Sulphate Springs: "The Healing Waters" — Indications for Bathing & Drinking

Asahidake Onsen was discovered in 1914, in a valley the Ainu called Yukomanbetsu, "the river that flows toward the hot water." Hotel Bear Monte, three minutes on foot from the Asahidake Ropeway base station, opened in 2003 and was renewed in 2022. Its clear sulfate water, once classed as a gypsum spring, is known locally as the "healing waters" for its gentle feel, and the large baths offer tubs at different temperatures for resting after hiking or skiing.

Ikaho is an ancient spa praised in the Man'yoshu poetry anthology. In the Warring States era its stone-step street was laid out as a healing retreat for soldiers wounded at Nagashino, and the koma-guchi system that divides the spring water among the inns survives today. Kogane-no-yu rises clear, but its iron oxidizes in the air and tints the water tea-brown, as its golden name suggests. This neutral water rich in sulfate and bicarbonate warms the body to the core and has long been called a spring for fertility. It is a bath that carries Ikaho's history itself.

Namegawa Onsen, one of the eight hot springs of Yonezawa, is a mountain healing retreat in the Azuma range said to have opened in the Edo period with permission from the Uesugi domain. The Uenoyu source gushes beside the Maekawa stream, its bluish milky-white water carrying a gentle scent of sulfur. The water feels weighty and smooth, leaving the skin soft and light after bathing. Deep in the mountains, it suits those who want a quiet soak to the sound of the gorge.

The Oyu source of Shimofuro Onsen carries a sulfur scent so strong that the place name is said to come from the Ainu word "shumafura," meaning "smelly rock." Recorded as "Yumoto" on a Muromachi-period map and bathed in by a Nanbu domain lord in 1656, this pH 2.4 acidic water turns milky as its sulfur flakes swirl, leaving a brisk, tightening touch and a lingering saline warmth. It suits those who wish to steep quietly in a strong sulfur spring within a port town that once thrived as a herring fishermen's spa.

This spring rises deep in the Azuma mountains at about 1,100 m, reached by a mountain road climbing beyond Shirabu Onsen from Yonezawa. Counted among Yonezawa's eight hot springs, it sits in a valley near the headwaters of the Mogami River, where bathers gaze at waterfalls and ridgelines from open-air pools. Rich in calcium, the water leaves white mineral flakes on the tub floor and feels soft and smooth, ideal for those who want to savor mountain scenery in secluded quiet.

Takanoyu rises by its own pressure from a drilled well on the northern foot of Mount Asama, right beside the Agatsuma Line, and travels about 80 meters by pipe to the baths. Its signature is balance: chloride, sulfate and bicarbonate dissolve in nearly equal measure, so one soak offers the warmth of a salt spring, the softness of a sulfate spring and the smoothness of a bicarbonate spring. Iron leaves brown deposits on the spouts and turns the water a cloudy green-brown on contact with air, a generous spring made for chilly highland nights.

Shibu Onsen, said to have been discovered by the monk Gyoki in the Nara period, is home to the No.1 Boring source, which gushes up on its own from a deep borehole at 97.6°C, close to boiling. Nearly clear and carrying a faint whiff of sulfur, the water wraps the body in salty, sulfate-rich warmth yet leaves a light, refreshed feeling afterwards. It suits travelers pausing between cobbled bathhouse visits and anyone seeking deep warmth on a cold mountain night.

This is one of the most well-known sources in Noboribetsu, a leading onsen destination in Hokkaido. It continuously flows at a high temperature of 96.5°C, embodying the raw power of the earth. The highly acidic water, with a pH of 2.2, provides a tingling sensation on the skin and a refreshing feeling after bathing. Its rich iron and sulfate content offers a powerful bathing experience that feels as if it's awakening both mind and body. It's a spring for those who wish to reset from daily fatigue, gain new vitality, and feel nature's energy throughout their entire being.

