Kusatsu Onsen

Kusatsu Onsen boasts the largest natural hot spring output in Japan, with more than 32,300 liters gushing forth every minute, and has been selected as one of Japan’s three most renowned hot springs. It is famous for its highly effective spring water, long said to be able to cure anything except matters of the heart.

Its sulfur-scented spring water is smooth and gentle on the skin, and it is also well known as a beautiful-skin bath. The highly acidic water, among the strongest in Japan, has strong antibacterial effects and naturally cleanses the skin, leaving it radiant and lustrous. Another pleasure of visiting is strolling through the hot spring town, lined with foot baths, souvenir shops, and restaurants. In addition to the area centered around Yubatake, Kusatsu’s iconic landmark, a new attraction called “Ura Kusatsu” was created in 2021 in the Jizo district just a few minutes’ walk from Yubatake, adding even more highlights to see.

▶ Features of Kusatsu Onsen
All of the springs are naturally gushing self-flowing hot springs, and the water is strongly acidic. Although there are said to be several dozen spring sources, some are privately owned; most are owned or managed by the town. The seven representative sources are Bandai Spring, Yubatake Spring, Shirahata Spring, Jizo Spring, Sai no Kawara Spring, Nigawa Spring, and Netsu no Yu Spring.

▶ Spring quality
The quality of the water varies slightly from spring to spring, but the main type is an acidic, hypotonic, high-temperature spring with a pH of around 2.0. It is so strongly acidic that if a five-sun nail is left in the Yubagawa River, it will dissolve and disappear in about ten days.

Among the springs, Bandai Spring gushes out at an especially high temperature of about 94.5°C, so it is used in baths after being cooled to about 54°C through heat exchange with tap water using a plate heat exchanger. The other springs emerge at around 50°C and have traditionally been used directly for bathing.

Among the representative springs, Yubatake Spring gushes up from the plaza in the center of town, delighting visiting tourists.

In addition, the hot spring is used effectively for road snow melting and indoor heating in public facilities, making good use of its thermal energy.

▶ Public baths
Nineteen public baths are located at convenient spots throughout the town and are open free of charge, for use not only by residents but also by visitors.