Amihari Onsen, Shizukuishi, Iwate Prefecture
Sennyo-no-Yu Hidden Open-Air Bath
A seasonal mixed-gender rock bath beside a forested stream, best for visitors comfortable with a short trail and very basic facilities. It closes for rain and winter, and the 2026 season is scheduled to end on November 3.
Check before bathing
- Opening hours
- For the 2026 season, planned May 12–November 3, day use is 10:00–15:00 with last reception at 14:00. Admission is ¥700 for guests of elementary-school age and older. Rain can stop operations; weather, snow or repairs may shorten the season. Pay at the main building, then walk about 7 minutes along a mountain path. No shower, shampoo or keyed locker. A bathing wrap is available for ¥700, or bring your own. Photography is prohibited.
- Tattoo policy
- Tattoos that cannot be fully covered are not permitted.
Spring & water temperature
- Spring-source temperature
- About 73°C for the Motoyu source; this is not the temperature of Sennyo-no-Yu.
- Bathing temperature
- No fixed pool temperature is published.
- Spring source
- Amihari Onsen Motoyu, on the former crater side of Mt. Inukurayama; the current facility page does not give a formal source-well name.
- Spring classification
- Amihari Onsen system: simple spring / simple sulfur spring, including hydrogen-sulfide-type water.
- pH
- 4.1 for Amihari Onsen overall, according to the operator.
- Flow rate
- Not published.
- Water handling
- The operator describes the Amihari system as source-flowing and says this bath draws from the same source system. Full treatment details for this individual outdoor pool are not published.
This is one mixed-gender outdoor rock bath beyond separate changing huts. Rain, winter closure and other weather or repair issues can interrupt the planned season. There is no shower or keyed locker; wear a bathing wrap if preferred, and do not take photographs.
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.
