, is a flatland-hilltop Japanese castle ruin located in Tokorozawa, Saitama Prefecture. It was on a key route between the northern Kanto Plain and Hachioji. The most recent structure was built in the 15th century by Ōishi Sadahisa and existed during the 16th century Sengoku Period of Japanese history. In 1546, the Hojo of Odawara took control and in 1569 possession passed to the Takeda. After 1590, the castle was abandoned simultaneously with the arrival of Tokugawa Ieyasu into the region, having outlived its purpose.