Also known as Tendai Shinto, Hie Shinto, Sanno Shinto. A tradition of ritual, cosmology and art which developed within the esoteric Tendai tradition based at Mt. Hiei, whose guardian deity sanno 'mountain-king' was regarded as a manifestation or avatar (gongen) of Shakyamuni Buddha and identical with Amaterasu. Ichi-jitsu is a Buddhist expression meaning 'one reality' or 'one truth'. According to legend Saicho (Dengyo Daishi) was helped in his realisation of the true meaning of the Lotus Sutra (Hokkekyo) by the deity Sanno, protector of the Enryakuji temple-shrine complex. Twenty-one shrines on Mt Hiei are considered to be gongen of various bosatsu and buddhas. The main proponent of Sanno-ichijitsu-shinto was the Edo period monk Tenkai (Jigen Daishi, 1536-1643) who built the Nikko Toshogu to enshrine Tokugawa, Ieyasu according to Sanno ichijitsu rites.
A Popular Dictionary of Shinto. Brian Bocking.