Kasama Castle

Kasama Castle is a mountain castle built on the summit of Mount Sashiro (elevation 207 m) in Kasama City, Ibaraki Prefecture. It is traditionally said to have been built during the Kamakura period by Kasama Tokitomo (1203–1265), and the Kasama clan held it as their residence for approximately 380 years thereafter. It is notable among Kanto-region castles for its extensive stone walls, and on April 6, 2017, it was selected as No. 112 of Japan's "Continued 100 Fine Castles" (Zoku Nihon 100 Meijo) by the Japan Castle Association.

Founding Background

Kasama Castle was built during the Kamakura period as a stronghold on the summit of Mount Sashiro and was subsequently developed as the successive base of the Kasama clan. Throughout the medieval period, earthen defensive structures were expanded, making it one of the leading castles in the northern Hitachi Province.

Lords and Succession

The Kasama clan held Kasama Castle as their residence for about 380 years from the Kamakura through the Sengoku period. In 1590, during Toyotomi Hideyoshi's Siege of Odawara, the Kasama clan, who had sided with the Later Hojo, were destroyed, and a retainer of the Utsunomiya clan took the castle. In 1598, Gamo Gonari entered the castle and undertook renovation of the main approach road and the honmaru enclosure, advancing the transformation from a medieval mountain fortress into an early modern castle.

Structure and Defenses

Kasama Castle is highly regarded for retaining both medieval earthen fortifications and early modern stone walls. Stone walls are used extensively around the honmaru and along the main approach road, which is considered unusual for a Kanto-region castle. Earthworks and dry moats from the medieval period can also be observed throughout the site.

Current State and Preservation

Today, the summit area of Mount Sashiro is preserved as a castle ruin, retaining stone walls and earthworks. As one of the Continued 100 Fine Castles of Japan, it is maintained and interpreted by the local municipality.