One of Japan’s Most Sulfur-Rich Hot Springs
The defining feature of Manza Onsen is its distinctive hot spring water. The springs are generally classified as acidic sulfur springs containing hydrogen sulfide, and the water is often milky white or yellowish in color.
The sulfur content is said to be among the highest in Japan. The source temperatures are around 80°C, while the total volume of naturally emerging hot spring water reaches approximately 5.4 million liters per day, or around 3,750 liters per minute.
For centuries, people have visited Manza for hot spring bathing and therapeutic bathing traditions. Today, visitors come primarily to enjoy the distinctive mineral water, mountain scenery, and relaxing atmosphere.
Manza Onsen was selected as the national No. 1 destination in the “Hidden and Famous Hot Springs” category of the 2024 and 2025 Onsen Election, reflecting its continued popularity among hot spring enthusiasts in Japan.
A Distinctive Milky Sulfur Spring
The sulfur-rich water has a strong mineral character and a distinctive aroma. The appearance can vary from milky white to yellowish depending on the spring source and conditions.
Because acidic sulfur springs can be relatively stimulating to the skin, visitors should follow the bathing instructions provided by each facility and avoid staying in the water for excessively long periods.
27 Different Hot Spring Sources
One of the pleasures of visiting Manza Onsen is discovering the variety of its spring sources. The resort has approximately 27 different sources, including Uba-yu, also known as the Yubatake or “hot spring field,” Daiku-yu, Tetsu-yu, Hossho-no-yu, and Radium Hokko-sen.
Individual accommodations use different sources, while some combine water from several sources. As a result, the color, aroma, temperature, and mineral character of the baths can differ from one facility to another.
Hot Spring Hopping with a Yumeguri Pass
Visitors can use the Manza Onsen Yumeguri Pass to enjoy bathing at multiple facilities. This makes it possible to compare the different characteristics of Manza’s hot springs while exploring the resort.
Many baths also offer outdoor bathing areas where guests can enjoy panoramic mountain views. During the day, the baths may be surrounded by blue skies and mountain scenery, while at night, the same outdoor baths can become peaceful places for viewing the stars.
Manza Onsen Ski Resort and Four Seasons of Nature
Behind the hot spring village lies Manza Onsen Ski Resort, a popular winter destination known for its light, dry powder snow.
In addition to skiing and snowboarding, visitors can enjoy activities such as snowshoeing and snow tubing. The resort is also known as one of the filming locations associated with the Japanese ski movie Take Me Skiing.
Spring and Summer
Spring brings melting snow and fresh green vegetation to the mountains. As the season progresses, alpine plants and wildflowers begin to appear.
Because of its high elevation, Manza remains considerably cooler than many lowland areas during summer. The crisp mountain air makes it a popular summer retreat for travelers seeking relief from the heat.
Autumn Foliage
Autumn arrives early in the highlands around Manza. From around late September to early October, the surrounding mountains become covered in brilliant red, orange, and golden foliage.
Viewpoints such as Manzanbo and the Kumashiroyama Observatory offer impressive views of the colorful mountains and the surrounding highlands.
Winter Snow Scenery
In winter, Manza is transformed into a snowy mountain resort. The white landscape, rising steam, and milky sulfurous water create an especially atmospheric scene.
Snowshoe walks and other winter activities provide another way to experience the quiet mountain environment, while outdoor baths surrounded by snow offer one of the area’s most memorable seasonal experiences.
Walking Among Volcanoes and Alpine Nature
The area around Manza Onsen is filled with landscapes shaped by volcanic activity. One of the most distinctive sights is Karabuki, where water heated underground emerges as steam together with hydrogen sulfide gas.
The barren ground around the steaming area contrasts sharply with the surrounding forests and alpine vegetation, providing a vivid reminder that Manza lies within an active volcanic region.
Karabuki – A Glimpse of Volcanic Activity
Karabuki is one of the signature natural sights of Manza Onsen. Steam rises from the former volcanic crater area, creating a striking landscape where very little vegetation grows.
Although the amount of escaping steam has decreased compared with the past, the sight remains an impressive reminder of the geological forces beneath the mountains.
Because hydrogen sulfide gas can be hazardous, visitors should remain on designated paths and behind safety barriers and follow local safety instructions.
