Relaxing — deep, immediate muscle release.
Rich in active gases or metals — a strong mineral character.
Soft water — natural, classic buoyancy.
Naruko Onsen, at its Waseda Sajikiyu bathhouse in Ōsaki, Miyagi, heats sulfurous water to 68°C (pH 6.5). The venue offers an indoor bath, an outdoor rotenburo and a sauna.