Yasutani Hakuun (1885–1973) was born in Japan during the Meiji era. Born into a poor family, he was adopted at the age of five and went to live in a country temple. He trained in many temples before starting a family at the age of thirty. At forty, he returned to the priesthood again, and eventually came to study with the Soto priest Harada Sogaku. Under this teacher, Hakuun's practice deepened, and he went on to teach monks and lay practitioners. He authored almost one hundred volumes of writings.