The Yumomi technique was developed in the Edo period because the source water at Kusatsu reaches temperatures up to 90 degrees Celsius.
The wooden paddles used in the performance are approximately 1.8 meters long.
The rhythmic song accompanying the performance, 'Kusatsu Bushi', is a traditional folk song that helps performers maintain the cooling cadence.
Water is stirred specifically to mix the minerals and reduce the scalding heat without adding external water, which would lower the concentration of the spring's medicinal properties.
Netsunoyu translates to 'Hot Water Bathhouse'.
The building was reconstructed in 2015 to house the current performance theater while maintaining its historic function.
Kusatsu Onsen Netsunoyu is a traditional performance venue dedicated to the Yumomi, a historical water-cooling method used to lower the extreme heat of Kusatsu's natural spring water without diluting it with cold water. Performers clad in traditional kimonos use large wooden paddles to churn the water, cooling it to a temperature suitable for bathing. This practice serves to maintain the therapeutic quality of the acidic, high-temperature volcanic spring water. The facility features a central wooden pool where these demonstrations take place, surrounded by tiered spectator seating. It is situated directly adjacent to the Yubatake, the town’s primary landmark and central hot spring source. The venue serves as the cultural heart of the town, preserving a traditional custom that has been performed for generations. Visitors can occasionally participate in the Yumomi performance experience following the professional demonstration. The architecture of the building reflects a modern interpretation of a classic Japanese bathhouse aesthetic.
The front-row seating area looking down into the wooden pool during the climax of the performance.
Arrive early to secure a seat in the lower rows for a better view of the wooden paddle techniques.
Check the performance board upon entry, as they offer limited slots for tourists to try the Yumomi paddles themselves.
Keep your camera ready during the final song when the performers stir the water vigorously to create high-velocity currents.
Do not attempt to touch the water in the Yubatake source outside the venue, as it is dangerously hot.
Occasionally closed for facility maintenance; check local schedules for irregular holiday closures.
Remove shoes at the entrance and place them in the provided lockers; refrain from touching the spring water unless invited to participate.
