Zao Onsen Oomiya Ryokan

Zao Onsen, spread across a highland plateau at about 880 meters elevation in Yamagata City, is one of Tohoku's most celebrated hot springs, said to have been discovered around 110 AD by Kibi no Takayu, a retainer of Prince Yamato Takeru, giving it roughly 1,900 years of history. Oomiya Ryokan stands at the heart of this hot spring town, a long-established inn reputedly founded over 1,000 years ago, charming visitors with fully tatami-matted floors and a nostalgic Taisho-era ambiance adorned with woodblock prints by Yumeji Takehisa.

The water is an acidic sulfur-containing aluminum sulfate-chloride spring with a pH of 1.9, ranking among the most strongly acidic springs in Japan. Flowing naturally from the Oumiya No. 2 source at 53.3 degrees Celsius, the milky-white water carries the scent of sulfur and is served as 100% free-flowing spring water without heating or dilution. Known for strong antibacterial and warming properties, it is said to benefit cuts, burns, and chronic skin conditions.

Bathing facilities include the wooden Tamago Onsen, a source bath and bubble bath, an open-air source bath, and a footbath. Day-trip bathing is available from 12:00 to 14:00 for 880 yen per adult. The open-air bath is closed in winter from late November to early April. Overnight stays include two meals, and free shuttle service from Yamagata Station is available.