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 yougaisan 要害山. The term is still used in Yamanashi prefecture 
      Koufu 甲府 city, and in other parts of Japan. 
       
      2 A stronghold or fortress located at a strategic place.  |