[2] Shortly after the end of the Second World War, Nishijima received a law degree from Tokyo University and began a career in finance.

He was also a notable translator of Buddhist texts: working with student and Dharma heir Mike Chodo Cross, Nishijima compiled one of three complete English versions of Dōgen's ninety-five-fascicle Kana Shobogenzo; he also translated Dogen's Shinji Shōbōgenzō.

[4][5] While studying the Shōbōgenzō, Nishijima developed a theory he called "three philosophies and one reality,"[6] which presents his distinctive interpretation of the Four Noble Truths as well as explaining the structure of Dogen's writing.

The fourth perspective is reality itself, which Nishijima argues cannot be contained in philosophy or stated in words, but which Dōgen attempts to suggest through poetry and symbolism.

[1] Nishijima stated that "Buddhism is just Humanism"[7] and he explains Dogen's teaching on zazen in terms of balancing the autonomic nervous system.