Manza Onsen, Gunma Prefecture Complete Guide｜Thorough Explanation of Heaven’s Secret Hot Spring at Elevation 1800m
What is Manza Onsen? Japan’s Highest Altitude Hot Spring Resort Boasted by Gunma Prefecture
Manza Onsen (万座温泉) is a hot spring resort located at an elevation of approximately 1,800 meters in Hoshimata, Tsumagoi Village, Agatsuma County, Gunma Prefecture. Located within Joshin’etsu Kogen National Park, it springs from the southwestern foot of Kusatsu-Shirane Mountain. As a year-round hot spring accessible by private vehicle, it ranks alongside Nigorigawa Onsen in Gifu Prefecture as Japan’s highest altitude hot spring resort.
This secret hot spring, also called the “Heaven’s Hot Spring Resort,” was selected as the national #1 in the “Secret and Famous Hot Springs” category of the Hot Spring Grand Prix for two consecutive years in 2024 and 2025, with its spring quality and atmosphere highly evaluated. Since the late Edo period, it has prospered as a therapeutic hot spring destination and continues to captivate many hot spring enthusiasts and tourists today.
History and Origins of Manza Onsen
The history of Manza Onsen is ancient, with visitors already crowding the therapeutic hot spring in the late Edo period. While there are various theories about the origin of the name “Manza,” one theory suggests it means “a hot spring resort so vast that it can seat ten thousand people.”
Since the Meiji era, it has been noted as a summer retreat destination, and from the Showa period onward, development as a ski resort progressed. However, even with ongoing development, the rich natural environment and serene atmosphere have been preserved, and it continues to be beloved by many as a healing space away from urban bustle.
Manza Onsen’s Spring Quality and Efficacy｜Famous Hot Spring with Japan’s Highest Sulfur Content
Remarkable Sulfur Content
The greatest characteristic of Manza Onsen is the abundance of sulfur content in its water. The daily hot spring discharge reaches approximately 5.4 million liters, and its sulfur content ranks first in Japan. While there are slight differences depending on the source spring, the primary spring type is “acidic sulfur spring,” characterized by a distinctive sulfur aroma and milky-blue water.
The color of the hot spring ranges from cloudy milky blue to white, evidence of the abundant sulfur content. The pH value is approximately 2.0-2.5, making it strongly acidic, and its sterilization properties are said to be extremely high.
Primary Efficacies of Manza Onsen
Manza Onsen is particularly known as a “famous hot spring for respiratory systems” with the following reported benefits:
Respiratory System Diseases
- Bronchial asthma
- Chronic bronchitis
- Pulmonary emphysema
Skin Conditions
- Atopic dermatitis
- Chronic eczema
- Psoriasis vulgaris
Circulatory System
- Hypertension
- Arteriosclerosis
- Peripheral circulation disorders
Other Conditions
- Diabetes mellitus
- Chronic gynecological diseases
- Rheumatic diseases
- Neuralgia
- Beauty skin effects
Inhalation of hydrogen sulfide gas from sulfur springs is said to be particularly effective for respiratory system conditions, and many visitors come from across the country for therapeutic purposes.
Types of Source Springs and Their Characteristics
Manza Onsen has multiple source springs, and different accommodations use different sources:
- Nigayu (Bitter Spring): Highest sulfur content, strongly acidic
- Ryusen no Yu: Cloudy milky-white hot spring water
- Hossei no Yu: Relatively mild spring quality
- Ubayu (Grandmother’s Spring): A traditionally cherished source spring
Each source spring has subtly different colors and efficacies, so it’s recommended to visit multiple accommodations to enjoy “hot spring hopping.”
Access to Manza Onsen｜How to Get There by Car, Train, and Bus
Access by Private Vehicle
From Tokyo
- About 80km from Shikawa-Ikaho IC on the Kan-Etsu Expressway (approximately 90 minutes)
- About 65km from Usui-Karuizawa IC on the Joshin’etsu Expressway (approximately 75 minutes)
From Nagano
- About 50km from Ueda-Sugashiro IC on the Joshin’etsu Expressway (approximately 60 minutes)
During winter (late November to late April), the Manza Highway (toward Shiga Kogen) is closed to traffic, so access is only from the Tsumagoi Village side. Studless tires or chains are essential.
