The water from this spring are divided by three with a triangle stone. During Sengoku Period, Takeda Shingen put this stone and designed this dividing system for his farmers.
Sanbuichi Spring (三分一湧水, sanbuichiyusui) is the most famous Yatsugatake springs. It is located 1,000m high from the sea levels, and 8,500t of water springs everyday. This water is chosen as one of 100 best water in Japan.
Tourist Info.
Don't Drink this water because it is used for farming.
There is a parking, and gift shops. (9:00 to 17:00)
Access
0. at Obuchizawa Station
1. use JR Koumi Line to Kai-Koizumi (5 min.)
2. walk west (5 min.)
30 min
New Wave Samurai Movie. 
映画好き集まれ！ 
The water from this spring are divided by three with a triangle stone. During Sengoku Period, Takeda Shingen put this stone and designed this dividing system for his farmers.