Ryounkaku

Ryounkaku's baths draw on Matsunoyama Onsen's salty, pale green spring water, known locally as a medicinal bath that keeps you warm long after you get out. Two indoor baths swap between men and women through the day, and there's also a small family bath you can lock yourself into for a private soak, free of charge and without a reservation. The main building is a wooden three-story structure from 1938, registered as a national tangible cultural property, with the retro feel of early Showa architecture still intact. Each room in the old wing was finished by a different miyadaiku (宮大工), shrine carpenter, and the carpenters competed to outdo each other: ceilings shaped like open umbrellas or laid out as shogi and go boards, carved lattice windows, black gravel entryways, no two rooms alike. The bath is named Kagami-no-yu (鏡の湯, mirror bath) after a local legend about a pond where a grieving girl mistook her own reflection for her late mother. Ryounkaku belongs to Nihon Hitou wo Mamoru Kai (日本秘湯を守る会), a network of secluded hot-spring inns, and takes overnight guests only, with no day-use bathing.