Zao Onsen Sunoko-no-yu Kawaraya

A small day-use bathhouse in Zao Onsen with one small indoor tub each for men and women, built right over its own spring: the tub floor is slatted wood, and the hot water wells up straight through it, reaching bathers before it has touched the air. The spring is a strong sulfur water, acidic enough that the changing room skips lockers and keeps valuables at the front desk instead. Families from around Yamagata come in summer for heat rash, and locals say the bath is not too hot, so even children can soak easily. Past the bath there is a small soba and drinks counter, a souvenir corner, and two paid resting rooms for those who want to stay longer.