Akayu Onsen Tansen Hotel

This ryokan in Akayu Onsen (赤湯温泉) runs two separate bathhouses, each pairing an indoor bath with its own outdoor rotenburo. One is styled like a Roman bath, round and lined in marble; the other is filled with the scent of hinoki cypress. The men's and women's sides swap between the two baths each morning, so a longer stay means trying both. Some of the guest rooms have their own onsen bath as well, and a separate private family bath, its tub made of hinoki, with grab bars and wheelchair access, can be booked on its own. The water is soft and gentle on the skin, mild enough that families here have long brought newborns for their first bath. Akayu Onsen has been a hot spring town for close to 930 years. Local legend ties its name, meaning red water, to warriors who bathed a battle wound here and tinted the spring red with blood. The hotel itself feels old and lived-in, and guests keep returning as much for the unhurried service and generous meals as for the baths.