Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
SoufreSulfuresSulfates
Aone Onsen Jappo no Yu, in Kawasaki, Miyagi Prefecture, draws sulfurous water at 43°C. An indoor bath, an outdoor rotenburo, and a sauna are offered in this mountainous setting of northern Japan.
Insider tip — Aone Onsen Jappo no Yu takes its playful name from a regional dialect word for the sound of splashing into water. Aone Onsen (青根温泉) is one of Miyagi most historic spa villages in the volcanic zone between the Zao massif and the Sendai hills, established by the Date clan as an aristocratic retreat in the early Edo period, and the sulfurous blue-green spring waters have been prized for skin therapy for over 400 years.