Sakura at Lake Shibire (四尾連湖の桜) is very nice. There are about 20 Sakura surrounding the lake. It blooms around the middle of April.
Tourist Info.
There is parking and restroom.
There is camping feild.
Access
Need a car.
0. at Kofuminami exist of Chuo line.
1. use 140 to 3.
2. change 409 to the lake.
30 min
New Wave Samurai Movie. 
映画好き集まれ！ 
Lake Shibire is a Caldera lake located in the middle of Yamanashi Prefecture. It is a small lake surrounded by the beautiful nature that has a beautiful Koyo in Autumn. The altitude of the lake is 880m from the sea level. The size is about 1.2km long round and many people visit here for hiking, camping and boat riding.