Takaragawa Onsen

Takaragawa Onsen Osenkaku is a single mountain inn founded in 1923 in the Tanigawa range of Minakami, Gunma, spread along the banks of the Takaragawa river. It is renowned for hosting some of Japan's largest riverside open-air baths (rotenburo).

Hot spring water

The water is an alkaline, colorless spring with a soft feel on the skin and no sulfur smell. It emerges from the source at roughly 70°C and cools naturally to around 40–42°C in the pools. The baths are run in free-flowing kakenagashi style — water passes straight from the source through the baths without recycling, reheating, or chemical treatment — at a rate of over 1,800 liters per minute.

The four riverside rotenburo

• Kodakara-no-Yu (子宝の湘) — mixed bathing, roughly 200 tatami mats
• Maka-no-Yu (摩訴の湘) — mixed bathing, roughly 120 tatami mats
• Hannya-no-Yu (般若の湘) — mixed bathing, roughly 50 tatami mats
• Maya-no-Yu (摩耶の湘) — women-only, roughly 100 tatami mats

Ryokan & day-use bathing

The ryokan offers overnight accommodation with meals in a forest-and-river setting deep in the mountains.