Many people come to Tamagawa Onsen for rest and for hot-spring therapy, as it differs from other onsens due to the unique high acidity of the water- a rarity world-wide.
When you stay here, you can bring your own food and custom-make your own meals. This, along with spending a long time at the onsen, makes for a great experience at this curative hot-spring.
In Jigokudani (Hell’s Valley), volcanic gases constantly billow out of the ground and make for quite a scene. This volcanism creates a natural stone sauna where visitors can lie on straw mats and warm their bodies with the heat from the earth.
AloJapan.com