Sokushin zebutsu (), rendered in English as Mind is Itself Buddha, is a book of the Shà Âbà Âgenzà  by the 13th century Sà Âtà  Zen monk Eihei Dà Âgen. It was written in the spring of 1239 at Dà Âgen's monastery Kà Âshà Âhà Ârin-ji in Kyoto. The book appears as the fifth book in both the 75 and 60 fascicle versions of the Shà Âbà Âgenzà Â, and it is ordered sixth in the later chronological 95 fascicle Honzan editions. The title Sokushin zebutsu is an utterance attributed to the 8th century Song Dynasty Zen monk Mazu Daoyi in a well known kà Âan that appears most notably as Case 30 in The Gateless Barrier, although Dà Âgen would have known it from the earlier Transmission of the Lamp. In addition to this book of the Shà Âbà Âgenzà Â, Dà Âgen also discusses the phrase Sokushin zebutsu in several of his formal Dharma Hall Discourses, namely numbers 8, 75, 319, and 370, all of which are recorded in the Eihei Kà Âroku.
Dà Âgen's book Sokushin zebutsu lays out his understanding of this phrase, rendered in English as mind is itself Buddha. He quickly notes that he views as incorrect the interpretation that the "ordinary thoughts and awareness of sentient beings" are already Buddha. He states that instead, "Sokushin zebutsu is buddhas of aspiration, practice, awakening, and nirvana. Those who have not actualized aspiration, practice, awakening, and nirvana are not sokushin zebutsu.â While aspiration, practice, awakening, and nirvana are a version of the four stages of enlightenment and are normally thought of a series of steps one must go through to achieve a final goal, Dà Âgen writes in the Shà Âbà Âgenzà  book Gyà Âji, "Where aspiration is present, there is already practice. Practice is itself awakening. This practice-awakening is nirvana. Thus âÂÂaspiration, practice, awakening, and nirvanaâ are not sequential stages. All are one." Thus, for Dà Âgen, sokushin zebutsu is identical to practice, or zazen. Further, at the conclusion of the essay, Dà Âgen writes, âÂÂThe buddhas spoken of here are none other than Shakayamuni Buddha. Shakyamuni Buddha is sokushin zebutsu. When all buddhas in the past, present, and future are buddhas, they unfailingly become Shakyamuni Buddha". Dà Âgen thus equates mind, Buddhas, Shakyamuni Buddha, Bodhicitta, practice or zazen, awakening, and enlightenment, offering a characteristic teaching in nondualism.