Kusatsu Onsen
Where Japan's Best Hot Spring Waters Flow
Kusatsu Onsen has been celebrated as one of Japan's three greatest hot springs for over 1,000 years, alongside Gero and Arima. The town was discovered in ancient times and became famous during the Edo period when shogun Tokugawa Yoshimune had its waters transported to Edo Castle for bathing. The town's motto, 'Kusatsu no yu wa, koi no yamai igai wa naosanai byoki wa nai' (Kusatsu's waters cure all illnesses except love sickness), reflects its legendary healing reputation.
The town developed around the Yubatake ('hot water field'), a wooden channel system where 32,000 liters of hot water per minute gushes from the source at 55-95°C. The iconic Yubatake, with its steam rising dramatically, was constructed in the Edo period to cool the extremely hot water before it enters the public baths. The water's high acidity (pH 2.1) gives it powerful antibacterial properties and a distinctive sulfur smell.
Kusatsu pioneered the yumomi tradition - using large wooden paddles to cool and circulate the water while singing traditional songs. This performance, now done for tourists at Netsunoyu, was originally a practical necessity because diluting the potent water would reduce its medicinal properties. Today, Kusatsu remains a living hot spring resort where the tradition of jikan-yu (time baths - long soaking sessions under supervision) continues at public baths like Jizo-no-yu.
Key Highlights
- Yubatake - iconic steaming hot water field in town center
- Highest volume hot spring discharge in Japan (32,000L/min)
- Highly acidic healing water (pH 2.1) with therapeutic properties
- Traditional yumomi paddle performances at Netsunoyu
- Free public baths and foot baths throughout town
- Mountain resort town at 1,200m elevation with ski resort
Access Information
Location
Kusatsu, Agatsuma District, Gunma 377-1711, Japan
Nearest Stations
- • Naganohara-Kusatsuguchi Station (JR Agatsuma Line - then bus)
Opening Hours
Town: 24 hours | Public baths: typically 7:00-21:00 | Yumomi shows: 9:30-16:30 (varies)
Admission Fee
Town: Free | Public baths: Free-¥500 | Yumomi show: ¥700 | Sainokawara Park bath: ¥600
How to Get There
From Tokyo
JR Limited Express Kusatsu to Naganohara-Kusatsuguchi, then JR bus (25 min)
2.5 hours
From Tokyo (Shinjuku)
Highway bus directly to Kusatsu Onsen bus terminal
4 hours
From Karuizawa
Kusatsu Kogen Line bus (grassland route, seasonal)
1.5 hours
Tips & Visiting Guide
Make the most of your visit with these helpful tips and guidelines.
Try Multiple Public Baths
Kusatsu has 19 free or low-cost public baths, each with unique character. Must-tries: Jizo-no-yu and Chiyo-no-yu (free, traditional), Goza-no-yu (¥500, near Yubatake), and Sainokawara Rotemburo (¥600, huge outdoor bath in park). Bring your own towel or rent one. No tattoos in most public baths.
See the Yumomi Performance
The traditional yumomi (water-stirring) show at Netsunoyu demonstrates how locals cooled the scalding 50°C water using wooden paddles while singing folk songs. Six daily shows (¥700). You can also try yumomi yourself afterward. It's touristy but represents genuine Kusatsu tradition.
Stay Overnight for Full Experience
Kusatsu deserves an overnight stay to experience multiple baths, evening town atmosphere, and morning yuzampo (hot spring walk). Many ryokan offer in-house onsen and kaiseki meals (¥15,000-40,000 per person). Budget hotels with shared onsen available from ¥8,000.
Yubatake is Most Photogenic at Night
The steaming Yubatake is beautiful anytime but spectacular at night when illuminated, with steam rising dramatically into cold mountain air. Early morning also offers magical atmosphere with fewer crowds. The surrounding traditional buildings create a perfect frame.
The Water is Seriously Acidic - Take Care
Kusatsu's pH 2.1 water is highly acidic (similar to lemon juice). Don't soak too long (10-15 min max), rinse any cuts immediately, remove jewelry/watches (they'll corrode), and shower after bathing. The intensity is part of the therapeutic benefit but requires respect.
Explore Sainokawara Park
Beautiful 10-minute walk from Yubatake through Sainokawara Park, where hot springs bubble up naturally. The park culminates in Sainokawara Rotemburo (¥600), one of Japan's largest outdoor baths (500 sqm) surrounded by nature. The walk itself shows the volcanic landscape.
Excellent Winter Destination
Kusatsu Kokusai Ski Resort (nearby) offers excellent skiing/snowboarding. The combination of winter sports and hot springs is perfect. The town is magical in snow, with steaming yubatake creating dramatic winter scenes. Hotels less crowded than summer/autumn (except New Year).
Try Onsen Tamago and Local Foods
Onsen tamago (eggs cooked in hot spring water) sold around Yubatake. Try local beef, mountain vegetables, and hearty noodles. Café restaurants around the yubatake offer meals with steam views. The acidic water also produces unique tea flavors at local cafes.
FAQ
How long should I stay in Kusatsu?
Overnight is minimum to enjoy the baths properly. Two nights allows trying multiple bath houses and relaxing pace. Day trips are possible but rushed.
What is the Yubatake?
The 'hot water field' is Kusatsu's symbol - a wooden structure channeling hot spring water to cool it naturally. It's beautifully illuminated at night. The sulfur smell is strong but adds atmosphere.
Can I bathe with tattoos?
Most public baths prohibit tattoos. Some ryokan allow tattooed guests in private baths. Sainokawara open-air bath sometimes allows covered small tattoos. Check specific policies.
What's special about the water?
Kusatsu has Japan's most acidic hot springs (pH 2.1), believed to cure various ailments. The water is so acidic it can dissolve a nail in a week. Don't wear jewelry while bathing.
Which public bath should I try?
Otakinoyu offers traditional architecture. Sainokawara has huge outdoor baths. Goza no Yu provides the yumomi water-stirring show experience. Each has unique character.
What is yumomi?
Traditional method of cooling hot spring water by stirring with wooden paddles while singing folk songs. Shows are performed several times daily. Visitors can try it themselves.
Are there activities besides bathing?
Skiing in winter, hiking in summer, shopping for hot spring eggs and local crafts. The Netsunoyu building hosts yumomi performances. Evening strolls around illuminated Yubatake are romantic.
Is it crowded?
Weekends and holidays are busy. The town is compact, so it can feel crowded at peak times. Weekdays offer more relaxed atmosphere. Book accommodation well in advance.
What should I eat here?
Try onsen manju (steamed buns), eggs boiled in hot springs, and local mountain vegetables. Many restaurants serve hearty warming dishes perfect after bathing.
How do I get there from Tokyo?
Direct highway bus (4 hours) or train to Naganohara-Kusatsuguchi then bus (3.5 hours total). The scenic bus route through mountains is part of the experience.
Nearby Attractions
Explore more wonderful destinations in the same prefecture.
Ikaho Onsen
A historic hot spring town built on a mountainside, famous for its iconic 365-step stone staircase lined with traditional ryokan, shops, and two types of therapeutic spring water.
Minakami Onsen
A collection of hot spring resorts in the mountains north of Tokyo, famous for outdoor adventure sports, river rafting, and traditional ryokan hospitality.
Oze National Park
A pristine highland marshland famous for wooden boardwalks through flowering wetlands, mirror-like ponds, and some of Japan's most spectacular alpine scenery.
Takaragawa Onsen
Japan's largest outdoor mixed-gender hot spring bath along a pristine mountain river, featuring rustic wooden ryokan architecture and therapeutic waters in a remote mountain valley setting.