Yubatake is the town's hot-water field, a set of wooden channels carrying scalding, mineral-heavy spring water through the middle of Kusatsu. Steam rises constantly, especially in cold weather, and the smell of sulphur hangs over the square.
It is both an industrial-looking spring works and the town's social centre. Come early before the day-trippers arrive, then return after dark when the steam and lights make the place feel more dramatic.