Photo by Panoramio upload bot, via Wikimedia Commons (CC BY-SA 3.0)
🇯🇵 Japan · Shirahone Onsen, Matsumoto, Nagano Prefecture, Chubu
Photo by Panoramio upload bot, via Wikimedia Commons (CC BY-SA 3.0)
🇯🇵 Japan · Shirahone Onsen, Matsumoto, Nagano Prefecture, Chubu
♨ Temperature
37°C
⛰ Altitude
—
⚗ pH
6.3
💧 TDS
—
🌊 Flow rate
—
📅 Established
1912
✓ Verified on 2026-07-28
Awanoyu is a hot spring ryokan in Shirahone Onsen, on the eastern flank of Mt. Norikura in Matsumoto, Nagano Prefecture. Shirahone Onsen's waters have reportedly flowed since the Kamakura period, and local tradition holds the springs were used by the warlord Takeda Shingen as a hidden bath for wounded soldiers during the Warring States period. Awanoyu itself was established in 1912. Its spring is a sulfur-bearing calcium-magnesium-bicarbonate type with a pH of 6.3; the water is colorless underground but turns milky white to cobalt blue on contact with air, as dissolved hydrogen sulfide and calcium form fine particles. It flows at around 37°C, a comparatively lukewarm temperature that is comfortable for long soaks, with an abundant discharge of about 1,730 liters per minute, one of the largest in Nagano Prefecture.
Shirahone Onsen's waters are said to have flowed since the Kamakura period, and local tradition holds that the 16th-century warlord Takeda Shingen used the springs as a hidden retreat for treating wounded soldiers and miners. Awanoyu, one of the area's ryokan, was established in 1912.
Bathers traditionally value Shirahone's water for the way its color shifts between milky white and cobalt blue depending on weather and season, a visible effect of hydrogen sulfide and calcium reacting with air — a distinctive feature that has become part of the area's identity.
Phone+81-263-93-2101
Websitewww.awanoyu-ryokan.com/awanoyu/english.html
Address4181 Azumi, Matsumoto, Nagano 390-1515, Japan