Yudonburi Sakaeyu is a neighbourhood bathhouse near Minowa where every bath, tap and shower runs on natural hot-spring water, some of it warmed by rooftop solar collectors since 1979. The sento says the automatic heat-wave fan found in Japanese saunas began here, and a fine-bubble cold bath follows the sauna. Entry is ¥600 plus ¥600 for the sauna, and a trailer sauna can be booked separately. Open 14:00–23:00, from 12:00 on Sundays and holidays; closed Wednesdays.