Hirano, Lake Yamanaka, Yamanashi
Yamanakako Hirano Onsen Ishiwari-no-Yu
A useful stop on the east side of Lake Yamanaka after hiking Mount Ishiwari, with a sauna and a quiet timber-built setting. The operator lists several natural-spring pools but does not publish treatment details for each one. Tattoos are not admitted.
Check before bathing
- Opening hours
- As listed for September 2026: 11:00–19:00, last admission 18:15; adult admission ¥900. The latest monthly notice lists Thursdays as closing days. Check the current calendar before travelling.
- Tattoo policy
- Tattoos, tattoo stickers and similar coverings are not admitted.
Spring & water temperature
- Spring-source temperature
- An exact figure is not published; the operator classifies it as a low-temperature spring.
- Bathing temperature
- No fixed pool temperature is published; a separate source-water lukewarm pool is available.
- Spring source
- Ishiwari-no-Yu spring.
- Spring classification
- Alkaline simple spring; hypotonic, alkaline and low-temperature.
- pH
- 10.2.
- Flow rate
- Not published.
- Water handling
- The operator lists natural spring water in the main bath, reclining bath, source-water lukewarm pool and outdoor rock and cypress baths. Current pages do not give complete pool-by-pool dilution, heating, circulation or disinfection details.
A temporary closure in April 2026 ended with reopening on April 29; the September schedule lists Thursday closures.
How to read a bath profile
Spring-source temperature and actual bathing temperature are kept separate. Each score is shown independently for comparison rather than collapsed into one overall score.