Access by Public Transportation
Train + Bus
- Get off at “Manza-Karasawa Guchi Station” on the JR Agatsuma Line
- Take the Seibu Kanko Bus “bound for Manza Onsen” for approximately 40 minutes
When Using the Shinkansen
- Direct Seibu Kanko Bus from Karuizawa Station on the Hokuriku Shinkansen to Manza Onsen (approximately 2 hours)
- Takasaki Station on the Joetsu Shinkansen → JR Agatsuma Line to Manza-Karasawa Guchi Station → Bus
Direct Bus
- Seasonal direct bus service from Tokyo (Busta Shinjuku) available (reservation required)
Manza Onsen Address and Basic Information
Location: Hoshimata, Tsumagoi Village, Agatsuma County, Gunma Prefecture
Elevation: Approximately 1,800m
Annual Average Temperature: Approximately 6°C (cool even in summer, severe winter cold)
Inquiries: Manza Onsen Tourism Association
Recommended Accommodations at Manza Onsen｜Characteristics and How to Choose
Manza Onsen has various unique accommodations scattered throughout. Understand each one’s characteristics and choose one that suits your purpose.
Manza Onsen Nishin-kan
A historic inn representing Manza Onsen. Its origins trace back to the late Edo period, with a long history.
Characteristics
- “Hot spring hopping inn” with 9 source springs and 9 different bathing facilities
- The open-air bath “Gokuraku-yu” at elevation 1800m offers spectacular views
- Wooden bathing tubs add nostalgic charm
- Varied plans from therapeutic stays to sightseeing
Manza-tei (Hakutetsu no Yu)
A quiet, serene inn nestled in Joshin’etsu Kogen National Park.
Characteristics
- Possesses its own unique source spring called “Hakutetsu no Yu”
- Location offers seasonal scenery
- Cuisine using Gunma prefectural ingredients is highly regarded
- Compact, relaxed atmosphere
Manza Hotel Jurac
A large hotel where you can fully enjoy the “Heaven’s Hot Spring Resort.”
Characteristics
- Spectacular open-air bath at elevation 1800m
- Eight bathing facilities for hot spring hopping
- Buffet-style meals are popular
- Ideal for families and groups
Manza Prince Hotel
A resort hotel adjacent to Manza Onsen Ski Resort.
Characteristics
- Convenient slope-side access during ski season
- Enjoy high mountain hot springs at elevation 1800m
- Modern guest rooms, mainly Western style
- Resort-style experience
Manza Kogen Hotel
A highland resort where you can experience unity with nature.
Characteristics
- “Stone Garden Open-Air Bath” is famous
- Quiet environment surrounded by nature
- Starry night sky at elevation 1800m
- Four-season activities well-developed
Toyokuni-kan
A homey inn that retains the atmosphere of traditional therapeutic hot spring accommodations.
Characteristics
- Self-catering rooms available, traditional bath house style
- Budget-friendly rates
- Accommodates long-term stays
- Recommended for those wanting to experience hot spring culture
Day-Trip Bathing Information at Manza Onsen
You can enjoy the famous Manza hot springs even without staying overnight at abundant day-trip facilities.
Facilities Offering Day-Trip Bathing
Manza Onsen Nishin-kan
- Hours: 10:00-16:00 (last admission 15:00)
- Fee: Approximately 1,200 yen for adults
- Enjoy 9 bathing facilities
Manza Hotel Jurac
- Hours: 12:00-17:00
- Fee: Approximately 1,000 yen for adults
- Hot spring hopping with 8 bathing facilities
Manza-tei
- Hours: Confirmation needed (varies by season)
- Fee: Approximately 1,000 yen for adults
Manza Prince Hotel
- Hours: 11:00-17:00 (last admission 16:00)
- Fee: Approximately 1,500 yen for adults
※Hours and fees may change; we recommend confirming with each facility beforehand.
Notes on Day-Trip Bathing
- Winter hours may change
- Capacity restrictions may apply during peak times
- Bring your own towels or purchase/rent them on-site
- High elevation requires attention to health management
Four Seasons at Manza Onsen｜How to Enjoy Each Season
Manza Onsen, positioned at elevation 1800m, reveals a completely different appearance with each season.
