Tokigasane

Tokigasane stands on the shore of Shibayama lagoon in Katayamazu Onsen, and several rooms look straight out over the water. The two large baths, Orihime (織姫) and Hikoboshi (彦星), swap between men's and women's hours on odd and even days; Hikoboshi's side also has a Finnish-style sauna next to its indoor and open-air pools. The salty spring water leaves your skin warm long after you get out and is said to help with poor circulation, though it's strong enough that soap won't lather well until you rinse off first. Some rooms have their own small open-air bath for one person plus a separate indoor tub. There's also a stone-bed bathing room, Hoshi no Fune (星の舟), where you lie on warmed stones instead of sweating in a sauna.