Zao Onsen Robata

This tiny inn in Zao Onsen has its own natural spring rising right on the property, feeding the bath with nothing added. The single private bath, Yu no Ka (湯の香), is a cypress-built room for up to four, and since the free-flowing water barely oxidises, it comes out of the spout almost clear. Out front there's also a free, roofed footbath, Kutsurogi no Yu (寛ぎの湯), fed by the same spring and open to anyone passing through. The inn itself is small, just three rooms, more of a hideaway than a hotel, and the private bath comes free for anyone staying the night. Downstairs is a Jingisukan restaurant serving the grilled lamb dish said to have started here in Zao Onsen, along with mountain vegetables and other local food; it's open to walk-in diners too, not just guests.