Nasu

Nasu lies in northern Shimotsuke, where hills and river valleys lead toward the mountains of the northeast. Karasuyama Castle stood on a ridge above the Naka River and served as a stronghold of the Nasu family. After the family lost its lands in 1590, the castle passed rapidly among several lords. In 1725 Ōkubo Tsuneharu received the domain, beginning a long period of Ōkubo rule from Karasuyama.