Manza Onsen — relief & relaxation | Compare & book inns

Overview

Manza Onsen is one of Japan's premier high-altitude hot spring resorts, located within Joshin'etsukogen National Park near the border of Gunma and Nagano prefectures. Often called "the closest onsen to the stars" due to its 1,800-meter elevation, its history dates back to the late Edo period. It has long been known as a therapeutic spa (toji) for healing various ailments.

The steam rising from the "Karabuki" source area is a symbolic sight of Manza Onsen. With an impressive daily output of 5.4 million liters, the onsen is characterized by its milky-white to yellowish-green water and a distinct sulfur aroma. Surrounded by magnificent nature that changes with the seasons, you can fully experience the earth's blessings.

Primary Spring Qualities and Indications

Its most defining feature is the highly acidic sulfur spring, which has the highest sulfur concentration in Japan. With a pH of around 2.4, the strong acidity is said to have high sterilizing properties. The abundant sulfur content promotes blood circulation and has a peeling effect that removes old skin cells, earning it the name "beauty-enhancing water" (bihada-no-yu). This quality is also thought to help stimulate the immune system.

• Atopic dermatitisManza's waters are both highly acidic and rich in sulfur, a combination known to be beneficial for various skin conditions. The spring's strong sterilizing effect may help soothe inflammation and improve the skin's barrier function for those with this chronic condition.
• Psoriasis vulgarisAs a "sulfur spring," Manza Onsen is traditionally sought out for skin ailments. The high sulfur content, the highest in Japan, may help soften and reduce the scaly patches characteristic of psoriasis while soothing underlying inflammation.
• Impaired glucose tolerance (Diabetes)Sulfur springs like Manza are indicated for "lifestyle-related diseases," a category that includes diabetes. Bathing in the mineral-rich water is believed to improve peripheral circulation and metabolism, which may offer supportive benefits for managing blood sugar levels.
• Chronic eczemaThe spring's potent combination of acidity and Japan's highest sulfur concentration provides a strong sterilizing action. This may help manage the persistent inflammation and itchiness associated with chronic forms of eczema.
• Rheumatoid arthritisThe warmth of the hot spring provides immediate relief for stiff and painful joints. Furthermore, the high concentration of sulfur in Manza's water is believed to have anti-inflammatory properties that may help alleviate the chronic joint inflammation of rheumatoid arthritis.

Water Characteristics and Best Season to Visit

The source temperature is high, around 80°C (176°F), and most facilities offer it as "gensen kakenagashi"—free-flowing from the source without added water or heating. The milky-white water changes color upon contact with air, sometimes appearing bluish or greenish. The sulfur components coat the skin, keeping the body warm and preventing post-bath chills.

While enjoyable year-round, the scenery is particularly stunning in early summer (June-July) with alpine flowers in bloom, and in autumn (late Sept-mid Oct) when the mountains are ablaze with color. In winter, it transforms into a ski resort with some of Japan's best powder snow, offering the exceptional experience of an open-air bath while viewing the snow (yukimi-buro).

Access

Nearby Sightseeing and Local Cuisine

• Manza Onsen Yubatake: A 'hot water field' where you can see the source spring up close.
• Karabuki: The symbol of Manza, where volcanic steam vents white smoke.
• Manza Highway: A scenic driving route with beautiful views in every season.
• Shiga-Kusatsu Kogen Route: A popular route passing the highest point of any national highway in Japan (closed in winter).
• Tsumagoi Cabbage: Sweet and tender highland cabbage, in season from summer to autumn.
• Sweet-simmered Hanain-gen Beans: A local dish made from beans grown at high altitudes.
• Maitake Mushroom Dishes: Aromatic local maitake mushrooms served as tempura or in kamameshi (kettle rice).
• Kusatsu Onsen: One of Japan's three most famous onsen, about a 40-minute drive away for a day trip.