Zao Onsen — Sulfur Springs and Ski Resort Village

Zao Onsen is a high-altitude hot spring village at 880 meters elevation on the slopes of Mt. Zao, one of Japan's oldest onsen resorts with 1,900 years of recorded history. The spring water is strongly acidic sulfuric (pH 1.5-2.0), emerald-green in color, and known for skin-beautifying properties — the acidity exfoliates dead skin cells while sulfur minerals nourish. The village has three large public bathhouses and numerous outdoor foot baths scattered along the main street. In winter, Zao Onsen transforms into a ski resort, with lifts accessing the juhyo (snow monsters) zone and ski runs directly from onsen hotels. The combination of challenging skiing and powerful hot springs makes Zao unique among Japanese ski destinations. The village retains traditional character despite tourism — steep stone pathways, wooden onsen buildings with steam rising from windows, and sulfur smell permeating the mountain air.