Ushiike Pond and Ushiike Marsh
Ushiike Pond is a clear mountain pond approximately two meters deep. Depending on the light and weather conditions, its surface can appear emerald green.
A walking path surrounds the pond, making it an accessible place for a short nature walk. Nearby Ushiike Marsh is home to alpine and wetland plants, including Veratrum and sundews, while the early summer landscape is decorated with delicate wildflowers.
Kumashiroyama – A Mountain Viewpoint
A walking trail with an elevation gain of approximately 100 meters leads to an observation point on Mount Kumashiro.
From the viewpoint, visitors can look down over Manza Onsen and the surrounding mountains. The area is pleasant for a short hike in summer, while autumn foliage and winter snow create completely different landscapes.
Kumashiro Rock Cave – History and Local Legend
Earthenware dating from the Yayoi period was discovered around Kumashiro Rock Cave, providing evidence of human activity in the area in ancient times.
The site is also associated with a local legend in which two loyal dogs named Kuma and Shiro saved a hunter from a giant serpent. Such stories add a layer of cultural history to the area’s natural scenery.
Yakushido Temple – A Place Connected with Hot Spring Culture
Yakushido was built in 1715 and enshrines Yakushi Nyorai, the Buddha traditionally associated with healing and medicine.
The small temple is closely connected with the history of Manza as a hot spring destination. Visitors can stop here during a walk and experience a quiet moment of traditional Japanese religious culture amid the mountain landscape.
Nature Around Manza Onsen
Manza Onsen Ski Resort Viewpoints
Although the area is especially lively in winter, the surroundings of Manza Onsen Ski Resort are also attractive during the green season.
From the high slopes, visitors can enjoy broad views of the surrounding mountains. Under favorable weather conditions, clouds may form below the viewpoints, creating a spectacular sea of clouds. Early morning and evening can be particularly beautiful as the changing light silhouettes the mountains.
Kenashitoge Pass
Kenashitoge Pass, located at the end of a prefectural road, offers dramatic views of Mount Happu and, on clear days, distant mountains including the Northern Alps.
The area was once associated with the Ogushi Mine, where sulfur was extracted. Remains of the former mining operation provide an interesting connection between the region’s natural environment and industrial history.
Yoshigadaira Wetland Group
The Yoshigadaira Wetland Group was designated as a Ramsar Wetland of International Importance in 2015. The area contains wetlands and ponds formed through volcanic activity and is recognized as an important alpine wetland environment.
Walking and trekking routes allow visitors to experience the broad wetland landscape and observe plants such as cottongrass and other alpine species.
A Long History of Hot Spring Culture
The exact date when Manza Onsen was first discovered is unknown. However, the discovery of Yayoi-period pottery in the surrounding area suggests that people have been present in this mountain region since ancient times.
Local traditions include legends associated with Sakanoue no Tamuramaro, a celebrated military figure of the early Heian period. Historical accounts also suggest that warriors visited the hot springs for bathing during the Warring States period.
During the Edo period, Manza developed as a destination for toji, the traditional Japanese practice of staying at a hot spring resort for an extended period while enjoying repeated bathing and a slower lifestyle.
Development as a Mountain Resort
Manza underwent major development after World War II, when transportation improvements and resort development associated with the Seibu Group made the high-altitude destination more accessible.
Today, some accommodations continue to offer long-stay and self-catering options, allowing visitors to experience a modern version of the traditional hot spring retreat.
A Quiet Hot Spring Village in the Mountains
Unlike large urban-style hot spring resorts with extensive entertainment districts, Manza Onsen has a quiet, nature-oriented atmosphere.
Hotels and traditional inns are scattered along the mountain slopes, with steam rising from the sulfurous hot springs. The combination of mountain scenery, sulfur aromas, and quiet surroundings creates an atmosphere that feels remote despite the area’s accessibility.
Because Manza is located within Joshin’etsukogen National Park, development is subject to landscape and environmental regulations. As a result, the resort retains a relatively natural appearance and avoids the large-scale urban atmosphere found in some other hot spring towns.
A Place to Escape the City
There are no large commercial districts or convenience stores within the hot spring area. Accommodation facilities generally provide shops where guests can purchase necessities and souvenirs.
Visitors can find products made with Tsumagoi highland cabbage, sweets made with locally grown flower beans, and sake from Gunma Prefecture.
