Kusatsu Onsen — Kantō | Shared Latitude

A hot-spring town high in the Gunma mountains, built around a steaming field of scalding water that pours through the middle of the streets. Sulphur in the air, snow on the roofs, and women singing as they cool the water by hand with wooden paddles.

You smell Kusatsu before you see it. We came up on the bus from the valley, climbing through pine forest into thinner, colder mountain air, and somewhere on the last bends the sulphur reached us — that eggy, mineral, unmistakable hot-spring smell that told Lia, who had been asleep, exactly where we were before she opened her eyes. Kusatsu is one of the three or four great onsen towns of Japan, and unlike the discreet ones that hide their springs behind screens, it puts its water right in the middle of everything.

The hot-water field

The centre of town is the yubatake — literally “hot-water field” — and it’s the strangest, best town square I’ve stood in. Scalding spring water, over ninety degrees at the source, gushes up and is run through long open wooden troughs down the middle of a stone basin, cooling and depositing pale yellow-grey sulphur as it goes, before pouring off a low fall in a permanent cloud of steam. The whole thing steams and reeks and glows, lit at night, with the town’s inns and shops ranged around it. We stood at the rail a long time. There is something deeply satisfying about a town organised entirely around the thing coming out of the ground, making no attempt to hide it or apologise for it.

The steaming central yubatake of Kusatsu Onsen, long wooden channels carrying pale sulphur-rich water through a stone basin with clouds of steam rising

Yumomi — cooling the water by hand

Kusatsu’s water comes out too hot to enter, and rather than dilute it with cold — which would weaken the minerals the whole place is famous for — the old solution was to cool it by hand. This is yumomi: teams of women stir and beat the water with long flat wooden paddles, working it back and forth to bring the temperature down, and they do it in time to a folk song, the Kusatsu-bushi, which they sing as they work. We caught a demonstration at the Netsu-no-Yu hall — half performance now, half preservation of a real technique — and it was oddly moving: the rhythm of the paddles, the steam, the old melody, a whole ritual grown up around the simple problem of water that loves you a little too fiercely.

Women in traditional dress stirring steaming hot-spring water with long wooden paddles inside a wooden bath hall in Kusatsu

The bath itself

And then, of course, you bathe. We soaked at Sainokawara, a big open-air rotenburo set in a park at the edge of town where hot streams run down the hillside, and I lowered myself into water that was, even cooled, at the very outer edge of what I could stand — Kusatsu water is strong, acidic enough to sting a cut and, they say, to kill most things it touches. I lasted a proper Japanese few minutes, red as a boiled crab, and climbed out into the freezing mountain air with my skin singing. Lia stayed in longer, of course, and emerged looking annoyingly serene. We walked back through the snow to our inn with wet hair and no need of coats, warm from the inside out in a way no radiator has ever managed.

The open-air Sainokawara rotenburo bath at Kusatsu set among snow and rock, steam rising off the pale mineral water at the edge of town

Getting There

Kusatsu Onsen sits high in the mountains of Gunma, north-west of Tokyo. The usual route is the JR limited express from Ueno toward Naganohara-Kusatsuguchi Station (around two and a half hours), then a JR bus up the last winding half-hour to the town’s bus terminal. Direct highway buses also run from Tokyo Station and Shinjuku in roughly four hours. The town centre around the yubatake is small and walkable once you arrive. Come in winter for snow and steam, but pack for real mountain cold.