Enryaku-ji  is a Tendai monastery located on Mount Hiei in Otsu, overlooking Kyoto. It was founded in 788 during the early Heian period (794-1185). The temple complex was established by Saicho (767–822), who introduced the Tendai sect of Mahayana Buddhism to Japan from China. 

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 (Kyoto, Uji and Otsu Cities)". The founders of Buddhist sects all spent time at the monastery. 

Today, most of Enryaku-ji's buildings are clustered in three areas. The monastery's most important buildings are concentrated in To-do. Sai-to is a 20-minute walk away, primarily downhill from To-do, and also features several important buildings. Yokokawa is more isolated and less visited.