At the age of 12 he began his Buddhist study at a temple of the Tendai school, Seichō-ji (清澄寺, also called Kiyosumi-dera).: He was formally ordained at sixteen years old and took the Buddhist name , Renchō meaning Lotus Growth. He left Seichō-ji for Kamakura where he studied Pure Land Buddhism, a school that stressed salvation through nianfo (Japanese nembutsu) or the invocation of Amitābha (Japanese Amida), and then studied Zen which had been growing in popularity in both Kamakura and Kyoto. He next traveled to Mount Hiei, the center of Japanese Tendai Buddhism, where he scrutinized the school's original doctrines and its subsequent incorporation of the theories and practices of Pure Land and Esoteric Buddhism. In the final stage of this twenty-year period he traveled to Mount Kōya, the center of Shingon esoteric Buddhism, and to Nara where he studied its six established schools, especially the Ritsu sect which emphasized strict monastic discipline.: