Two soakers preparing step in the hot spring river. Four soakers including Onsen Soaker near upper right corner. Upper part of the river is frozen.
Located near the famous Kusatsu Onsen in Gunma Prefecture, the Shiriyaki Onsen(尻焼温泉), literally means "buttocks burning hot springs", is one of the rare onsens gushing from the bottom of the river and soakable entire width of the river year round in beautiful location. This in one of my most favorite onsens in Kanto Region.
A part of the Nagasasazawa-gawa or Nagasawazawa river, makes a large open-air bath, about 25 meters by 30 meters. If you watch carefully, you can see hot springs are gushing from the bottom. Temperature of the river water was 30-38°C last weekend. I found comfortable spot of around 38°C and soaked an hour and half. The air temperature was 3-4°C.
Clothing is optional. In the summer, many families visit and soak wearing swimsuits, bring tubes for swimming and other goods. Well, it looks like beach sides and I avoid to visit in mid summer.
In the winter, many male visitors soak in their birthday suites just hanging washing towels in front of their bodies. Ladies soak in swimsuits or in clothe for mixed baths, but there is no changing room and you have to change clothes in your car or public rest room nearby.
There is also an indoor bath at the riverside. Clothing prohibited in this bath. The water temperature here is warmer than in the river as hot springs directly piped in this bath.
There is only a few ryokans around without any kind of shops, you need to bring towels and other stuffs you may need.
If you're nature oriented, you'll like the Shiriyaki Onsen.
You can see the hot spring pool over the roof of the indoor bath.
◆Shiriyaki Onsen (尻焼温泉）
Type: Gender Mixed open-air bath.
Address: Kuni, Nakanojo-machi, Agatsuma-gun, Gunma Pref.
Location: 36.648460, 138.64791
Access: Almost all soakers visit with their own vehicles. If you want to visit with public transportation, take bus from Naganohara Kusatsuguchi Station of Agatsuma Line to Hanasiki Onsen (花敷温泉). There are only tree or four service a day for each way. You can walk to Shiriyaki Onsen from the Hanashiki in 15-20 minutes.
Available hour: Round the clock round the year. Sometimes the water level is too high to soak especially after heavy rain and snow melting season.
Admission fee: Free
Equipment: indoor bath
My rating (A-E): A
The red letters tell "Swim Suites Prohibited".