Spring (April-June)
Season of Fresh Greenery
- Alpine plants sprout as snow melts
- Beautiful contrast between remaining snow and new greenery
- Relatively quiet with fewer tourists
- Recommended after the Golden Week holidays
Ways to Enjoy
- Walks around Ushi Pond
- Bird watching
- Enjoy mountain vegetable cuisine
Summer (July-August)
Manza Onsen as a Summer Retreat
- Average temperature 15-20°C, cool and comfortable
- Alpine plants are at their most beautiful
- Ideal for stargazing
- Peak tourist season during summer holidays
Ways to Enjoy
- Honshirane Mountain climbing (about 2 hours round trip)
- Viewing Karabuki (volcanic steam vents)
- Highland hiking
- Night tours for stargazing
Autumn (September-November)
Famous for Fall Foliage
- Peak foliage from late September to early October
- Nanakamado and dwarf birch turn colors
- Most crowded season
- Early mornings and evenings are cold
Ways to Enjoy
- Autumn foliage open-air bathing
- Shiga-Kusatsu Road (National Route 292) autumn foliage drive
- Photography spot tours
- Mushroom cuisine
Winter (December-March)
Skiing and Snow-Viewing Hot Springs
- Winter sports at Manza Onsen Ski Resort
- Premium powder snow
- Snow-viewing open-air baths are exceptional
- Tree ice formations sometimes visible
Ways to Enjoy
- Skiing and snowboarding
- Snowshoe trekking
- Snow-viewing open-air bathing
- Winter stargazing
Tourist Attractions Around Manza Onsen
Karabuki (Volcanic Steam Vents)
A natural phenomenon symbolizing Manza Onsen. The sight of sulfur-laden steam forcefully shooting from rock faces is spectacular. A walking trail is well-maintained for close viewing.
Viewing Tips
- Round-trip time: approximately 30 minutes
- Sulfur smell is strong; those with weak respiratory systems should be cautious
- Winter snow may prevent close approach
Ushi Pond
A small pond approximately 15 minutes walk from Manza Onsen. A walking trail surrounds it, allowing enjoyment of seasonal nature.
Honshirane Mountain
An active volcano accessible for climbing from Manza Onsen. The summit offers a vast panorama including Mt. Asama and the Northern Alps.
Climbing Information
- Trailhead: Approximately 10 minutes by car from Manza Onsen
- Time required: Approximately 2 hours round trip
- Difficulty: Intermediate level
- Entry restrictions due to volcanic activity (confirmation required)
Shiga-Kusatsu Road (National Route 292)
A mountain road connecting Manza Onsen and Shiga Kogen. Particularly beautiful during fall foliage season and popular as a driving route.
Traffic Information
- Winter closure: Late November to late April
- Toll: Free
Kusatsu Onsen
About 40 minutes by car from Manza Onsen, one of Japan’s three most famous hot springs. Boasting Japan’s highest natural spring discharge, many tourists enjoy “hot spring hopping” combining it with Manza Onsen.
Karuizawa
About 1 hour by car from Manza Onsen. A highland resort where you can enjoy shopping and dining. Tourism plans combining Manza Onsen are also popular.
Manza Onsen’s Hot Spring District and Atmosphere
Characteristics of the Hot Spring District
Manza Onsen is less like a typical “hot spring town” and more like a collection of scattered hot spring inns on a 1800m highland. Rather than bustling shopping streets and souvenir shops, it features a quiet, calm environment.
Composition of Hot Spring District
- Accommodations: Approximately 10 inns
- Convenience stores and shops: None (nearest in Tsumagoi Village city center)
- Restaurants: Only in accommodation establishments
- Souvenir shops: Small ones within accommodations
Regarding Convenience
Manza Onsen retains the character of a secret hot spring, so don’t expect urban conveniences.
Important Notes
- No convenience stores or supermarkets in the hot spring district
- Recommended to purchase necessary items beforehand
- Mobile phone reception generally works for major carriers but may be unstable in some areas
- No gas stations in the hot spring district; fill up beforehand
This Inconvenience is the Appeal
Conversely, this inconvenience is the charm of Manza Onsen. It’s an ideal environment for digital detox, allowing you to focus on nature and hot springs.
How to Spend Time at Manza Onsen｜Model Courses
1 Night, 2 Days – Hot Spring Immersion Course
Day 1
- 12:00 Arrive at Manza Onsen
- 13:00 Check-in, lunch
- 14:30 View Karabuki (30 minutes)
- 15:30 Hot spring bath (1st time)
- 17:00 Rest in room
- 18:00 Dinner
- 19:30 Hot spring bath (2nd time)
- 21:00 Stargazing
- 22:00 Sleep
Day 2
- 6:00 Early morning bath
- 7:30 Breakfast
- 9:00 Ushi Pond walk
- 10:30 Check-out
- 11:00 Day-trip bathing at another facility
- 13:00 Depart
2 Nights, 3 Days – Course with Surrounding Sightseeing
Day 1
- Morning Karuizawa sightseeing and shopping
- 15:00 Arrive at Manza Onsen, check-in
- Evening-Night Hot spring indulgence
Day 2
- Morning Honshirane Mountain climbing or surrounding hiking
- Afternoon Relax in hot springs
- Night Stargazing
Day 3
- Morning Early bath, then check-out
- Afternoon Hot spring hopping at Kusatsu Onsen
- Evening Begin return journey
Important Notes When Visiting Manza Onsen
Altitude Sickness Prevention
At elevation 1800m, altitude sickness symptoms may occur.
