Akakura Onsen Yumori-no-yado Sannojo

The centerpiece here is a large, ancient rock bath (rotenburo, 露天風呂) where the water rises directly from the riverbed beneath the stones, a rare ashimoto-yushutshu setup. Three pools share the space, all fed by clear, mildly sulfurous water flowing straight from the source without circulation. The bath itself feels like it has been there forever, which it essentially has.