The temple's name comes from the mountain's shape, which resembles the armor (甲) of Bishamonten. A statue of this warrior deity still sits in the cave where the temple originally began 1,200 years ago.

Koyama-ji는 시코쿠 88개소 순례길의 제74번 사찰로, 헨로 순례자들의 필수 참배지입니다.

Kobo Daishi prayed at the Bishamonten cave for the safe completion of Manno-ike Reservoir renovations. The project finished in just three months, and this temple was built to commemorate that achievement.

Koyama-ji는 약사여래(약사불)와 관련이 있으며, 이곳에서 본존불로 모셔지고 있습니다.