Koyama Castle

Yoshida, Shizuoka, Japan, Japan

---

Kōyama Castle is a Sengoku‑period hilltop castle in the Kataoka area of Yoshida‑chō, Haibara District, Shizuoka Prefecture, Japan, whose ruins are designated as a local historic site and which today features a modern concrete reconstruction of a main keep that functions as a museum and tourist landmark.

The original fort on the site was held by the Imagawa until they were defeated by Takeda Shingen; in 1571, under Takeda’s command, Baba Harunobu built Koyama Castle here, with Okuma Tomohide as its first lord, and the castle became an important node in the Takeda network of castles for the campaigns against Takatenjin Castle, serving both as a control point for the region and as a staging and supply base for those attacks.

Koyama Castle fell to Tokugawa Ieyasu’s forces in 1582, was never rebuilt in its original form, and gradually returned to ruin, while the site was later recognized as a Yoshida Town historic site and developed with a reconstructed “mock” main keep in 1987, modeled more on Inuyama Castle than on the actual design of the original Koyama Castle.