Yashima Castle Site

Yashima Castle was built in 667 as part of a defensive network guarding against potential invasion by Tang China and Silla, an attack that never came. Mentioned in the Nihon shoki but not physically identified until 1998, it was built in a Korean fort style with roughly six-meter-high stone walls. About 90 percent of the perimeter used natural ridges and rock formations, with only 10 percent artificially constructed. The restored southern gate sits 2.5 meters above the approach and requires a ladder to enter, with a second entrance at right angles creating a defensive bottleneck. Some modern hiking trails on Yashima follow what were once fort ramparts.