Sainokawara Open-Air Bath

Sainokawara Open-Air Bath is an outdoor hot spring bathing area inside Nishinokawara Park in Kusatsu, one of Japan's well-known hot spring towns in Gunma. The combined men's and women's bathing areas cover roughly 500 square meters, making it one of the larger open-air baths in the country. Bathers soak in large tubs surrounded by forest, with views that change with the seasons, from fresh greenery to autumn colors to snow.

The bath draws on Kusatsu's natural hot spring source, and the setting is built around the idea of long, unhurried soaking rather than a quick dip. The park surrounding the bath sits within a special zone of the Jōshin'etsu-kōgen National Park, and the area is part of Kusatsu's broader hot spring walking district, which also includes the Yubatake source.

Access is simple: walk-ins are welcome and a day pass is available, with no requirement to be a hotel guest. The facility has gender-specific bathing hours, but on Friday evenings the men's outdoor bath becomes mixed bathing from 17:30 to 20:00 (with some exceptions on specific dates), and the bath is lit up during this time. Clothing is not optional in the regular baths.

The bath is open every day of the week from 7:00 to 20:00, with last entry at 19:30. Given the scenic surroundings and nearby walking paths, it works well as a stop combined with exploring the rest of Nishinokawara Park and the Yubatake area.