Komanoyu Onsen

Komanoyu Onsen sits at roughly 570 meters above sea level in the Kouei district on the southern flank of Mount Kurikoma, in Kurihara City, Miyagi Prefecture. The spring is said to have been opened in 1618 and served as a toji (therapeutic bathing) retreat for more than four centuries. In June 2008 the Iwate-Miyagi Nairiku Earthquake triggered a massive landslide directly above the inn, and the resulting debris flow destroyed the buildings. After seven years of closure, the site reopened in October 2015 as a day-use bathhouse paired with a soba cafe serving juwari (100 percent buckwheat) noodles.

The water is classified as a sulfur-bearing calcium sulfate spring of the hydrogen sulfide type. It emerges naturally at 36.4 degrees Celsius with a mildly acidic pH of 4.4 and a total mineral content of about 1,868 mg per kilogram, including 1,142 mg of sulfate and 405 mg of calcium. Free hydrogen sulfide at 7.0 mg gives the bath a clear sulfurous aroma. Nothing is added or altered: no dilution, no reheating, no recirculation and no chlorination, so faintly blue-tinged water pours continuously through the tub and over its rim.

Bathing is limited to a single small wooden indoor tub for each sex, about the size of four and a half tatami mats, comfortable for three to five people at a time. There are taps but no showers, no shampoo and no hair dryer; coin lockers cost 100 yen. Admission is 500 yen for adults, 300 yen for elementary school children and 100 yen for preschoolers aged three and over. Hours are 10:00 to 17:00, closed Wednesdays and the second and fourth Thursdays, with a full winter closure from mid-November to mid-April due to snow.