Precautions
- Move slowly after arrival
- Drink sufficient water
- Limit alcohol consumption
- Practice conscious deep breathing
- Avoid overexertion if experiencing headache or nausea
Climate and Clothing
Cool Even in Summer
- Even in summer (July-August), temperatures may drop below 10°C in mornings and evenings
- Long-sleeved outer garments are essential
- Strong daytime ultraviolet rays require sun protection
Extreme Cold in Winter
- Winter (December-March) can reach below -20°C
- Thorough cold-weather gear necessary
- Road surfaces will be frozen
Packing Checklist
- Cold weather clothing (regardless of season)
- Sunscreen and sunglasses
- Medications (including altitude sickness remedies)
- Flashlight (for nighttime movement)
- Beverages and snacks (no nearby stores)
- Studless tires or chains (winter)
Regarding Reservations
Book Early During Peak Season
- Fall foliage season (late September to early October)
- Golden Week
- Obon holidays
- Year-end and New Year holidays
During these periods, accommodations often fill up several months in advance.
Manza Onsen Reviews and Evaluations
Overall Satisfaction Trends
Reviews from Manza Onsen visitors show high praise for the following points:
Highly Evaluated Points
- Excellent spring quality (sulfur spring benefits)
- Spectacular views at elevation 1800m
- Quiet, calm atmosphere
- Open-air bath sense of openness
- Beautiful starry skies
- Four-season nature
Points Requesting Improvement
- Inconvenient lack of nearby shops
- Winter access difficulties
- Mobile phone reception
- Somewhat high accommodation prices
Reviews on Hot Spring and Water Characteristics
Comments like “strong sulfur aroma gives sense of authentic hot spring,” “skin became very smooth,” and “respiratory condition improved” indicate very high satisfaction with spring quality.
Conversely, some note that “strong sulfur smell isn’t for everyone” and “those with sensitive skin should be careful of high acidity.”
Reviews on Resort Atmosphere and Convenience
Many positive comments include “forget urban hustle and bustle” and “perfect for digital detox,” while some point out inconveniences like “no shopping available” and “dining only at accommodations.”
However, most visitors embrace this “inconvenience” as the appeal of a secret hot spring, and many intentionally seek it out.
Manza Onsen and Kusatsu Onsen Hot Spring Hopping
Gunma Prefecture’s two major hot springs, Manza and Kusatsu Onsen, are about 40 minutes apart by car. “Hot spring hopping” enjoying both is popular.
Differences Between the Two Hot Springs
Manza Onsen
- High altitude of 1800m
- Quiet, calm atmosphere
- Japan’s highest sulfur content
- Secret hot spring character
- Approximately 10 accommodations
Kusatsu Onsen
- Approximately 1200m elevation
- Bustling hot spring town
- Japan’s highest natural discharge
- Tourist convenience
- Over 100 accommodations
Recommended Touring Plan
2 Night, 3 Day Plan
- 1st night: Manza Onsen for quiet hot spring immersion
- 2nd night: Kusatsu Onsen for town exploration and hot spring hopping
- Experience contrasting two hot spring resorts
Day-Trip Combination
- Morning: Day-trip bathing at Manza Onsen
- Afternoon: Kusatsu Onsen sightseeing at Yumotaike and day-trip bathing
- Experience two famous hot springs in one day
Conclusion｜Thoroughly Enjoying Manza Onsen’s Charms
Manza Onsen is located at elevation 1800m, Japan’s highest altitude, and boasts Japan’s highest sulfur content. As the “Heaven’s Hot Spring Resort,” it was selected as Japan’s #1 in the Hot Spring Grand Prix’s “Secret and Famous Hot Springs” category for two consecutive years, with its spring quality and environment highly evaluated nationwide.
While it lacks urban conveniences, this is precisely what offers its greatest appeal: the tranquility, magnificent nature, starry skies, and above all, wonderful hot springs.
Manza Onsen presents different faces with each season: spring greenery, summer retreat, autumn foliage, and winter snow-viewing hot springs. Whenever you visit, there are seasonal pleasures to enjoy.
When visiting Gunma Prefecture, please take time to refresh body and spirit at Manza Onsen. This heaven’s secret hot spring at elevation 1800m will surely heal daily fatigue and provide new vitality.
Reservation and Inquiry Information
When planning a trip to Manza Onsen, you can book directly with each accommodation or through major travel reservation sites. Since road conditions and operating hours vary by season, we recommend checking the latest information on the Manza Onsen Tourism Association’s official website.
Manza Onsen, Gunma Prefecture’s boasted secret hot spring at elevation 1800m in the heavens. Please enjoy a special hot spring experience here.
