Saichō (also known from his posthumous name as Dengyō Daishi, 767–822). Japanese Buddhist monk and founder of Tendai. Together with Kūkai, he was one of the two leading figures in the Heian (‘peace and tranquillity’) period in Japan. In 804, he went to China, to study Tʾien-tʾai, and to gain sanction for the new foundation on Mount Hiei. He did not intend to introduce, still less found, a new school, and for some time he applied himself to esoteric Buddhism as much as to Tʾien-tʾai. When he returned to Japan in 805, he endorsed both as a kind of middle way between the Nara sects, Sanron and Hossō. His endeavours to incorporate esoteric Buddhism were overshadowed by the brilliance of Kūkai, and after an early friendship, relations between the two deteriorated. The incorporation of esoteric Buddhism was accomplished by Saichō's disciples, Enchin and Ennin. Saichō spent the last six years of his life trying to establish Tendai as the true Mahāyāna, and as the ‘protector of the nation’.

During this last period, Saichō composed his major works (including Shugo-kokkai-shō (Treatise on the Protection of the State), Hokke-shūku (Superlative Passages of the Lotus Sūtra), and Kenkai-ron (Treatise on the Precepts), in which he argued that Tendai was superior to other forms of Buddhism. He regarded his time as the period of Spurious Dharma (zōmatsu), and that only in Tendai would the people find guidance. A complex of many temples was established on Mount Hiei, but most (along with the major temple) were destroyed in 1571/2. Enryaku-ji was rebuilt on the mountain-top in the 17th cent. The main hall (Konpo-Chudo, 1643) is the third largest wood building in Japan.