In a sense, the Fourth Patriarch is describing the two meanings of tso-ch'an in Ch'an. In the beginning the practitioner starts by taking the sitting posture. He will use simple and basic methods of regulating the body and mind. At an advanced stage, he will not be limited to sitting, but in any posture, his mind will be in accord with the Samadhi of One Act.

His disciple, the Fifth Patriarch Hung-jen 弘忍(602 -675), wrote an essay, Hsiu-hsing Yao Lun, 修行要論, The Essentials of Cultivation, which emphasizes sitting. He quoted from the I-chiao ching 遺教經, The Sutra of the Buddha's Last Bequest, which says "When the mind is placed at one point, there is nothing that cannot be attained." The one-pointedness of mind to which he referred was not samadhi, but one's original or true mind. He also said that correct posture is critical. Beginners should, for example, follow the Kuan wu-liang shou fo ching 觀無量壽佛經, Sutra of Contemplation on the Buddha of Unlimited Life, which says that one should sit upright with correct thoughts, closing one's eyes and mouth, and sit day and night. From many sources we can see that the Fifth Patriarch did sit a lot. The Biographies of Eminent Monks 高僧傳 describe the Fifth Patriarch foregoing sleep to sit all night. In the same book, Shen-hsiu 神秀(active 671-706), a disciple of Hung-jen 弘忍 and founder of the Northern Branch of the Ch'an School, is described as taking tso-ch'an as his main job.