Oyu Onsen Abe Ryokan

A small, secluded ryokan tucked into a river gorge in Akita's mountains, with separate indoor baths and an open-air rotenburo (露天風呂) overlooking the Minase River canyon. In summer (July to September), a seasonal riverbed bath opens directly in the river itself, one of the more unusual soaking experiences you'll find. The spring is pure sulfur, reportedly emerging at 98 degrees, and the water runs completely clear.