Born in 1173 in Kii Province, his dharma name was Kōben; he is also known as Myōe Shōnin and the Toganoo Shōnin. Orphaned young, he took vows at Jingoji on Mt. Takao. He developed a unique synthesis of Kegon and Shingon esotericism called "gonmitsu." In 1206, Emperor Go-Toba granted him the Toganoo site where he founded Kōzanji. From age nineteen he kept a dream diary for some forty years — the Yumeki, an extraordinarily rare document in world literature. He wrote Zaijarin criticizing Hōnen's exclusive nenbutsu and worked to revive monastic precepts. He also began cultivating tea at Toganoo from Song Chinese stock, contributing to the development of Japanese tea culture. He died in 1232 at age sixty.

A pure ascetic with a mystical sensibility drawn to the dream world. While strict enough to criticize Hōnen on doctrinal grounds, he also showed deep affection for nature and animals — a quality linked to Kōzanji's famous Chōjū Giga scrolls.

Kōzanji is a UNESCO World Heritage Site; its Chōjū Giga scrolls are a national treasure considered the origin of Japanese manga. The Yumeki draws attention in psychology and religious studies as a globally rare dream record. Tea cultivation at Toganoo is considered the origin of Uji tea.