Rich in active gases or metals — a strong mineral character.
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
SoufreSulfuresSulfates
Ashitsuke Onsen sits on Shikinejima Island, part of the Tokyo archipelago. Its sulfurous water (pH 6.5) feeds an indoor bath, an oceanview rotenburo and a sauna.
Insider tip — Ashitsuke Onsen (足付温泉, the 'footbath' onsen) is on Shikinejima Island (Izu Islands, Tokyo), very close to Jinata Onsen. It is a rocky seaside onsen with free access — a natural pool fed by highly acidic volcanic springs surrounded by lava. Shikinejima Island is reachable by ferry from Shimoda or by plane from Tokyo.