Located in western Gunma Prefecture, Kusatsu Onsen is renowned as one of the “Three Great Hot Springs of Japan,” along with Arima Onsen in Hyogo and Gero Onsen in Gifu. While all three boast rich histories and exceptional water quality, Kusatsu stands out for several distinct reasons that continue to attract visitors across generations.

One of the most remarkable features of Kusatsu is its abundant flow of natural hot spring water. Over 30,000 liters gush forth every day, making it one of the most prolific hot springs in Japan. With over 100 different sources, nearly every inn in the area offers pure, unadulterated gensen kakenagashi—hot spring water flowing directly from the source without added water—an especially prized experience for onsen enthusiasts.

Another defining characteristic is its unique water composition. Kusatsu’s springs are strongly acidic, with a pH level around 2, giving them powerful antibacterial properties. The water is said to be effective in treating skin conditions and minor wounds, and has long been praised for its broad therapeutic benefits. During the Edo period, Kusatsu flourished as a healing retreat for samurai and scholars, many of whom left written records of their visits.

At the heart of the town lies its most iconic feature: the Yubatake, or “hot water field.” Over 4,000 liters of steaming water flow through wooden channels here every minute. This dramatic display of rising steam and traditional wood structures used to cool the water creates a captivating scene. By night, the Yubatake is beautifully illuminated, enveloping the area in a dreamlike, atmospheric glow.

Another hallmark of Kusatsu Onsen is its unique yumomi tradition—a cultural practice developed to cool the high-temperature spring water without diluting it. Long wooden paddles are used to stir the hot water rhythmically, allowing it to reach a comfortable bathing temperature. This technique has been passed down through generations as part of Kusatsu’s distinctive onsen heritage. Today, visitors can enjoy yumomi shows at local venues and even try the experience themselves.

Kusatsu offers a wide range of experiences for every kind of traveler. The onsen town features a mix of long-established traditional inns and stylish modern hotels, accommodating diverse needs and tastes. Public footbaths and communal bathhouses are scattered throughout the area, making it easy to enjoy the healing waters at any time. Beyond the baths, Kusatsu is surrounded by natural attractions such as the volcanic terrain of Mount Shirane, ski resorts, and scenic parks—ensuring year-round appeal.

Kusatsu Onsen’s reputation as one of Japan’s Three Great Hot Springs is well-earned. Its abundant natural water, powerful and therapeutic qualities, centuries-old traditions, and thoughtful integration of modern amenities create a rare balance. It remains a cherished destination where visitors can experience the very essence of Japan’s onsen culture.