slations of Buddhist sutras that described methods for achieving a unified mind appeared around the second century A.D. During those early centuries many Chinese monks practiced zazen to achieve a unified mind in the Indian manner. Zazen was described in three aspects: regulating the body, breath, and the mind. Four methods were also presented: constant sitting; constant walking; half walking; half sitting; and neither walking nor sitting.
             Zazen most precisely refers to the means developed by the Ch'an masters to attain enlightenment. The two principal paths of Ch'an are the method of "silent illumination" and the method of the koan.
             The method of silent illumination may be traced back at least as far as Bodhidharma. Shih-shuang Ch'ing-chu (805-888) lived on a mountain called Shih-shuang for twenty years. His disciples just sat continually, even sleeping in this upright position. In their stillness they looked like so many dead tree
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