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Kusatsu Yubatake with hot water pouring from wooden channels into a turquoise pool, inns around it
Photo: くろふね, CC BY-SA 4.0, via Wikimedia Commons
Gunma · onsen

Kusatsu Onsen Yubatake

草津温泉湯畑

Kusatsu Onsen's steaming symbol, gushing about 4,000 litres of hot water a minute. Lit up at night, its light and steam make a magical scene.

Pale green hot spring water flowing over the rocks of Yubatake in the center of Kusatsu town
Photo: くろふね, CC BY-SA 4.0, via Wikimedia Commons
Steam rising from the wooden channels of Yubatake in Kusatsu Onsen
Photo: KΛNΛTΛ, CC BY-SA 3.0, via Wikimedia Commons

A "hot water field" in the heart of town

The Yubatake (literally "hot water field") is a hot spring source right in the centre of Kusatsu Onsen, in the town of Kusatsu, Gunma Prefecture. About 4,000 litres of hot spring water gush out here every minute, and it has become the symbol of the onsen (hot spring) town. Souvenir shops and restaurants line the streets around it.

Across Kusatsu Onsen as a whole, more than 32,300 litres of water flow out naturally every minute, said to be the largest natural flow in Japan. The water contains sulphur and is strongly acidic: according to the Kusatsu Onsen Tourism Association, the Yubatake source has a pH of 2.1, one of the most acidic in Japan.

Wooden channels that cool the water

The water comes out of the Yubatake at about 52°C, far too hot to bathe in. So it is sent down seven wooden channels called yudoi (a toi is a long, narrow trough for carrying water), which gradually bring the temperature down before the water is piped to ryokan (traditional inns) and public baths.

As the water flows, minerals from the spring solidify into yunohana ("hot water flowers"), which are collected a few times a year and sold as a Kusatsu souvenir. It is said that the name "Yubatake" comes from this "harvesting" of yunohana. In 2017 the site was also designated a national Place of Scenic Beauty.

Watch yumomi, or try it yourself

About a minute's walk from the Yubatake, in a building in the romantic style of the Taisho era called Netsunoyu, you can watch yumomi, a Kusatsu tradition. Yumomi is an old method devised to bring spring water that is too hot to bathe in down to just the right temperature.

Netsunoyu stages shows that combine yumomi with song and dance, and also offers a chance to try yumomi yourself. Check show times on the official website.

The Yubatake at night, and getting there

At night the Yubatake is lit up, and the illuminated steam looks truly magical. Kusatsu town's tourist information recommends visiting around dusk.

By train, take the Kusatsu limited express from Ueno Station to Naganohara-Kusatsuguchi Station, then a local bus for about 25 minutes to the Kusatsu Onsen Bus Terminal. There is a tourist information centre on the ground floor of the bus terminal.

Tips

  • The water in the Yubatake is for looking at. If you want to bathe, use the public baths or day-use bathing facilities around it. There is also a footbath, Yukemuritei, near the Yubatake.
  • A walkway lined with a stone fence runs around the Yubatake. After your bath, take a leisurely stroll around it.
  • It feels completely different by day and by night. If you are staying over, go back to see it lit up after dark.

Sources

Updated 28 September 2026. Opening hours and prices change, so check the official site before you go.

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