Iwate Yumoto Onsen

Iwate Yumoto Onsen—Iwate Origin Spring—is a bicarbonate and carbonated thermal spring in Iwate Prefecture, the largest prefecture on Honshu by area and a landscape of extraordinary geological, cultural, and scenic diversity where the Ou Mountain Range's volcanic activity produces springs of considerable mineral richness across the prefecture's broad highland interior. The effervescent, skin-stimulating quality of naturally carbonated bicarbonate waters provides a lively mineral soak that mirrors the dynamic geological character of Iwate's volcanic landscape, where the same geological forces that created the Matsukawa and Appi highlands also generate the CO2-rich mineral waters of this origin spring. The yumoto designation—origin or source spring—marks Iwate Yumoto as a primary thermal source within its local spring landscape, a spring whose waters represent the pure geological output at the emergence point.