Takarabune Onsen Yumoto Kotobuki

Takarabune Onsen is a single-inn hot spring tucked into the wooded hills of Shimoogawa, Adogawa-cho, Takashima City, close to the Omi-Shirahama shore on the western side of Lake Biwa. Opened in 1967, the spring is managed entirely by Yumoto Kotobuki, a small ryokan with only four guest rooms, and its quiet setting has earned it a reputation as a hidden hot spring within easy reach of Kyoto.

The water is classified as a simple ferrous cold mineral spring of the bicarbonate type. The source emerges at 16.1 degrees Celsius with a neutral pH of 6.8 and a total mineral content of 0.19 g/kg, including 9.6 mg/kg of ferrous iron, 74.1 mg/kg of bicarbonate and 57.6 mg/kg of metasilicic acid. Clear at the spout, the water turns a cloudy reddish brown as the iron oxidises on contact with air, leaving flakes of brown mineral deposit drifting in the tub. It carries a distinctly metallic taste and aroma, while the metasilicic acid gives it a reputation as a skin-beautifying spring.

Bathing is split between indoor baths for men and women and a separate private open-air bath in its own outbuilding. The open-air tub, large enough for two and screened by trees, is heated and free-flowing, while the indoor bath uses filtration and recirculation. A barrel sauna and cold plunge have been added in recent years. Day-trip bathing costs 700 yen for adults and 350 yen for children from 9:00 to 20:00, and the private open-air bath starts at 3,000 yen for 50 minutes. The inn is closed on Mondays.