For a day by the water with a difference, make your way to the steaming pools of Shiriyaki Onsen. This place is famous for its mineral-rich thermal waters.
If you're staying a while in Nakanojo, Shiriyaki Onsen is a good place to kick off your sightseeing. This naturally heated water source is one of numerous attractions that'll keep you on the hop here. Yubatake, Kusatsu Onsen Ski Resort, and Sainokawara Park are also waiting to be explored close by.