The absence of large entertainment facilities is part of Manza’s appeal. Instead, the experience centers on hot springs, mountains, fresh air, quiet walks, and the night sky.
Bathing Facilities for Different Travel Styles
Manza Onsen currently has approximately seven inns and hotels serving individual travelers. These facilities range from traditional hot spring inns to larger resort hotels, and each offers its own combination of spring sources and bathing facilities.
Manza Prince Hotel
Manza Prince Hotel features spacious indoor and outdoor bathing facilities, including Komakusa-no-yu and the women’s-only Shakunage-no-yu outdoor bath.
The baths use milky water from the Uba-yu, or Yubatake, source. The hotel also has a mixed-gender outdoor bath where guests can enjoy the surrounding natural scenery.
Manza Kogen Hotel
The hotel’s signature Ishitei Outdoor Baths consist of eight different pools, making the facility one of the best-known bathing experiences in Manza.
Several hot spring sources are used, allowing visitors to experience differences in water color and mineral characteristics within the same bathing complex.
Manza Onsen Nisshinkan
Manza Onsen Nisshinkan offers several indoor baths using sources such as Nigori-yu, Uba-yu, and Tetsu-yu.
Because multiple baths are available within the same property, guests can enjoy a form of hot spring hopping without leaving the accommodation. The inn also offers programs connected with health and traditional hot spring culture.
Manza Hotel Juraku
Manza Hotel Juraku has an outdoor bath supplied by the Hossho-no-yu source. From the bath, guests can see the volcanic landscape of Karabuki.
The hotel also offers an all-inclusive style of stay and workshops, providing an alternative way to enjoy a mountain retreat.
Manzatei, Hokkoku-kan, and Yunohana Ryokan
Manzatei, Hokkoku-kan, and Yunohana Ryokan retain elements of the traditional hot spring inn atmosphere.
Wooden bathing areas and simple baths create a more traditional experience, while some facilities offer self-catering plans for longer stays. These accommodations are suitable for travelers interested in experiencing the quieter side of Japan’s traditional toji culture.
Day-Use Bathing and Hot Spring Hopping
Several accommodations in Manza accept day visitors, allowing travelers who are not staying overnight to experience the famous sulfur springs.
This can be particularly convenient for people traveling through the area by car or returning from a mountain hike.
Opening hours and admission fees vary by facility, so visitors should check the latest information before arriving. Visiting outside peak periods can also provide a quieter bathing experience.
Comparing Different Spring Waters
The Yumeguri Pass provides an opportunity to visit multiple bathing facilities and compare their different waters. Depending on the source, visitors may encounter milky water, iron-rich water, or springs with different mineral characteristics.
Experiencing these subtle differences is one of the distinctive pleasures of visiting Manza Onsen.
Traditional Toji Culture and Longer Stays
Manza has a long history as a toji destination. Traditionally, people would stay at hot spring resorts for several days or longer, combining regular bathing with rest and a simple lifestyle.
Some accommodations in Manza continue to offer self-catering facilities and long-stay plans, making it possible to experience a contemporary version of this tradition.
The highland environment, cool air, quiet surroundings, and opportunities for walking make Manza suitable for travelers seeking a slower-paced retreat.
Bathing Safely
Because acidic sulfur springs can be relatively strong, visitors should avoid excessively long baths and take regular breaks. Drinking water and staying hydrated is also important, particularly after outdoor activities.
Anyone with concerns about bathing in mineral-rich hot springs should follow the guidance provided by the bathing facility and consult a medical professional when appropriate.
Local Cuisine and the Flavors of Tsumagoi
Manza Onsen is located in Tsumagoi Village, one of Japan’s leading areas for summer and autumn cabbage production.
Tsumagoi Highland Cabbage is known for its crisp texture and sweetness, which develop under the area’s distinctive highland climate and large differences between daytime and nighttime temperatures.
Accommodation facilities also serve dishes using regional ingredients such as Joshu beef, Ginhikari trout, and flower beans.
Farm-to-Table Flavors from Gunma
Regional dishes may include Joshu beef sukiyaki, grilled beef dishes, Gunma’s branded Ginhikari trout, and desserts made with flower beans.
Enjoying seasonal local ingredients after a day of sightseeing and hot spring bathing adds another dimension to a stay in Manza.
