Enryaku-ji is a Tendai monastery located on Mount Hiei in Ōtsu, overlooking Kyoto. It was first founded in 788 during the early Heian period (794–1185) by Saichō (767–822), also known as Dengyō Daishi, who introduced the Tendai sect of Mahayana Buddhism to Japan from China. The temple complex has undergone several reconstruction efforts since then, with the most significant taking place in 1642 under Tokugawa Iemitsu. Enryaku-ji is the headquarters of the Tendai sect and one of the most significant monasteries in Japanese history. As such, it is part of the UNESCO World Heritage Site "Historic Monuments of Ancient Kyoto ". The founders of Jōdo-shū, Jōdo Shinshū, Sōtō Zen, and Nichiren Buddhism all spent time at the monastery. Enryaku-ji is also the center for the practice of kaihōgyō.

Tendai , also known as the Tendai Lotus School, is a Mahāyāna Buddhist tradition with significant esoteric elements that was officially established in Japan in 806 by the Japanese monk Saichō. The Tendai school, which has been based on Mount Hiei since its inception, rose to prominence during the Heian period (794–1185). It gradually eclipsed the powerful Hossō school and competed with the rival Shingon school to become the most influential sect at the Imperial court.