Tenzai Castle

Tenzai Castle [星勢莽; てんざい・がり] is a castle located in the city of Tenzai in Heisai Prefecture. It is believed to have been constructed in the late 12th century, and used as the headquarters of the Tengō clan, who governed the majority of the region.
Located near the southern banks of Lake Ōtsuke, the castle was intended to serve as a watchtower and keep for invading forces arriving from the south. During the Battle of Heigen in 1389, during which the Tengō fought against the Daito clan of modern-day Kigen Prefecture, Tenzai Castle played quite a vital role.