Yunohana Chaya Shinzaemon no Yu

Zao Onsen is said to have opened 1,900 years ago and is known as the oldest hot spring in Yamagata Prefecture. Its sulfur-rich water is among the most acidic in Japan and has strong antibacterial properties, which are believed to help relieve symptoms of cuts, burns, and atopic dermatitis. It is also said to promote circulation and improve the skin, earning it a long-standing reputation as a “beauty bath.”

In addition to a bath filled with 100% undiluted spring water, where you can experience its properties firsthand, there are also baths suitable for people with sensitive skin, including Shiroku no Yu and the Kame baths. Relax in the open-air baths surrounded by greenery or in the indoor bath.

The facility also has a restaurant and souvenir shop to visit after your bath. The restaurant serves signature Yamagata dishes, including juwari soba made with 100% domestically produced buckwheat flour and a sukiyaki set featuring Zao Beef, a local brand raised in Zao. The souvenir shop offers a wide selection of specialties from Yamagata Prefecture.

A sauna available exclusively by reservation opened in April 2023. It can be set as high as 248°F (120°C), and guests can choose from three aromas for self-service löyly, making it especially popular among sauna enthusiasts.