This dissertation examines the relationship between the revival of the study of Tendai doctrine and the concurrent institutional reformation of Japanese Tendai led by Ryogen (912-985) the eighteenth abbot of Enryakuji, during the tenth century. When Ryogen entered Enryakuji on Mount Hiei in 923 as a novice, the practitioners devoted little effort to the study of Tendai doctrine that was the basis for their meditative practices. After the founder Saicho (767-822) died, doctrinal studies had been progressively disregarded. Further, institutional secularization led to an erosion of monastic discipline during the early Heian period (794-1191). As a scholar and administrator, Ryogen rekindled interest in the study of Tendai doctrine and initiated institutional reform during his tenure as abbot of the Tendai school (966-985).
The ingenuity of Ryogen's leadership as the abbot of Enryakuji lay in his vision integrating doctrine and institution. In order to restore institutional integrity and revitalize the study of doctrine, Ryogen emphasized three Mahayana Buddhist ideas, one vehicle (ichijo or ekayana), buddha-nature (bussho), and bodhisattva precepts (bosatsukai). Although Tendai masters before Ryogen also appreciated these ideas, Ryogen promoted Tendai's unique interpretations of one vehicle, buddha-nature, and bodhisattva precepts, and applied these ideas institutionally by means of doctrinal debates, public lectures, and communal rituals.
Instead of relying on his charisma, Ryogen institutionalized these ideas to instill in his community a renewed sense of identity and to articulate its distinctiveness from other Buddhist schools. Under Ryogen's leadership, Japanese Tendai developed into the largest and most influential Buddhist community in Japan with a community of three thousand priests residing on Mount Hiei. Ryogen's efforts established the foundation for the doctrinal and institutional traditions that emerged during the Kamakura period (1192-1333). Founders of the Kamakura Buddhist movements, such as Honen (1133-1212), Dogen (1200-1253), Shinran (1173-1262), and Nichiren (1222-1282), all emerged from the Tendai school reformed by Ryogen. At Enryakuji Ryogen is remembered as the "second founder of Mount Hiei (Eizan chuko no so)."
