Kumanoyu Onsen is a secluded hot spring resort in Shiga Kogen, Yamanouchi Town, northern Nagano Prefecture. Surrounded by magnificent mountains and rich natural scenery, it is known for its striking emerald-green hot spring water and the traditional legend behind its name.
At a high elevation, Kumanoyu offers a cool mountain climate and beautiful scenery that changes with the seasons. It is an ideal place to relax in a historic hot spring while enjoying the peaceful atmosphere of the mountains.
Kumanoyu Onsen is located in the Shiga Kogen area of Yamanouchi Town, where high mountains, forests, wetlands, and volcanic landscapes create a distinctive natural environment.
The area was once regarded as part of Heion Onsen, an older name associated with what is now the Yudanaka-Shibu Onsen area. Today, Kumanoyu is appreciated as a quiet mountain hot spring where history and nature exist side by side.
The name Kumanoyu literally means “Bear’s Hot Spring.” According to local legend, an injured bear once came to these waters and soaked in the hot spring to heal its wounds.
The story has become an enduring symbol of the healing power traditionally associated with the spring. Even today, the legend remains an important part of the identity of Kumanoyu and adds a sense of mystery to this remote mountain hot spring.
The hot spring water at Kumanoyu is classified as a sulfur-containing calcium-sodium bicarbonate and sulfate spring. The source temperature is approximately 63°C.
Its most distinctive feature is the exceptionally strong sulfur content and its beautiful emerald-green color. The color is created by the spring’s mineral components and the way they reflect sunlight, producing an especially vivid appearance.
The combination of the sulfur-rich water, mountain setting, and striking color makes bathing at Kumanoyu a memorable part of a visit to Shiga Kogen.
Because the water is rich in sulfur, it has traditionally been valued for bathing and hot spring therapy. It has been associated with relief for conditions such as rheumatism, skin disorders, cuts, and neuralgia.
Visitors interested in Japan’s traditional hot spring culture can experience not only a scenic bath but also the long-standing practice of using mineral-rich thermal waters for relaxation and wellness.
Unlike larger Japanese hot spring towns, Kumanoyu does not have a commercial streetscape lined with numerous shops and inns. Instead, the area has a remarkably quiet atmosphere, with Kumanoyu Hotel serving as the central accommodation and bathing facility.
This secluded setting is one of the area’s greatest attractions. Away from the bustle of urban life, visitors can spend peaceful time surrounded by forests and mountains.
Kumanoyu Hotel owns the Kumanoyu hot spring source and has welcomed visitors for many years. Its indoor and outdoor baths offer views of the surrounding mountains, allowing guests to experience the landscape while soaking in the spring.
The scenery changes dramatically throughout the year. Fresh green foliage appears in spring, colorful leaves cover the mountains in autumn, and deep snow creates a quiet winter landscape. The same hot spring therefore offers a different atmosphere with every season.
The history of Kumanoyu Onsen reaches back to the Edo period, when the area was already known for its thermal waters.
In 1848, the scholar Sakuma Shozan is said to have discovered the hot spring in this area and reported its qualities to the Matsushiro Domain. He described the water as being similar to that of Kusatsu Onsen, one of Japan’s most famous hot spring resorts.
In 1882, Yamamoto Yasokichi established accommodation and bathing facilities, making the hot spring available to a wider range of visitors.
These milestones reflect the long history of Kumanoyu as a place where people have traveled into the mountains to enjoy and make use of its distinctive thermal waters.
Another hot spring known as Suzurikawa Onsen is located nearby, across the Kakuma River from its confluence. Because of their proximity, the two areas were sometimes confused in the past.
At the end of 2000, Suzurikawa Onsen was renamed Hotaru Onsen, meaning “Firefly Hot Spring.” The area is notable for the unusual opportunity to observe fireflies at high elevation, adding another natural attraction to the mountains of Shiga Kogen.
Kumanoyu is part of Shiga Kogen, an extensive highland region within Joshin’etsukogen National Park. The highlands generally lie above 1,000 meters and offer a cool climate and rich natural environment.
Even in summer, temperatures rarely rise above 30°C, making Shiga Kogen a popular place to escape the heat. Forests, wetlands, ponds, mountain peaks, and alpine landscapes provide opportunities for hiking and nature exploration during the warmer months.
From autumn into winter, the scenery changes with elevation. Brilliant autumn foliage gradually gives way to snow-covered mountains, with the first snowfall generally observed from mid to late October.
By November, winter is well established, and visitors arrive for skiing and snowboarding. The contrast between the steaming hot spring and the surrounding snowy landscape is one of the special pleasures of visiting Kumanoyu during the cold season.
Shiga Kogen experiences a climate influenced by the Sea of Japan, while its inland location contributes to relatively stable snowfall. The average maximum snow depth is around 2.5 meters, although much greater amounts can occur at higher elevations.
At Shibu Pass, which rises above 2,100 meters, annual snowfall can exceed 4 meters. Winter temperatures can also fall below -20°C, creating a spectacular landscape of deep snow, frozen forests, and clear mountain air.
For visitors accustomed to warmer climates, the combination of a steaming hot spring and a dramatic snow-covered mountain environment offers a particularly memorable Japanese winter experience.
From JR Nagano Station, take a Nagaden bus on the Express Shiga Kogen Line. The journey takes approximately 1 hour 40 minutes. Get off at the Kumanoyu bus stop.
From Nagano Dentetsu Yudanaka Station, take a Nagaden bus on the Shirane Volcano Line or a service requiring a transfer at Hasuike Terminal. The journey takes approximately 40 minutes to the Kumanoyu bus stop.
From the Shinshu-Nakano Interchange on the Joshin’etsu Expressway, the drive is approximately 30 kilometers via National Route 292.
The mountain road itself offers changing views throughout the seasons, making the journey part of the experience. In winter, however, heavy snow and mountain road conditions require appropriate preparation.
Kumanoyu Onsen combines a historic hot spring, striking emerald-green water, and the magnificent natural environment of Shiga Kogen. Its secluded atmosphere makes it especially appealing to travelers looking to escape the noise of cities and spend quiet time in the mountains.
Whether visiting amid fresh spring greenery, colorful autumn foliage, or deep winter snow, the experience of soaking in the sulfur-rich waters while surrounded by the mountains is distinctly Japanese.
As a destination for experiencing both the hot spring culture and natural beauty of Shiga Kogen, Kumanoyu Onsen offers a peaceful retreat where history, legend, thermal waters, and mountain scenery come together.