In 10th century, due to the collapse of ancient administrative system and rise of local samurai bands, the central government abandoned direct rule in favor of a feudal system of local warlords nominally under the control of various nobles in Kyoto. Taga Caste gradually fell into ruins, and rise of Hiraizumi under the Northern Fujiwara in the twelfth century saw its final demise. During the Nanboku-chō period, Kitabatake Chikafusa and his son Kitabatake Akiie briefly occupied the site for the Southern Court, but later moved to the more secure mountain fortress of Mount Ryōzen to the north. The site reverted to empty fields, and was not excavated until 1955, with more extensive investigations in 1976.