Yubatake: The Steaming Heart of Kusatsu Onsen
Seven wooden conduits, each around forty meters long, run side by side down a stone-walled basin in the center of Kusatsu. Through them slides hot spring water at about 52°C, surfacing at a pace of roughly 4,040 liters every minute. By the time the water leaves the far end of the conduits, it has cooled enough to flow into a small cliff and crash down as a "yutaki" — a hot spring waterfall — before being piped out to the inns and public baths that ring the town.
This is the Yubatake, literally the "hot water field," and it is the visible center of Kusatsu Onsen. The basin covers 1,112 square meters inside its low stone fence. Steam lifts from the surface all year, dense in the cold months, lazy and shimmering in summer. Almost every road in the old town points toward it.
Kusatsu is one of Japan's three most famous hot spring towns, along with Arima in Hyogo and Gero in Gifu. Its waters are strongly acidic — pH around 2.0 — and the town has long claimed Japan's largest natural outflow of hot spring water by free-flowing volume. The Yubatake is the single source most directly responsible for that reputation.
From "Pond of Flowers" to "Hot Water Field"
The Yubatake's site has been producing hot, mineral-rich water for at least a thousand years, long before Kusatsu became a documented town. During the Edo period it was known as Oike, the "great pond," or as the Yu-no-hana-no-ike, the "pond of the hot spring flowers" — a reference to the pale, soft sulfur sediment that settles wherever the water meets the air. The basin was hemmed in by wooden palings then, and from it residents and travelers drew water for bathing.
Wooden conduits in the modern arrangement were first installed in 1887 (Meiji 20), and the new name "Yubatake" — a "field" cultivated for harvesting yu-no-hana sediment — caught on shortly afterward. The harvest itself is older. Records indicate that yu-no-hana has been collected at the site since around the Kansei era of the late 18th century. Today it is gathered a few times a year, dried for about a month, packed into small containers, and sold in shops around the town.
The shoguns of Edo took an early interest. The Tokugawa Bakufu's records describe water being drawn from the central enclosure here and carried in casks to Edo Castle in Kyoho 11 (1726) and again in Kanpo 3 (1743), reportedly for the bath of the eighth shogun, Yoshimune. A wooden frame survives in the basin as the "Yo-kumiage-no-yu-waku," the shoguns' drawing-up site, said to date to that period.
A National Scenic Beauty
On 13 October 2017, the Minister of Education, Culture, Sports, Science and Technology added the Yubatake to the national register of designated cultural properties under the category of meisho — Place of Scenic Beauty. The official rationale is concise: a hot spring source landscape of unequaled type, sitting at the center of Kusatsu Onsen, whose visual character expresses the bathing culture of the place.
The designation covers more than just the water. It includes the gourd-shaped stone enclosure, the bank of seven conduits, the rough wooden frame of the shoguns' drawing-up site, and the rocky cliff over which the water falls as the yutaki. Together they read as a working landscape rather than a viewing platform — a piece of public infrastructure that happens to be one of the most photographed views in Japan.
An earlier honor came in 2002, when the site was named one of Japan's "100 Best Fragrant Landscapes" by the Ministry of the Environment. The smell of sulfur drifting through the streets is, in Kusatsu, considered part of the experience rather than something to apologize for.
The Okamoto Taro Layout
The present gourd-shape and the surrounding stone walkway are the work of the artist Taro Okamoto and his Institute of Contemporary Art, completed in 1975. Okamoto, who designed the giant Tower of the Sun for Expo '70 in Osaka, was a frequent visitor to Kusatsu — he liked the skiing as much as the baths. When the town's mayor asked him to remake the area around the Yubatake into a place where people could linger rather than just pass through, Okamoto accepted.
The result reshaped what had been a more or less rectangular Edo-period basin into a soft double-curve, ringed by a wide stone promenade. Inscribed into the stones of the perimeter fence are the names of one hundred people connected to Kusatsu over its history — from the legendary Yamato Takeru and the warlord Maeda Toshiie to twentieth-century writers and film stars. The selection was made in 2000 to mark the town's centennial as a municipality. A 101st name was added in 2014: Lucius Modestus, the time-traveling Roman bathhouse architect of the film Thermae Romae II, parts of which were shot at the Yubatake.
What to Look For
Walk the perimeter slowly and you'll notice the water changing color as it travels. At the source frame near the lantern, it comes up almost clear. By the time it has run thirty or forty meters through the wooden conduits, it has taken on a pale milky-blue cast as the sulfur compounds react with the air. The white deposit on the floor of the basin is the same yu-no-hana that ends up in souvenir packets.
The conduits themselves are not decorative; they are a working method of cooling. Water that emerges at 50–55°C is too hot to bathe in. Rather than dilute it — and lose the mineral concentration that gives Kusatsu's springs their reputation — the town has historically used a combination of these long open troughs and the yumomi technique, in which long wooden boards are dragged through the bath to mix in air and bring the temperature down. The yumomi demonstration is performed daily at Netsu-no-Yu, the bath house facing the Yubatake.
