Yamanashi Prefecture is a prefecture of Japan located in the Chûbu region of the island of Honshû. The capital is the city of Kôfu.
Yamanashi Prefecture is bordered by Tokyo, Kanagawa, Saitama, Shizuoka, and Nagano. The prefecture is landlocked, with mountains surrounding the central Kôfu Basin. Mount Fuji is located on the southern border with Shizuoka. Mt. Fuji provides rain shadow effects, and as a result, the prefecture receives only about 818 mm of rainfall a year.