Komo Onsen Unokoso

Unokoso is a single-inn hot spring standing beside the Saijo River in Komo-cho, Shobara City, deep in the Chugoku Mountains of Hiroshima Prefecture. The spring is said to have been found by a mining engineer during the Taisho era, and the inn opened for business in 1926. Because electricity had not yet reached this valley, it was known until around 1967 as a lamp inn, lit at night by kerosene lamps. The century-old wooden farmhouse is still in daily use, with the clear Saijo River curving past the front door and mountains rising on either side.

The water is classified as a simple weak radioactive cold mineral spring and is known locally as a radium spring, long valued as a toji (therapeutic bathing) water said to ease neuralgia and rheumatism. Because the source emerges below 25 degrees Celsius, it is heated before use. Published descriptions state that the bath is heated and circulated while source water is topped up automatically, and no primary source confirms a free-flowing kakenagashi supply. Figures for pH, source temperature and flow rate are not disclosed.

There is a single small indoor bath that fits four or five people, with a window looking down on the river. The inn takes only one or two groups per day and is strictly by reservation. Stays start at 11,000 yen per person with two meals. Bathing alone is not offered to day visitors: a day trip means a lunch-and-rest or dinner plan at 4,000 to 6,000 yen that includes the bath. Meals centre on river fish such as carp and ayu together with mountain vegetables, and parking is free for about ten cars.