Yamanakako Hirano Onsen Ishiwari no Yu

Ishiwari no Yu is a day-use hot spring facility at the foot of Mt. Ishiwari in Hirano, Yamanakako Village, Yamanashi Prefecture. It opened in July 1996 as the village's hot spring facility. The domed building makes generous use of cypress and chestnut wood, and the baths and a large tatami rest hall are arranged around a courtyard.

The water is an alkaline simple hot spring with a strongly alkaline pH of 10.2. The source, named Hirano Onsen, emerges at 26.5 degrees Celsius at 185 liters per minute, with 221.8 mg/kg of dissolved solids. The water is clear, tasteless and odorless, and feels slippery on the skin. The main bath is kept at around 41 degrees Celsius, and there is also a lukewarm source bath.

The facility offers an indoor main bath, an outdoor rock bath, an outdoor cypress bath, a reclining bath, a sauna and the lukewarm source bath. Admission is 900 yen for adults, 700 yen for junior high and high school students and 350 yen for elementary school children; preschoolers enter free. Guests with tattoos are not admitted. There is no lodging, and the facility is for day-use bathing only.