intensive zazen meditation on a subject; knocking all into one
Buddhist term for a state of deep, unified concentration in zazen where subject and object become one. Literally 'striking all into one piece'.
See also: 座禅 (ざぜん)
In zazen practice, reaching the state of 'knocking all into one' is not easy.
The master used the phrase 'dajō ippen' to teach discarding distracting thoughts and concentrating on a single object.
座禅 is the general practice of seated meditation, while 打成一片 refers specifically to the intense, unified state achieved within that practice.
A yojijukugo of Chinese origin, literally 'strike become one piece'. The exact historical derivation is uncertain, but it is used in Zen Buddhism to describe a state of complete absorption.