The basin is lit at night until around 25:00 — through the early hours of the morning by Japanese reckoning — and the steam takes on a different quality once the surrounding shops close down. The walk between dusk and dinner is often quieter than the daytime crowd suggests it might be.
Around the Yubatake
Three small public bathhouses sit within a minute's walk of the basin and welcome visitors: Shirahata-no-Yu (associated with Minamoto no Yoritomo), Chiyo-no-Yu, and Jizo-no-Yu. Each runs on a different source spring; admission is free, but towels are not provided and the local etiquette of washing thoroughly before entering applies. Foot baths — the Yukemuri-tei pavilion is the best-known — line the promenade and are also free of charge.
Up the stone stairway on the north side stands Kosenji, the Buddhist temple from which Kusatsu Onsen takes part of its name. The hilltop view back down to the steaming basin is one of the classic perspectives of the town. About ten minutes' walk to the west, the Sai-no-Kawara Park opens out into a wider landscape of bubbling springs and a famous open-air pool. For an introduction to the geology and bathing customs of the region, the Goza-no-Yu bath complex on the east side combines historic architecture with two functioning bathhouses.
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Q&A
- Can you bathe in the Yubatake itself?
- No. The Yubatake is a working source and cooling field, not a bath. Its water is piped out to several nearby bathhouses, including Shirahata-no-Yu and Goza-no-Yu, which any visitor can enter for a small fee or for free.
- When is the best time of day to see it?
- Early morning offers the lightest crowds and the most visible steam. Twilight, when the lighting comes on but the sky is still bright, is the most photographed moment. In winter the contrast between cold air and rising vapor is most dramatic.
- Is the air around the Yubatake safe to breathe?
- Yes, under normal weather conditions. The sulfur smell is strong but the concentration in the open air is harmless to passing visitors. People with severe respiratory conditions may find the area uncomfortable for long stays.
- What is yu-no-hana and can you buy it?
- Yu-no-hana, literally "hot water flowers," is the pale sulfur sediment that forms when the spring water meets the air. It is harvested from the wooden conduits a few times a year, dried, and sold in small cylindrical packets in souvenir shops around the basin. A pinch added to a home bath imparts a fraction of the Kusatsu effect.
- How do you get to the Yubatake from Tokyo?
- JR Bus runs a direct service from Tokyo Station and Shinjuku to Kusatsu Onsen Bus Terminal in around four hours. By train, take the JR Tokaido Shinkansen or Joetsu Shinkansen route to Takasaki, transfer to the Agatsuma Line to Naganohara-Kusatsuguchi, and take a 25-minute bus on to the town. The Yubatake is five minutes' walk from the bus terminal.
Basic Information
| Name | Yubatake (湯畑) |
|---|---|
| Location | Oaza Kusatsu, Kusatsu-machi, Agatsuma-gun, Gunma Prefecture |
| Designation | National Place of Scenic Beauty (Meisho); designated 13 October 2017 by the Minister of Education, Culture, Sports, Science and Technology |
| Earlier honor | Selected among Japan's 100 Best Fragrant Landscapes (Ministry of the Environment, 2002) |
| Area | Approximately 1,112 m² within the stone fence |
| Source flow | About 4,040 liters per minute at approximately 52°C |
| Water character | Strongly acidic spring; pH approximately 2.0 |
| Conduits | Seven wooden yudoi, total length approximately 40 m |
| Stone enclosure | Designed in 1975 by the Institute of Contemporary Art under Taro Okamoto |
| Access (rail + bus) | JR Agatsuma Line to Naganohara-Kusatsuguchi, then JR Bus (about 25 min) to Kusatsu Onsen Bus Terminal; 5 min walk |
| Access (highway bus) | JR Bus from Tokyo Station or Shinjuku, approximately 4 hours |
| Viewing | Open at all hours; nighttime illumination until approximately 25:00 |
| Admission | Free |
References
- Yubatake | Kusatsu Town
- https://www.town.kusatsu.gunma.jp/www/contents/1485303527539/index.html
- About Cultural Properties of Kusatsu Onsen | Kusatsu Town
- https://www.town.kusatsu.gunma.jp/www/contents/1765842541149/index.html
- About Kusatsu Onsen | Kusatsu Town
- https://www.town.kusatsu.gunma.jp/www/contents/1485254967207/index.html
- Hot Spring Sources | Kusatsu Onsen Tourism Association
- https://www.kusatsu-onsen.ne.jp/onsen/source.php
- Designated Scenic Beauty "Yubatake" | Kusatsu Onsen Senshitsushugi
- https://www.yumomi.net/senshitsusyugi/gensen
- Yubatake | National Tourism Resource Database (Japan Tourism Bureau Foundation)
- https://tabi.jtb.or.jp/res/100144-
Last verified: 2026.05.17