Outdoor bath called "Goenmonburo", a pot-shaped tub that in the old times was heated up from the bottom with fire, but now is just filled with onset water. Aoni Onsen, also known as Lamp no Yado, is a traditional Japanese ryokan located in the deep mountain of Aomori Prefecture. Rooms have no electricity and are lighted up with old oil lanterns. Its hot spring baths near the river are stunning.