Treasure House (Hōzō)
The Treasure House is where the monks kept their relics and valuable ceremonial implements. It is the oldest surviving building in the temple, dating to the end of the Heian period (794–1185), though parts of the building may be even older. Protected by a moat and heavy doors, the Treasure House is said to have stymied Ishikawa Goemon (1558–1594), a legendary burglar renowned for his ninja-like skills.
A small frog has been carved into a rock in the middle of the moat, near the bridge on the western side. It is an allusion to a famous story about the courtier and calligrapher Ono no Michikaze (894–966). While walking in the rain, Michikaze saw a frog trying to jump onto a willow tree. The frog failed repeatedly until it finally managed to grasp a branch. Michikaze took this as a sign about the importance of persistence. The story is depicted on traditional hanafuda playing cards and inspired a scene in a kabuki play.