yōgai 要害

Keywords
Architecture
Castles

Also written 用害.

1 A place of strategic importance, having steep terrain that is easy to defend. In the early medieval period, Japanese towns were built on plains and flatlands. In the event of an attack by a strong enemy, the people would withdraw to an easily defended strategic mountain yōgai san 要害山. The term is still used in Yamanashi Prefecture Kōfu 甲府 city, and in other parts of Japan.

2 A stronghold or fortress located at a strategic place.