Sawatari Onsen Maruhon Ryokan

Maruhon Ryokan is a secluded inn set in the mountain hamlet of Sawatari Onsen in Nakanojo, Agatsuma District, Gunma Prefecture. Sawatari Onsen is said to have been opened in 1191, and legend holds that Minamoto no Yoritomo, after hunting at the foot of Mount Asama, soothed skin irritated by the fiercely acidic waters of nearby Kusatsu in this gentle spring. Ever since, it has been known as the "finishing bath of Kusatsu" and celebrated as a beauty spring nicknamed "one bath for flawless skin." Maruhon Ryokan has operated since the Edo period; after being lost in a great fire in 1945, it was rebuilt in 1948.

The water is a calcium-sodium sulfate-chloride spring with a source temperature of about 55 degrees Celsius and a mildly alkaline pH of 8.5. It is served entirely free-flowing from the source, with no added water, no heating, no recirculation and no disinfection. Colorless and transparent, it carries a faint hydrogen-sulfide scent and a remarkably smooth, skin-clinging texture.

The inn's pride is a mixed-gender main bath built entirely of hinoki cypress, from the tub to the floor and walls in the old bathhouse style; from 20:00 to 21:00 it becomes women-only. There is also a designer women's bath that won a 2016 JCD Design Award, and a family bath available for private use. Day-trip bathing is offered from 11:00 to 15:00 for 700 yen for adults and 500 yen for children.