Iwama Onsen Yamazaki Ryokan

The indoor baths are split by gender, but the outdoor bath is a single shared one, mixed bathing, with a bathing wrap handed out at the changing room (blue for men, red for women). The water is clear, faintly salty, and smooth on the skin, fed straight from the spring with no dilution or recirculation, and you can drink it straight from the ladles set at the tap. Iwama Onsen is a one-inn hot spring at the end of a narrow mountain road in the Hakusan foothills, a member of the Nihon Hitou o Mamoru Kai (日本秘湯を守る会), the association for Japan's secluded hot-spring inns. By day you look out over Hakusan's green slopes; on clear nights guests mention seeing the Milky Way above the outdoor bath. An hour's walk from the ryokan, at the spring's own source high in the mountains, is a rougher open-air bath that hikers on Hakusan's Iwama trail often stop at.