Ōya-ji(大谷寺) is a Buddhist temple of the Tendai sect in the city of Utsunomiya, Tochigi Prefecture, Japan. According to legend, the temple was established by Kūkai, the founder of the Shingon sect, in the year 810, but this has not been firmly established. The temple was rebuilt during the years 1615 to 1624. The temple is built into the surrounding tuff rock and features a carved figure of the BodhisattvaKannon with a thousand arms with a surrounding altar. Adjacent to the altar is another cave wall with a carving of the Buddhist trinity of Amida Buddha, Kannon and Seishi Bodhisattvas.
The temple complex also features a small museum of artifacts recovered from nearby settlements dating back to the Jōmon period in Japan. Across from the temple is a quarry that has been converted into a park. The park features a massive statue of Kannon Bodhisattva, called the "Kannon of Peace" (平和観音,heiwa kannon) carved after World War II.