Kannon-ji, Buddhist temple on Mount Mitsuishi in Kimitsu, Japan

Kannon-ji is a Shingon Chizan school temple on the summit of Mount Mitsuishi in Kimitsu, Chiba Prefecture. Its main hall, the Kannon-dō, stands below three large rocks that give the mountain its name, and the grounds around the summit are protected as the Mitsuishi-san Natural Forest, a prefectural natural monument.

The temple began in 1409 when the monk Kakue enshrined an Eleven-Faced Kannon statue in a rock cave on the summit of Mount Mitsuishi. The statue was lost when the cave collapsed but later reappeared, prompting the construction of the Kannon Hall in 1611. In 1873 the main image was moved to Zōfuku-ji at the foot of the mountain and the temple was abandoned, then revived in 1879.

The temple is commonly called Mitsuishi Kannon after the three large rocks at the summit. Its main images are an Eleven-Faced Kannon and a Yakushi Nyorai. Visitors leave handkerchiefs at the Oku-no-in behind the Kannon hall, reached through a gap in the rocks, to pray for a good match.

The temple stands on the summit of Mount Mitsuishi, reached by the paved Katakura-Mitsuishi forest road, which ends at the temple gate; the road is narrow, so large sightseeing buses cannot pass, and it becomes one-way during the New Year period. The front approach (omote-sando) runs from National Route 465 toward Kameyama Lake, while the rear approach (ura-sando) branches off the forest road and climbs a trail to the Kannon hall; its gate opens from 6:00 to 14:00. A ridge trail, the Mitsuishi footpath, leads from Mount Motokiyosumi via Jizo Pass to the gate.

Behind the Kannon hall, a path squeezes through a gap in the summit rocks to the Oku-no-in, where visitors leave handkerchiefs as votive offerings for help finding a marriage partner. The whole summit area around the temple is protected as the Mitsuishi-yama Natural Forest, a Chiba Prefecture natural monument.