Tage Castle was located at the top of Mt. Tage about 7 km to the northeast of the central part of Utsunomiya City, Tochigi Pref. It was built in the middle ages as a branch castle of Utsunomiya Castle, which was the base to control the North Kanto region. In the late Warring States period, the Utsunomiya clan improved it into a large-scale fortress as well as the military base against the Hojo clan’s gaining power in the Kanto region. Utsunomiya Kunitsuna, the 22nd generation head of the clan, joined Hideyoshi’s invasion of Korea, by which he was allowed to assume the surname of Toyotomi and ranked as Ju-Goi-no-ge (the fourteenth rank out of 30 ranks). However he was suddenly subject to punishment of “kaieki (confiscation of all the property)” and exiled to Bizen province (present-day Okayama Pref.), by which the Utsunomiya clan, one of the most powerful clans in Kanto region, was destroyed and Tage Castle was abandoned. With a lot of moats, earthworks, kuruwa (outer compounds) set out in the whole mountain, Tage Castle was constructed with all the strength of the Utsunomiya clan and it is said to have been one of the best castle in the Kanto region.