Netsunoyu in Kusatsu Onsen is where you can witness the traditional Yumomi performance.

Yumomi is a unique method of cooling down hot spring water that’s too hot to bathe in directly. Instead of adding cold water, which would dilute its beneficial minerals, the water is stirred with large wooden paddles. This stirring process not only cools the water but also evenly distributes the minerals, creating the perfect balance for bathing.

The entrance fee is 700 yen, and don't forget to check the schedule on their website to plan your visit.