Shika no Yu Onsen (Hokkaido)

Shika no Yu Onsen in Shintoku Town, Hokkaido—the Deer Hot Waters—is a wild natural spring (noyu) on the bank of the Yuyanbesu River in the Shizarikyo valley, where deer were observed bathing in the volcanic thermal water—following the ancient Japanese spring discovery legend that credits wild animals with leading humans to volcanic waters through their instinct. This outdoor wild spring is part of the Shizarikyo Onsen designation as a national health resort, situated within the volcanic highland between Lake Shikotsu and the Daisetsuzan National Park where Hokkaido's most active volcanic geology drives exceptional thermal spring emergence. Simple alkaline waters in a riverside wild-spring setting within one of Hokkaido's most pristine volcanic landscapes offer the most authentic frontier thermal bathing experience—the spring as nature originally formed it, without architectural intervention.