Kawayu Onsen 川湯温泉
The steaming waters of the Oto River in winter
The river bath
In this mountain resort and spa, you can bathe (yu - hot water in Japanese) in the river (kawa) itself, soaking in the hot water while losing yourself in the picturesque pine hills...
Because here, you can bathe in the Oto River itself, whose cold waters mixed with boiling water from an underground spring, creating a natural onsen. Locals, tourists and pilgrims walking the Kumano trail alike come here and dig a small space in the gravel of the river bed, and then settle in for an unforgettable experience, soaking in the waters while surrounded by the pine forests that cover the surrounding mountains.
Made famous by the pilgrimage routes of Kumano, today Kawayu is a popular and upscale resort (many luxury ryokan hotels line the riverside).
In the winter (December - February), a huge bath called sennin buro ("bath for 1000 people"), is brought in for people to bathe free of charge.