Haunted by existential questions, at age 20 he entered Shogen-ji, a well-known Rinzai monastery; it is reported that he experienced kensho after two and half years there.

He eventually studied under various Sōtō-priests such as Harada Sodo Kakusho,[2] Oka Sotan, Akino Kodo, Adachi Tatsujun, Hoshimi Tenkai, and Rinzai-priests such as Unmuken Taigi Sogon and Kogenshitsu Dokutan Sosan, with whom he completed koan-study.

[citation needed] Harada Roshi's teaching integrated the Rinzai use of Kōan, a practice which was abolished in the Sōtō-school in the 19th century under influence of Gento Sokuchu (1729–1807).

This led ultimately to the spread of combined Sōtō and Rinzai methods by the Sanbo Kyodan (today Sanbo-Zen International), Zen-community founded by Yasutani which became influential in the West.

[note 1] Harada Rōshi may be viewed as an eclectically talented Sōtō teacher who did not abide by sectarian boundaries in regard to practice method.