Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
SoufreSulfuresSulfates
Tomo no Hana Onsen Hoyo Center, in Toshima Village, Japan, draws sulfurous water with a pH of 6.5. The facility offers an indoor bath, an outdoor rotenburo and a sauna.
Insider tip — Tomo no Hana Onsen Hoyo Center is a balneotherapy center on one of the Tokara Islands (十島村, Kagoshima), a remote volcanic archipelago between Kyushu and Amami-Oshima. The Tokara Islands (12 islands, ~700 inhabitants) are among the most isolated places in Japan — no convenience store, no resident doctor. The Toshima ferry runs only 3 times a week.