Cave Onsen of Shinmeikan

Kurokawa Onsen is known for its rotemburo (outdoor baths) but if you're ready for something a little bit different, try out the cave onsen of Ryokan Shinmeikan. Passageways carved out of the rock reach back far into the hill; the water in some spots can be as deep as one's waist. The steamy air makes for poor visibilty so caution is needed when moving around the onsen but this is an incredibly unique experience. There are three separate bathing areas, one for women only and two that are mixed gender.