Originating from the fumaroles of Owakudani, born from the eruption of Hakone volcano approximately 3,000 years ago, this artificially developed hot spring began to be supplied to Sengokuhara and Gora by Hakone Onsen Kyokyu Co., Ltd. in Showa 5 (1930). Its renowned milky white waters, blended with naturally gushing spring water, offer a pleasant sensation that tightens the skin and a powerful restorative warmth that penetrates deep into the body's core. After bathing, you'll feel surprisingly refreshed and light. It's a perfect companion when you seek to feel the Earth's energy and achieve deep relaxation and rejuvenation for your mind and body.

Ikaho is an ancient spa praised in the Man'yoshu poetry anthology. In the Warring States era its stone-step street was laid out as a healing retreat for soldiers wounded at Nagashino, and the koma-guchi system that divides the spring water among the inns survives today. Kogane-no-yu rises clear, but its iron oxidizes in the air and tints the water tea-brown, as its golden name suggests. This neutral water rich in sulfate and bicarbonate warms the body to the core and has long been called a spring for fertility. It is a bath that carries Ikaho's history itself.

The Mandaiko source, originating from traces of past mining development, is deeply intertwined with Kusatsu Onsen's unique yumomi culture and its long history of toji (therapeutic bathing). Its highly acidic waters, among Japan's most potent, deliver a distinctive tingling sensation, awakening both mind and body and offering a sense of rejuvenation. The high-temperature blessings penetrate deep into the core, leaving you with a surprisingly light and refreshed feeling after your bath. We invite those seeking a genuine toji experience, a true escape from daily life to restore their mind and body, to discover the profound power of this spring.

National Source No. 2 of Bankei Onsen wells up along the Osaru River gorge in the Okutoya spa area, alongside neighboring Kitayuzawa Onsen. Reaching 82.7°C, this source reaches the tubs with only water added to adjust the temperature, and its minerals crystallize white around the spouts. The clear, light water warms the body to the core and leaves the skin smooth, suiting those who wish to steep quietly in a simple mountain bath to the sound of the river and birdsong.

Yamashiro Onsen, said to have been opened by the monk Gyoki some 1,300 years ago, draws this water from two wells: the No. 7 source gushing in Katsuradani-machi and the No. 8 source in Yamato-machi, blended at a relay tank in the town. The Yamashiro No. 7 and No. 8 blend is clear, gently alkaline and rich in sulfate, calcium and sodium, a soak whose warmth lingers long after bathing, well suited to travellers unwinding after a day among Kutani pottery studios.

The Yubatake source, naturally gushing from Kusatsu Onsen's iconic Yubatake (Kusatsu's central hot-water field), holds a distinguished history. During the Edo period, it was ranked as the highest-ranking Ozeki in the Onsen Banzuke, recognized alongside the Shirahata source as one of Kusatsu's two major hot springs. Its powerful, pH2 water, permeated with a sulfurous aroma, imparts a refreshing, tightening sensation upon the skin. A soak in this historic, renowned hot spring cleanses the body and mind, offering deep relaxation and rejuvenation from daily fatigue. It is a must-visit for those seeking to feel the energy of a historic hot spring and desire a complete refresh.

Ikaho is an ancient spa praised in the Man'yoshu poetry anthology. In the Warring States era its stone-step street was laid out as a healing retreat for soldiers wounded at Nagashino, and the koma-guchi system that divides the spring water among the inns survives today. Kogane-no-yu rises clear, but its iron oxidizes in the air and tints the water tea-brown, as its golden name suggests. This neutral water rich in sulfate and bicarbonate warms the body to the core and has long been called a spring for fertility. It is a bath that carries Ikaho's history itself.

Hakone Yumoto Onsen's history is said to date back to the Nara period, making it Hakone's oldest hot spring village. [2, 4] The Hakone no Yu Kamon source is a private spring drilled in this historic land. This sodium/calcium-chloride/sulfate spring follows in the tradition of famous waters once presented to the Shogun's family during the Edo period. [10] Its waters gently envelop the skin, providing a characteristic warmth that lingers long after bathing. It is recommended for those seeking to release mind and body in historic, nature-rich Hakone.

