Kozan-ji Temple (GPS: 35.06025, 135.67853) is a Omuro Buddhist temple in the Takao district in Ukyo-ku, Kyoto. Officially known as Toganoo-san Kozan-ji, the temple is located deep in the mountains behind Jingo-ji Temple. The mountains are famous for their beautiful autumn leaves, and is regarded as ideal for mountain asceticism. In addition to Kozan-ji, the mountains are also home to other temples including the Toganoo-ji and Toganoo-bo.
The establishment of Kozan-ji Temple goes back to around AD 1206, when a Kegon Buddhist monk who had served at Jingo-ji Temple, was given permission to establish it by the Emperor Go-Toba. He originally named the temple Hiidetemazukouzanwoterasuyama-no-tera, deriving it from the Avatamsaka sutra. It means "Temple of when the sun appears, it first casts its light on the highest mountain".
At the Jingo-ji Temple is a diagram of the Kozan-ji, drawn in 1230. That was about twenty years after it was constructed, and the diagram is now an Important Cultural Property of Japan. The Kozan-ji Temple itself is home to numerous National Treasures of Japan and Important Cultural Properties of Japan, many of which are on loan to national museums in Kyoto and Tokyo.