Castles in Japan were built to guard important or strategic sites, such as ports, river crossings, or crossroads, and almost always incorporated the landscape into their defenses. They evolved from the wooden stockades of earlier centuries, and came into their best-known form in the 16th century. Japanese castles ( 城, shiro or jō) are fortresses constructed primarily of wood and stone. Fortresses constructed primarily by stone or wood in earlier Japanese history Himeji Castle, a World Heritage Site in Hyōgo Prefecture, is the most visited castle in Japan.
