Hoteru Asahi Sō

A long, cave-like rock bath carved into the hillside is the centrepiece here, sodium-calcium bicarbonate water wells up from the floor through cracks in the stone, filling the air with steam. Separate rooftop rotenburo (露天風呂) for men and women sit above the valley. The inn has been running for nearly 70 years, and the interior keeps that comfortable retro feel.