Château de Takamishiro, Mountain castle in Ogawa, Saitama Prefecture, Japan

Takamishiro is a medieval Japanese mountain castle (yamajiro) on Mount Yotsuyama in Ogawa, Saitama, about 3.5 km north of Ogawa-machi Station. The summit, 197 m above sea level and 100 m above the surrounding land, was entirely fortified across roughly 174 m north to south and 54 m east to west. Three enclosures line the ridge: Sannokaku, Ninokaku and the honmaru at the highest point, now the site of Yotsuyama Shrine.

The castle's origin is unknown, but the Aoki family records state that Ishii Kurozaemon Masatsuna, a retainer of the Aoki clan, lived here in 1180. By the Sengoku period the Masuda clan held it, and it became a branch castle of Hachigata Castle on the Yamanouchi Uesugi side. In 1488 it guarded the rear of the Uesugi force at the first Battle of Takamigahara, and it was used again in 1494.

The summit holds Shitsuzan Shrine, built on the honmaru, the highest point of the ridge. The castle is also called Shitsuzan Castle after this hill. The north side is thought to have been the rear entrance (karamete-guchi) and the south the main gate (ote-guchi).

The mountain can be accessed via marked trails, with pathways leading to the main areas, though some sections are steep. Visitors should wear comfortable shoes and allow plenty of time to explore different parts of the site.

The summit holds Shitsuzan Shrine, and the castle's name is also read Shitsuzuyama-jō. The site stretches about 174 m north to south and 54 m east to west, with three enclosures in a row: Sannokaku, Ninokaku and the honmaru at the highest point. The north side is thought to have been the rear entrance, the south the main gate.