Kusatsu Onsen is one of Japan's most famous hot spring resorts and is blessed with large volumes of high quality hot spring water said to cure every illness but lovesickness.
Well known as a hot spring resort for many centuries, Kusatsu's fame was further boasted by German doctor Erwin von Baelz, who served at the imperial court in the late 1800s and recommended Kusatsu for its water's health benefits.
Kusatsu is situated at an altitude of 1200 meters above sea level in the mountains of Gunma Prefecture, and offers skiing in winter and hiking during the rest of the year to be enjoyed in combination with hot spring bathing.
Kusatsu has the largest natural flow of hot spring water in all of Japan, much of which surfaces at the yubatake in the town center. The sulfurous, highly acidic waters have been considered among Japan's best for centuries, and the resort town has constantly occupied a top spot in onsen rankings. It is difficult to beat Kusatsu in terms of quality and quantity of its waters.
Kusatsu's waters can be enjoyed at the town's public baths and ryokan. The most prominent public baths are the Sainokawara Rotemburo (large outdoor pools in Sainokawara Park) and the Otakinoyu with its unique Awaseyu baths that features multiple wooden pools with different water temperatures.
Besides these two large public baths, there are more than a dozen small community bath houses scattered around town that can be used for free by both the locals and tourists. They tend to have small, gender separated pools that typically sit only 2-4 persons and are filled with very hot water.
Two of the small community bath houses offer a special bathing experience called jikanyu (lit. timed bath), a bathing therapy unique to Kusatsu, where a group of bathers bathe in very hot water (typically around 48 degrees Celsius) for exactly three minutes. The hot water's benefits include opening your pores and increasing blood flow within your body and to your brain.
Of course, Kusatsu's waters can also be enjoyed at ryokan baths across the town. While staying guests can use the baths for free during their entire stay, some ryokan also open their baths to non-staying visitors during daytime for an admission fee of typically 500 to 1500 yen.
Lastly, there are a few foot baths (ashiyu) found in town that can be used freely by tourists. One of them stands next to the yubatake, while another can be found just outside the bus terminal building.
Other bath related attractions in Kusatsu are the Onsen Museum on the third floor of the bus terminal, displaying the history of onsen and Kusatsu town, and Yumomi, a traditional method of cooling down the hot spring water to bathing temperature that includes dancing and singing. Performances are held daily and can be viewed at Netsunoyu.
The Yubatake (lit. "hot water field") is the symbol of Kusatsu and one of the resort's main sources of hot spring water. In fact, with an output of 5000 liters per minute, the yubatake ranks among Japan's single most productive hot spring sources.
After bubbling to the surface at a temperature of more than 70 degrees Celsius and with a pleasant sulfur odor, the hot spring water is cooled down in the yubatake's wooden conduits by a few degrees before it gets distributed to the various ryokan and public baths.
Many ryokan and shops are clustered around the yubatake and there is a steady stream of visitors, many of whom wear yukata and geta (traditional sandals) in the evening when the yubatake is lit up. There is also a foot bath (ashiyu), that can be used for free.
Yumomi is a traditional method of cooling down hot spring water to bathing temperature by stirring the water with large wooden paddles. The process is accompanied by the singing of a local folk song.
A yumomi performance for tourists is held daily in the Netsunoyu Bath House just next to the yubatake. The performance includes a yumomi and dance performance, and several people from the audience have the opportunity to partake in yumomi.