Surrounded by the Mountains of Joshin’etsukogen National Park
At approximately 1,800 meters above sea level, Manza Onsen is surrounded by the mountainous landscape of Joshin’etsukogen National Park.
Mountains reaching around 2,000 meters rise around the resort, while volcanic activity has created distinctive landforms, exposed rock slopes, steaming areas, and other dramatic geological features.
Manza is located near volcanic areas including Mount Asama and Mount Kusatsu-Shirane. This gives the landscape a striking contrast between rugged volcanic terrain and forests and alpine vegetation.
Four Seasons in the Manza Highlands
Spring and Summer: Fresh Greenery and Alpine Flowers
As the snow melts in spring, fresh green vegetation appears across the mountain slopes. Alpine plants and delicate wildflowers begin to bloom, creating excellent opportunities for nature walks.
Summer is pleasantly cool compared with the lowlands. Although sunlight can be strong at high elevation, the mountain air is generally crisp and refreshing, making the area a popular summer escape.
Autumn: A Mountain Landscape of Red and Gold
Autumn transforms the surrounding mountains into a spectacular display of red, orange, and yellow.
The foliage is particularly beautiful from around early to mid-October. On clear days, the dry mountain air can provide remarkably sharp views across the surrounding peaks.
Winter: Snow, Steam, and Silence
Winter covers Manza in a vast landscape of snow. Steam rising from the hot springs creates an atmospheric contrast against the white mountains and forests.
A snow-viewing outdoor bath is one of the most memorable ways to experience the season, while snowshoeing allows visitors to explore the quieter winter landscape on foot.
Stargazing Above the Clouds
Manza’s high elevation and limited artificial lighting make it an excellent place for stargazing.
On clear nights, countless stars can be seen overhead, and under favorable conditions the Milky Way may be visible to the naked eye.
Some accommodations organize guided stargazing events, allowing visitors to learn about the night sky while enjoying the exceptionally dark mountain environment.
Watching the stars from an outdoor hot spring bath is one of the most memorable experiences Manza can offer.
Winter Hiking and Snow Activities
During winter, Manza becomes a world of snow. The area’s dry powder snow is ideal for skiing and snowboarding, while snowshoeing offers a quieter way to explore the forests and snowy fields.
Walking through the snow and looking for animal tracks can also provide an enjoyable glimpse into the winter ecology of the mountains.
Temperatures can fall well below freezing, so visitors should bring suitable winter clothing, footwear, and other equipment for severe mountain conditions.
Access to Manza Onsen
By train, the nearest station is Manza-Kazawaguchi Station on the JR Agatsuma Line. From there, buses take approximately 40 minutes to reach Manza Onsen.
From Karuizawa Station, which is served by the Hokuriku Shinkansen, the journey by bus takes approximately 90 minutes.
By car, the Manza Highway provides access to the resort throughout the year. During winter, however, heavy snow and icy roads are common, so vehicles should be equipped with winter tires and, when necessary, snow chains.
Check Mountain Road Conditions Before Traveling
The Shiga-Kusatsu-Kogen Route can be subject to seasonal winter closures and temporary traffic restrictions related to volcanic activity.
Because mountain conditions can change rapidly, visitors should check the latest road and transportation information before setting out, particularly when traveling in winter or during periods of volcanic activity.
A Hot Spring Retreat Above the Clouds
Manza Onsen is a unique combination of high-altitude hot springs, volcanic landscapes, alpine nature, and traditional Japanese bathing culture.
The milky sulfur-rich water, mountain views, clear highland air, seasonal scenery, and dark night skies create an atmosphere very different from the cities of Japan.
From soaking in an outdoor bath surrounded by snow to walking through autumn-colored mountains, exploring volcanic landscapes, or looking up at the Milky Way on a clear night, Manza offers many ways to experience the natural character of the Japanese highlands.
Experience the Quiet Side of Japan’s Hot Spring Culture
For travelers seeking a peaceful mountain retreat, Manza Onsen offers an opportunity to slow down and experience a traditional hot spring destination surrounded by nature.
A stay in this high-altitude “hot spring village above the clouds” is a chance to enjoy Japan’s volcanic landscape, seasonal mountain scenery, and the enduring culture of hot spring bathing in one unforgettable destination.