Aso Akamizu Onsen

Aso Akamizu Onsen—Aso Red Waters Spring—takes its name from the distinctive red coloration of its ferruginous and acidic volcanic waters, whose combination of iron oxide and volcanic acid creates the characteristic reddish-brown staining that gives this Mt. Aso caldera spring its vivid descriptive name within one of Japan's most volcanically active and visually dramatic landscapes. The ferruginous and acidic mineral profile represents one of the most assertively volcanic spring compositions in Japanese balneology—the iron richness providing blood-building and circulatory mineral benefits while the acidic volcanic component delivers the sharp, pore-cleansing astringency that makes acidic springs particularly invigorating for the skin. Rising within the Aso caldera's exceptional geothermal landscape, Akamizu's red volcanic waters offer the most dramatically named and visually distinctive thermal spring experience of this world-famous volcanic caldera region.