Yamanashi is a prefecture in Japan . The Yamanashi prefecture is surrounded by 5 other prefectures Tokyo prefecture , Kanagawa Prefecture , Saitama Prefecture , Shizuoka Prefecture , and the Nagano Prefecture and is located in the ChÅ `` bu region of the island of HonshÅ `` . Yamanashi Prefecture is a prefecture of Japan located in the ChÅ `` bu region of the island of HonshÅ `` .