disciples died out in four generations, his systematization of the Five Ranks became his lasting legacy to the development of Ts'ao-tung thought and practice.