Built in: 1148 by Oyama Masamitsu
Oyama Castle is the ruins of castle located in southern Shimozuke (Tochigi). It is known as Gion Castle( 祇園城). Oyama castle, Nakakuki castle and Washi castle are registered as the national historic sites.
Record said, this castle was built in 1148 by Oyama Masamitsu. Oyama clan was originally from Ota clan, the descendant of Fujiwara clan. Masamitsu is the first Oyama moved in Oyama city. Oyama clan was Syugo Daimyo, feudal lord, in Kamakura period, but after the battle of Odawara in 1590, because Oyama clan fought against Hideyoshi, they lost their land and Oyama castle was abandoned in 1619.