Kūkai studied esoteric Buddhism in China, where he inherited the transmission from his teacher and returned to Japan to found the Shingon sect.

   He is revered by all Japanese as a poet, calligrapher, philosopher, and scholar. There is no evidence that Kūkai was directly responsible for creating hidden buddhas.      However, the phenomenon began to appear around the time Kūkai encouraged the view that the native Japanese kami were avatars of Buddhist deities.    In this way Japanese Buddhism absorbed elements of indigenous Shinto belief—this is also the thesis Philip espouses in the early days of his study of hidden buddhas.