According to a theory, he became a priest with a second name of 'Zuifu', and studied Tendai Sect under Koshun in Kokawa-dera Temple (Utsunomiya City) of Utsunomiya Castle, Shimotsuke Province at the age of 14, then he studied further in Enryaku-ji Temple on Mt. Hiei and Enjo-ji Temple in Omi Province and Kofuku-ji Temple in Yamato Province.
一説に「随風」と号して出家した後、14歳で下野国宇都宮城の粉河寺(宇都宮市)の皇舜に師事して天台宗を学んだ後、近江国の比叡山延暦寺や園城寺、大和国の興福寺などで学を深めたという。