Mount Osore, Sacred volcanic mountain in Mutsu, Japan

Mount Osore is the name of a Sōtō Zen temple and pilgrimage site in the caldera of an active volcano in Mutsu, Aomori Prefecture. The caldera's highest peak, Kamafuse-yama, reaches 878 metres, and the ring of eight somma peaks encloses Lake Usori, a highly acidic caldera lake. Steaming fumaroles release sulfur dioxide among the bare rocks, and a small brook running to the lake is equated with the Sanzu River.

The Buddhist monk Ennin founded the Bodai-ji temple complex on the volcano in 862 and transformed the harsh landscape into a place of religious devotion. Since then, the site has drawn believers who come here to seek contact with deceased relatives.

The name Osorezan means Fear Mountain and reflects the traditional belief that souls of the departed pass through this place on their journey to the afterlife. Visitors find small stone piles along the pathways built by pilgrims in memory of children and decorated with colorful pinwheels.

Buses run from May through October from Shimokita Station to the temple grounds entrance and make the journey to this remote area easier. Paths lead over level ground around the lake but can become tiring due to sulfur fumes and rocky terrain.

The hot spring water leaves gold-rich deposits: sediment at Osorezan was found to contain over 400 grams of gold per tonne of ore, among the richest veins known worldwide. In 2007 the site was named one of Japan's Top 100 Geological Sites, but mining is banned because the area is a quasi-national park and the soil holds arsenic and hydrogen sulfide.