--- title: "Kusatsu Onsen: the hot-spring town around the Yubatake" description: "Kusatsu Onsen in Gunma stands 1,200 meters up on the slope of a volcano. At its center is the Yubatake, a spring that sends 4,000 liters a minute down wooden troughs." url: https://kama-meshi.com/en/articles/kusatsu-onsen language: en published: 2026-11-11 category: "Places in Japan › Gunma" tags: ["Gunma", "Onsen"] author: "Oginoya Editorial Team" publisher: "Oginoya Co., Ltd." translations: zh-TW: https://kama-meshi.com/zh-tw/articles/kusatsu-onsen ko: https://kama-meshi.com/ko/articles/kusatsu-onsen zh-CN: https://kama-meshi.com/zh-cn/articles/kusatsu-onsen zh-HK: https://kama-meshi.com/zh-hk/articles/kusatsu-onsen th: https://kama-meshi.com/th/articles/kusatsu-onsen de: https://kama-meshi.com/de/articles/kusatsu-onsen fr: https://kama-meshi.com/fr/articles/kusatsu-onsen es: https://kama-meshi.com/es/articles/kusatsu-onsen --- # Kusatsu Onsen: the hot-spring town around the Yubatake ![A pool of pale green hot-spring water edged with dark rocks, rows of wooden troughs beyond it, and inns along the street behind](https://kama-meshi.com/_astro/kusatsu-yubatake-2017.FTYVinpG_2ums1o.webp) Kusatsu Onsen is a hot-spring town in northwestern Gunma Prefecture, on a plateau about 1,200 meters above sea level on the eastern slope of the volcano Mount Kusatsu-Shirane, where strongly acidic water rises unpumped at more than 32,300 liters a minute. At the center of the town is the Yubatake, the "hot-water field": a spring where about 4,000 liters a minute well up, run down seven wooden troughs to cool, and fall over bare rock as a waterfall. ## Water that dissolves a nail Every spring in Kusatsu flows out of the ground on its own, and the total is counted as the largest natural outflow of any hot-spring resort in Japan. The water is thought to begin as rain on the eastern slope of Mount Kusatsu-Shirane, an active volcano 2,160 meters high. The rain seeps underground and meets hot gas and hot water. The water has a pH of about 2.0, and 2.1 at the Yubatake. A nail 15 centimeters long left in the Yukawa, the stream that runs through Kusatsu, dissolves in about ten days. Of Kusatsu's six main springs, Bandai rises at about 94.5°C and the other five, the Yubatake among them, at around 50°C. ## The Yubatake The troughs of the Yubatake, called *yudoi*, were installed between 1887 and 1896. There are seven, each about 40 meters long and made of red pine. The troughs are thought to have been put in to cool the water, to let hydrogen sulfide escape and to collect *yunohana* ("flowers of the hot water"), the minerals that settle out of the water. Because the water cools in the open air as it runs down the troughs, it is used without being diluted. Water from the Yubatake is piped to more than 80 inns and bathhouses in the town. The present stone fence around the Yubatake dates from 1975 and was designed by an institute headed by Okamoto Tarō, the artist who made the Tower of the Sun for the Osaka Expo. The eighth Tokugawa shogun, Yoshimune, had water from the Yubatake carried to Edo Castle, and the frame that marks where the water was drawn remains in the Yubatake. On October 13, 2017, the Yubatake was designated a national Place of Scenic Beauty. ## Visitors since the fifteenth century Legend credits the discovery of the springs to the prince Yamato Takeru, to the monk Gyōki, or to Minamoto no Yoritomo, founder of the Kamakura shogunate, during a hunt in 1193. Written records begin in the second half of the fifteenth century. In 1491 the monk Banri Shūku wrote that the finest hot springs in the country were Kusatsu, Arima and Yushima, the present Gero. Kusatsu, Arima and Gero are called Japan's three famous hot springs. In the age of the warring states many warlords came to Kusatsu for a cure, and Maeda Toshiie bathed there in 1598. Between 1804 and 1830 more than 10,000 bathers arrived each year. A ranking of the country's hot springs printed in 1817, laid out like a sumo ranking sheet, placed Kusatsu as *ōzeki* of the east, and ōzeki was the highest rank at the time. ![A sheet printed in black, laid out in columns like a sumo ranking, with 諸國温泉功能鑑 across the top and 上州草津の湯 at the head of the right-hand column](https://kama-meshi.com/_astro/onsen-banzuke-shokoku-onsen-kounou-kan.DXQKepT6_Zr7EKr.webp "A ranking of hot springs in an edition of 1851. Kusatsu heads the right-hand column, the east.") ## Yumomi and the timed bath Most of Kusatsu's springs are too hot to step into, and adding cold water would thin the spring water. Bathers instead stirred the bath with wooden boards about 180 centimeters long until the water cooled. This stirring is *yumomi*. ![Long wooden boards with くさつ written on them, laid in rows across the wooden rims of two baths](https://kama-meshi.com/_astro/kusatsu-yumomi-boards-2019.BO1_7MmT_Z23kfGQ.webp "Yumomi boards at the bathhouse Netsu-no-yu, 2019.") Around 1877 the way of bathing was fixed as *jikan-yu*, the timed bath. On the orders of a bath master, the bathers stirred the water, poured more than 30 ladles of hot water over their heads, went into the bath together for three minutes and came out together, four times a day. At the bathhouse Netsu-no-yu the timed bath continued until 1957, and in 1960 