Daisen, is a volcanic mountain located in Tottori Prefecture, Japan. It has an elevation of 1,729 metres. This mountain is the highest in the Chugoku region, and the most important volcano on the Daisen volcanic belt. The Daisen volcanic belt is a part of Southwest Honshu volcanic arc, where the Philippine Sea Plate is subducting under the Amurian Plate.
Daisen is a complex volcano, made by repeated volcanic activity over thousands of years. Eruptions in this area started 1.8 million years ago and resulted in Old Daisen some 500,000 years ago. The Daisen of today, New Daisen, resulted from a second group of eruptions which started 50,000 years ago and ended 10,000 years ago in the caldera of Old Daisen. 50,000 years ago, this mountain had a plinian eruption from which volcanic ash can be found as far away as the Tohoku Region of Japan. This mountain is one of the 100 famous mountains in Japan, and also one of the Chugoku 100 mountains.
Daisen, which stands directly on the Sea of Japan, was regarded as one of the most important mountains for Japanese Shugendo. According to the Izumo Kokudo Fudoki, completed in 733, this mountain was called Ōkami-take, literally, Mountain of the great god.
Daisen has been called Hoki Fuji and Izumo Fuji, depending on which side of the mountain the viewer is standing on. These names are based on the old Hoki and Izumo provinces.
In the middle of the mountain, there is a Buddhist temple, called Daisen-ji. This temple has existed as a centre of worship since the Heian-era. The temple was founded by the Tendai sect in 718.
Climbing the mountain used to be severely prohibited without a selected monk of Daisen-ji, and common people could not access the mountain until the Edo-era.
The mountain has also been important to the mountain ascetics of the Shugendo sect. Just above the temple is the Ogamiyama Jinja, literally, shrine of the mountain of the great god.