酸ヶ湯（すかゆ）温泉：sukayu-onsen In Japan you wash & rinse outside the tub. Everyone uses the same tub water for soaking only. Onsens are places to enjoy hot springs bathing at inns, hotels & ryokans (Japanese traditional inns). Rotenburo are outside hot springs. Nature can be enjoyed while bathing in the rotenburo. Sentos are public bath houses found in residential neighboods. Ofuro is the bath in the home.