Engineering Defense at Japan’s Mountain Castles

The Ichijōdani Asakura Clan Ruins in Fukui Prefecture.

The kuruwa at the ruins of Jōheiji Castle in Shiga Prefecture.

The horikiri at the ruins of Iimori Castle in Osaka Prefecture.

The kirigishi at the ruins of Shibushi Castle in Kagoshima Prefecture.

Curved earthwork walls at the ruins of Katsuga Castle in Kagawa Prefecture.

A kuichigai no koguchi entrance at the ruins of Matsuoyama Castle in Gifu Prefecture.

A semicircular umadashi at the ruins of Suwahara Castle in Shizuoka Prefecture.

Unejō tatebori at the ruins of Nagano Castle in Fukuoka Prefecture.

Horishōji at the ruins of Yamanaka Castle in Shizuoka Prefecture.

A high stone wall at the ruins of Kannonji Castle in Shiga Prefecture.

A wall made of large stones at the ruins of Iimori Castle in Osaka Prefecture.

Odani Castle in Shiga Prefecture, where stones for residences were discovered in an excavation, indicating that families lived there.