Shiobara Onsen
The town of Shiobara Onsen is located between Mt. Nasu (1,915 m) and Mt. Takahara (1,795 m) in a valley that was carved out by the Hoki River. Eleven separate communities have developed around the clusters of hot springs (onsen) that bubble up along the river and dot the landscape. Suspension bridges link the two sides of town, framing the natural beauty of the valley.
Each of the 11 onsen areas contains many individual hot springs, all with different colors, mineral compositions, and pH values. Their waters are gray, black, gold, milky white, reddish brown, pale green, or colorless (clear). The mineral compositions of the Shiobara springs can be divided into six major classifications: chloride springs, hydrogen carbonate springs, sulfur springs, sulfate springs, acid springs, and “simple springs.” The last type—simple springs—refers to any spring whose mineral content ratio does not exceed one part per thousand. The springs are also categorized by their pH values as acidic, neutral, or weak alkaline.