Kai Province

Kai Province (甲斐国 Kai-no-kuni) was a province of Japan in the area of Japan that is today Yamanashi Prefecture. Kai bordered on Sagami, Suruga, Shinano and Musashi Provinces. Its abbreviated form name was Kōshū (甲州). The origin of its name is uncertain. It lies in central Honshū, west of Tokyo, in a landlocked mountainous region that includes Mount Fuji along its border with modern Shizuoka Prefecture.