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Nikko NP, Tochigi
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In 1878, traveler Isabella Bird saw people with rheumatism lie for hours on planks above Yunodaira’s steaming spring to inhale its sulfur vapors—a vivid record of old-time hot-spring therapy.
Fresh water at the source can look vivid emerald green, then turn milky white when it meets the air. The color change comes from oxidation of Yumoto’s sulfur-rich spring water.
A 2024 Environment Ministry plan records 19 Yunodaira springs, most flowing naturally at 52–80°C. Together they yield 1,769.5 L per minute, supplying Yumoto and communities as far away as Kotoku and Chuzenji.
When Isabella Bird visited in June 1878, she found all 4 bathing sheds crowded and noted that some determined bathers went in as many as 12 times a day.
Yumoto’s hot water has supplied Chuzenji Onsen since 1951, traveling about 12 km through pipes. It cools on the way from its near-boiling source to bathing temperature.
A miniature bronze shrine found at nearby Onsen Shrine is engraved with the year 1513. Japan’s Tourism Agency says the find suggests Yumoto’s hot springs were already in use then.
Neighboring Onsenji Temple was crushed by a huge boulder during a 1966 typhoon. Its Yakushi Buddha statue survived and was found perched on the rock; the temple was rebuilt in 1973.
Temple tradition credits monk Shodo with discovering the springs in 788. He named the place Yakushi-yu, or the healing waters of Yakushi, and enshrined Yakushi Nyorai, the Buddha of Healing.
In the old seasonal spa, 9 licensed hot-spring keepers ran Yumoto’s bathhouses for just 5 summer months. Visitors paid bathing fees to the nearby Chuzenji Betsusho.
Hot springs also seep into nearby Lake Yunoko’s northeast corner, where Nikko City notes that waterbirds visit in winter—a quiet wildlife ripple of the same geothermal landscape.
In 1954, Nikko Yumoto joined Sukayu and Shima as one of Japan’s first designated National Health Hot Spring Resort Areas—the program’s inaugural group.