Kamioka Onsen flows on its own, without pumps, from a 170 m well drilled in 1957 in Beppu's Kannawa district. A 2025 analysis recorded 89.5°C and pH 9.0: an unusual alkaline sulfur spring in a town known for acidic sulfur waters, its sulfur dissolved as hydrosulfide ions rather than gas. Sodium 228.0 mg/kg, bicarbonate 279.0 mg/kg, sulfate 184.0 mg/kg and metasilicic acid 339.0 mg/kg give a clear water with a faint sulfur scent and a quiet, deeply comforting character.

Ikaho is an ancient spa praised in the Man'yoshu poetry anthology. In the Warring States era its stone-step street was laid out as a healing retreat for soldiers wounded at Nagashino, and the koma-guchi system that divides the spring water among the inns survives today. Kogane-no-yu rises clear, but its iron oxidizes in the air and tints the water tea-brown, as its golden name suggests. This neutral water rich in sulfate and bicarbonate warms the body to the core and has long been called a spring for fertility. It is a bath that carries Ikaho's history itself.

Shirahatage Genzen, located in Kusatsu Onsen and adjacent to Yubatake (Kusatsu's central hot-water field), is said to have been discovered by Minamoto no Yoritomo. Historically, it served as the stage for 'Jikan-yu' (timed bathing), supporting balneotherapy culture, and is truly considered the soul of Kusatsu. Its distinctive aroma and powerful waters, which feel as though they firm the skin, seem to awaken the mind and body from within. Surrendering to its embrace offers a pure moment to shed daily clamor and rediscover one's true self. This spring is a sanctuary for those seeking a fresh start and rejuvenation.

Nestled along the Tone River, Yujuku Onsen has been a beloved hot spring in a quiet post town, cherished by travelers and literati since the Edo period. Its waters, smooth as silk, envelop the skin in a veil of moisture, offering a truly silky skin experience. This restorative warmth penetrates deep into the body's core, gently releasing daily tensions and promoting deep relaxation. It is a renowned spring for those seeking rejuvenation and a peaceful recuperation amidst the tranquil mountain scenery, with its comforting warmth lingering long after bathing.

The Nuruyu source has been known since the Kyoho era (1716-1735), welling up at about 920 m on the eastern foot of Mt. Azuma-Kofuji. This acidic sulfate water carries iron and aluminum, emerging colorless and turning yellowish-white after a day. Though only 31.8°C, it lets warmth linger slowly in the body, leaving skin cool and smooth. It suits summer bathers and anyone who loves long, unhurried soaks in a water traditionally prized for the eyes.

Asahidake Onsen was discovered in 1914, in a valley the Ainu called Yukomanbetsu, "the river that flows toward the hot water." Hotel Bear Monte, three minutes on foot from the Asahidake Ropeway base station, opened in 2003 and was renewed in 2022. Its clear sulfate water, once classed as a gypsum spring, is known locally as the "healing waters" for its gentle feel, and the large baths offer tubs at different temperatures for resting after hiking or skiing.

This spring sits high in Kankaiji, one of Beppu's eight hot spring districts, and blends two sources through a mixing valve: the Sugi-2 well and a source at the Minamitateishi geothermal power plant, a very Beppu way of using the earth's heat for both power and bathing. Emerging at 91.4°C, its anions are 64 percent chloride and 21 percent sulfate with plenty of carbonate, giving a mildly alkaline water. Clear and faintly salty, its abundant metasilicic acid lends a soft, gentle feel.

Pumped from 1,000 meters beneath the Kuju Highlands in Aso-Kuju National Park, the Tenku no Daichi Kuju Kogen Hotel source is a true all-star spring, combining the properties of chloride, sulfate, and bicarbonate waters. Rich in metasilicic acid, a natural moisturizer, it leaves skin feeling smooth during the bath and wonderfully soft afterward. It's perfect for days when you want to deeply soothe body and soul while gazing at the majestic nature of the Kuju mountain range and Mount Aso.

