What is samādhi? Though Indian tradition defines nine levels of samadhi, each with its own identifying characteristics, a general definition will suffice here. Samadhi is a unified state of mind in which there is no distinction between self and environment, no sense of time or place. This is not a state of no-thought or no-mind, since there is still an awareness of the self experiencing samadhi. Rather, it is a state of one-thought or one-mind. In Ch'an, an important distinction is made between samadhi and enlightenment, as seen in the spiritual path of Shakyamuni Buddha. After years of austere practice as a yogi, Shakyamuni had attained the highest level of samadhi, but he knew that his realization was still incomplete. He sat under the bodhi tree, vowing not to get up until he had fully resolved the question of death and rebirth. Only when he became enlightened, after seeing the morning star, did he rise. His experience became the paradigm of zazen practice.

The First Patriarch of Ch'an, the Indian monk Bodhidharma, reached China around A.D. 520 and established himself in Shaolin temple. While the historical facts of Bodhidharma's life are scant, there is little doubt that he was enlightened before arriving in China. Even so, he continued zazen practice. According to legend, Bodhidharma sat facing a wall for nine years, in the same posture used by previous masters to attain samadhi. However, he did not use Hinayana methods (such as visualizing parts of the body), and his goal was different--to attain liberation without necessarily going through samadhi. Bodhidharma's great contribution to Ch'an was his insistence on directly experiencing Buddha-nature through zazen.