yumomi began to be performed there as a show for visitors. The bathers sang to keep time as they stirred. The song that spread across Japan is "Kusatsu-bushi," with its refrain "choina choina" and its opening line, "Kusatsu yoi toko, ichido wa oide": Kusatsu is a fine place, come at least once. "Kusatsu-bushi" was sung in Kusatsu from about 1918 and became popular nationwide from about 1923. The town maintains 19 communal bathhouses and opens some of them free of charge to visitors as well as residents. ![A wooden bathhouse with snow on its tiled roofs and a board reading 白旗乃湯 over the entrance](https://kama-meshi.com/_astro/kusatsu-shirahata-no-yu-2019.nOR0HygV_21OBuY.webp "The communal bathhouse Shirahata-no-yu, in front of the Yubatake, 2019.") ## Erwin von Bälz Erwin von Bälz (1849–1913), a German physician, came to Japan in 1876 to teach at the Tokyo Medical School, later the medical faculty of the University of Tokyo, and taught until 1902. He first visited Kusatsu in 1878, returned several times and analyzed the water. Bälz wrote in his diary that Kusatsu had, besides hot springs without equal, the finest mountains and air in Japan and ideal drinking water. He made Kusatsu known abroad, and the town calls Bälz its benefactor. ## Winter at 1,200 meters The average temperature over the year in Kusatsu is 7°C. July and August average 18°C, and the temperature seldom passes 30°C. In winter northwest winds bring snow to the ski slopes. In earlier centuries the inns closed from October 9 to April 7 and everyone moved down to lower villages for the winter, a custom called *fuyuzumi*, "winter living," that lasted until the middle of the Meiji era (1868–1912). ## A town without a railway No railway reaches Kusatsu. Buses run to the town from Naganohara-Kusatsuguchi Station on the JR Agatsuma Line, in the neighboring town of Naganohara. From 1926 a railway joined Kusatsu to [Karuizawa](https://kama-meshi.com/en/articles/karuizawa-history), the summer resort across the prefectural border in Nagano. It opened as the Kusatsu Light Railway, whose first section, about 10 kilometers from Shin-Karuizawa, began running in July 1915. The line reached Kusatsu in 1926, 55.5 kilometers from Shin-Karuizawa, and it is remembered by its later name, the Kusakaru Electric Railway. In April 1946 the national railway began carrying passengers to Naganohara, and the Kusakaru line's passengers began to fall. The section from Shin-Karuizawa to Jōshū-Mihara closed on April 25, 1960, and the remaining section into Kusatsu on January 31, 1962. Karuizawa stands just west of the Usui Pass, and trains from Tokyo reached it by [the railway that opened in 1893](https://kama-meshi.com/en/articles/yokokawa-usui) from Yokokawa, on the Gunma side of the pass. Yokokawa is the station where [Tōge no Kamameshi](https://kama-meshi.com/en/articles/what-is-kamameshi), the ekiben (station bento) in a clay pot, went on sale in February 1958. ## References - [Town of Kusatsu, "About Kusatsu Onsen"](https://www.town.kusatsu.gunma.jp/s013/040/020/1485254967207/index.html) - [Town of Kusatsu, "Yubatake"](https://www.town.kusatsu.gunma.jp/s002/040/020/1485303527539/index.html) - [Town of Kusatsu, "Bälz Memorial Hall"](https://www.town.kusatsu.gunma.jp/s002/040/010/1485310375253/index.html) - [Agency for Cultural Affairs, database of nationally designated cultural properties, "Yubatake"](https://kunishitei.bunka.go.jp/heritage/detail/401/00004000) - [Kusatsu Onsen Tourism Association, "Kusatsu Onsen, a renowned hot spring"](https://www.kusatsu-onsen.ne.jp/onsen/) - [Kusatsu Onsen Tourism Association, "The springs"](https://www.kusatsu-onsen.ne.jp/onsen/source.php) - [Kusatsu Onsen Tourism Association, "Netsu-no-yu: the history of yumomi"](https://www.kusatsu-onsen.ne.jp/netsunoyu/history.html) - [Kusatsu Onsen Tourism Association, "About Kusatsu: climate"](https://www.kusatsu-onsen.ne.jp/youkoso/iroha01.php) - [Kusatsu Onsen Tourism Association, "About Kusatsu: history"](https://www.kusatsu-onsen.ne.jp/youkoso/bunka03.php) - [Kusatsu Onsen Tourism Association, "About Kusatsu: culture"](https://www.kusatsu-onsen.ne.jp/youkoso/bunka02.php) - [Kusakaru Kōtsū, "Kusakaru Electric Railway web museum: history"](https://www.kkkg.co.jp/museum/history.html) - [Kotobank, "Kusatsu Onsen"](https://kotobank.jp/word/%E8%8D%89%E6%B4%A5%E6%B8%A9%E6%B3%89-55117) - [Kotobank, "Kusatsu-bushi"](https://kotobank.jp/word/%E8%8D%89%E6%B4%A5%E7%AF%80-483096) - [Kotobank, "Bälz"](https://kotobank.jp/word/%E3%81%B9%E3%82%8B%E3%81%A4-3169327) Image credits (resized for display): - [くろふね / Wikimedia Commons](https://commons.wikimedia.org/wiki/File:%E8%8D%89%E6%B4%A5%E6%B8%A9%E6%B3%89%E3%81%AE%E6%B9%AF%E7%95%9101.jpg), [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0), 2017 - [Unknown (Edo-period print; uploaded to Commons by Namazu-tron) / Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Shokoku_Onsen_Kounou_Kan.jpg), Public domain, 1851 - [Σ64 / Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Kusatsu_Yumomi,_Gunma_01.jpg), [CC BY 4.0](https://creativecommons.org/licenses/by/4.0), 2019 - [Quatrogatos / Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Kusatsuhotspring_shirahatanoyu.jpg), [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0), 2019