The Yubatake source, naturally gushing from Kusatsu Onsen's iconic Yubatake (Kusatsu's central hot-water field), holds a distinguished history. During the Edo period, it was ranked as the highest-ranking Ozeki in the Onsen Banzuke, recognized alongside the Shirahata source as one of Kusatsu's two major hot springs. Its powerful, pH2 water, permeated with a sulfurous aroma, imparts a refreshing, tightening sensation upon the skin. A soak in this historic, renowned hot spring cleanses the body and mind, offering deep relaxation and rejuvenation from daily fatigue. It is a must-visit for those seeking to feel the energy of a historic hot spring and desire a complete refresh.

Kannawa has long been known as a healing retreat for the wounded, and this hillside source rises on its own as near-boiling 98.1°C water. Rich in sodium and calcium with a balance of chloride and sulfate, the faintly milky water leaves white, scale-like deposits along the tub edges. With 220.0 mg/kg of metasilicic acid, it leaves skin moist and soft, suiting anyone who wants to warm up slowly while gazing over Beppu's rising steam.

Esan Onsen Ryokan sits in Kashiwano, Hakodate, at the foot of the active volcano Mt. Esan, and keeps the air of a traditional healing inn. It is said to have begun when an earlier generation gathered the springs they found into a hand-dug basin, and today the naturally flowing source still pours from a single inlet into wooden tubs and over their edges. The water is nearly clear with a faint yellow-green tinge, a scent of iron and a sharp acidity, and white deposits form around the inlet. It is a strongly acidic sulfate spring rare in Hokkaido, and because the water is lukewarm the inn closes in winter.

This private spring in Nozawa Onsen first served a humble bathhouse for therapeutic stays in the Taisho era. Sulfate is its main component, joined by chloride, calcium and hydrosulfide, giving a mineral-rich water whose color shifts from lapis blue to milky white with the seasons and the hour. Because the freshly emerged water flows straight into the baths, it keeps its freshness. Long favored by guests seeking relief for cuts and bruises, it suits travelers who want to rest their bodies slowly and deeply.

The Shika no Yu source of Shikabe Onsen is said to have been discovered in the Kanbun era, when Ito Gengoro, who came from Tsugaru to harvest kelp, spotted a deer healing its wounds in the water. Once welling up naturally on the beach, this source still gushes at 77.5°C from beneath the fishing port. Its soft water, carrying a faint saltiness and a hint of the sea, wraps the skin and warms the body to the core, suiting travelers who wish to unwind slowly by Uchiura Bay.

Kaminoyu Onsen is a quiet spa in the hills beyond central Yakumo. Seiryuen's spring gushes naturally at 98°C and 60 liters per minute; because it is so hot, the water is tempered with added water, yet both indoor and outdoor baths are free-flowing. The salty water can turn faintly milky, and in the open-air bath a long hose is used to cool it on the way in.

Ishida Onsen's source flows naturally on the flanks of Mt. Esan, an active volcano, and is piped about 2.5 km down, inheriting the spring once used by a highland hotel. The 1984 analysis shows pH 2.1 and 5.518 g/kg of dissolved solids, with 2,972 mg/kg of sulfate plus abundant aluminum and iron, in the lineage of classic alum and green-vitriol springs. Clear at the source, the water oxidizes to a cloudy yellow-brown in the bath, with a squeaky feel, sour taste and metallic scent that speak of the volcano.

Shima Onsen is said to take its name from healing "forty thousand ailments," and this water blends two naturally flowing sources from its Yamaguchi district in a mixing tank. Sodium (about 59 percent) and calcium (about 38 percent) lead the cations, while chloride (64 percent) and sulfate (30 percent) dominate the anions. It pairs the warmth of salt with the moist softness of sulfate, clear and easy-going at a gentle 1.42 g/kg, a quietly embracing water beside the Shima River gorge.

The Irinoyu source rises in the mountains of Joshinetsu Kogen National Park near Usui Pass, at Kirizumi Onsen, a spa said to date back to the Kamakura period. In the Meiji era Kirizumi flourished as a summer retreat visited by statesmen and writers. About 300 liters a minute gush up naturally, and the lukewarm water, close to body temperature, lets fine bubbles linger on the skin. It suits anyone who wants to steep slowly in the quiet of the mountains and lose track of time.

The name Sakazuki is said to come from an Ainu word meaning ore. Hot water that welled up inside a wartime mine was piped around 1948 to an inn converted from a herring fishermen's lodge, the origin of Sakazuki Onsen. In 1962 wells were bored into the hot-water vein beneath the ore body: Well No. 1 at 221 m and Well No. 2 at 233 m. Well No. 2 is a gypsum-type spring led by sulfate with calcium and sodium, suited to anyone who wants a quiet, warming soak while gazing over the Sea of Japan and the fishing port.

In 1954, mineral flowers were found blooming on the banks of the Agano River, and a well was dug to open this comparatively young spa; the area's name was even changed to "Sakihana," meaning blooming flowers. Colorless when drawn, the water turns a clear yellow-green in the bath, leaving white mineral flakes on spouts and rails. A toasted, almost smoky sulfur aroma and a slick, weakly alkaline feel make it a favorite for sulfur-spring lovers.

This spring rises at a spa retreat about 900 m up the northwest flank of the Hakkoda Mountains, amid beech forest, in the area chosen as Japan's first National Health Resort Hot Spring. It has long filled a great bathhouse built entirely of hiba cypress alongside the area's other springs. At pH 1.71 it is strongly acidic, with a tingling bite on the skin and a faint scent of sulfur and iron; sinking into its milky water feels like the essence of a traditional healing spa, especially in deep-snow winter.

This unique created hot spring utilizes the fumaroles of Owakudani, which were formed by volcanic activity approximately 3000 years ago. In the early Showa period, Hakone Onsen Kyokyu Co., Ltd. developed this source to supply hot water to areas like Sengokuhara and Gora. The water, created by mixing volcanic gas and water, offers a distinct, tingling, and tightening sensation upon contact with the skin. The powerful energy from the earth delivers restorative warmth deep into the body, a warmth that lingers long after your bath. It is ideal for those seeking deep relaxation and rejuvenation, wishing to refresh their mind and body.

The Niseko-cho source is pump-lifted from the base of Niseko Annupuri International Ski Resort. Developed by the Hokkaido Chuo Bus Group, its colorless, clear waters are widely supplied to nearby hot spring facilities. Drawn from abundant natural forests, this spring offers a soft touch and provides restorative warmth, gently heating the body to its core. A subtle salt veil envelops the skin, leaving a lasting warmth that offers deep relaxation for bodies fatigued from outdoor activities. It is highly recommended for those seeking rejuvenation amidst grand nature.

Tsuta Onsen in southern Hakkoda has hosted bathers since the Heian period, when simple bathhouses already stood here. The Tsuta Onsen Shinyu source bubbles up directly beneath the baths, seeping through gaps in beechwood floorboards without ever touching the air. Its blend of sulfate and bicarbonate soothes the skin and lingers long after bathing, suiting travelers who pair a brief, hot soak with autumn walks around nearby Tsuta Pond.

Yugawara Onsen, sung of in the Man'yoshu as the water that "springs forth in the valley of Dohi in Ashigari," is one of Japan's oldest recorded hot springs. The Yugawara Onsen Mixed Source (Gongenyama Service Center) blends several of the town's wells into a single supply at 61.7°C and pipes it to inns across the resort. Its chloride and sulfate content gives a soft, enveloping feel, and warmth lingers on the skin long after bathing, suiting travelers who seek quiet recovery in the hills.