Poor Gastrointestinal Function & Onsen | Carbon Dioxide Springs Explained

Born in Fukuji Onsen, nestled in the mountains of Okuhida, where multiple sources merge into one. This special blend embodies the blessings of a land long cherished for its therapeutic waters. The soft, near-neutral water with a pH of 7.16 gently envelops the skin, while the high 95°C source delivers warmth to your core. This onsen is for those seeking to escape the everyday hustle, deeply relax their mind and body, and cherish themselves in a tranquil moment.

The Otome no Yu Source is pumped from a wooded corner of Matsushima in Sakura City, a short drive from Kitsuregawa Onsen, famed for its skin-beautifying waters. Gushing at over 400 litres per minute, the source carries a faint sulphur scent and a slippery, caressing feel. Its lukewarm water, close to body temperature, bubbles with fine foam at the inlet and lets tension melt away the longer it lingers on the skin. It suits those who shy away from hot baths and seek quiet, tree-shaded soaking.

Kidachi Onsen Yugashima No. 23 takes its name from a legend that Minamoto no Yoritomo, spotting steam among the rocks while hunting, pried them up with a wooden sword and released the water. Set beside the Kano River in literary Amagi-Yugashima, its calcium and sodium share the cations almost equally while sulfate and bicarbonate balance the anions. Clear, tasteless and odorless, it is a quiet, unassuming water.

This hot spring embodies the enduring passion of pioneers, delivered from Kuronagi Onsen in the upper reaches of the Kurobe River to Unazuki Onsen, approximately 7km downstream, after arduous wooden pipe laying construction in Taisho 12 (1923). Gushing at an abundant rate of approximately 2,000 liters per minute, its colorless and transparent waters seem to embody the pristine clarity of the gorge itself. With a soft touch that gently envelops the skin, it slowly warms the body to its core. Ideal for those seeking to unwind their mind and body, embraced by nature, at the various inns and public bathhouses throughout the town.

Gushing forth in the Yufuin Onsen area at the foot of Mt. Yufu, the Yufuin Yubel Hotel No. 1 Spring embodies the town's spirit. Yufuin, one of Japan's most famous hot spring resorts, has a history of avoiding boisterous development, instead cultivating a tranquil retreat where pastoral landscapes meet art. This alkaline simple spring, with its low-irritant properties, is a perfect expression of that philosophy. The soft, pH 8.5 water gently envelops the skin, leaving it feeling smooth and refreshed after bathing. It is a fine spring that offers a peaceful escape for those seeking to unwind both body and soul.

Sounkyo, the gorge of the Ishikari River, is one of Hokkaido's great mountain spa areas, fed by hot water from the volcanic Daisetsuzan range. Shingin no Yu was classified in a 2004 analysis as a simple spring with pH 6.4 and 0.514 g/kg of total components. Sodium and bicarbonate dominate, alongside 79.1 mg/kg of metasilicic acid and 80.8 mg/kg of free carbon dioxide. Gentle in composition yet carrying a faint sulfur scent, sometimes taking on a bluish tint in the bath, it is a quiet, smooth water much like the gorge itself.

Said to have soothed people since the Ainu era, Bankei's water once welled up naturally along the Osaru River. Today natural riverside springs and wells drilled in the Showa and Heisei eras are blended and piped by the town; the 70°C water is cooled to bathing heat, staying clear and soft on the skin.

Gushing in the renowned Yufuin Onsen region, the Nurukawa Onsen source is beloved for its tranquil setting despite being conveniently located near Lake Kinrin. This spring is characterized by its soft, clear, and gentle water, a classic simple onsen cherished by many facilities in Yufuin. Its weakly alkaline nature is mild on the skin, leaving you feeling refreshed yet deeply warmed after bathing. It's the perfect spring for days when you want to gently unwind both mind and body amidst the idyllic scenery of Mount Yufu.

Gero Onsen counts among Japan's three famous springs, and legend holds that when its waters once vanished, a white heron alighted on the Masuda riverbank to reveal a new gush. The Gero Onsen Soto pump station source draws on several centrally managed wells and sends them on to inns throughout the hot-spring town. Its pH 8.9 alkaline water glides softly over the skin and lingers as a light, refreshed feeling, soothing travelers who stroll the hot-spring town and seek gentle rest.

The Sanso Tensui source is a private spring nestled in the mountains of Amagase Onsen, one of Oita's three great hot springs alongside Beppu and Yufuin. Established in 1995 on a vast 10,000-tsubo (approx. 33,000 m²) estate overlooking the famous Sakurataki Falls, this relatively new source gushes forth pure, heavenly water. The high-temperature 64.5°C spring water is used free-flowing with added cool water, known for its gentle, smooth touch on the skin. Surrounded by the murmur of a clear stream and lush greenery, it offers deep healing and tranquility to those wishing to escape the city's hustle and bustle.

Nestled within the grounds of Suzuka Circuit, one of the world's premier racing courses, this unique hot spring has offered a soothing retreat to race fans and families since its 1994 opening. Its weakly alkaline waters, drawn from underground, are gentle on the skin with minimal irritation, effortlessly permeating the body. Ideal for cooling race excitement and gently refreshing an uplifted mind and body, this spring continues its legacy of healing in a renewed form since 2023, providing tranquility to all visitors.

Gero Onsen counts among Japan's three famous springs, and legend holds that when its waters once vanished, a white heron alighted on the Masuda riverbank to reveal a new gush. The Gero Onsen Soto pump station source draws on several centrally managed wells and sends them on to inns throughout the hot-spring town. Its pH 8.9 alkaline water glides softly over the skin and lingers as a light, refreshed feeling, soothing travelers who stroll the hot-spring town and seek gentle rest.

Akanko Onsen spreads along the south shore of Lake Akan, home of the marimo moss balls, and is one of eastern Hokkaido's leading spa towns. This water is pumped from a well in the lakeside district that once also fed a public bathhouse for local residents. It is a mild simple spring, yet bicarbonate and metasilicic acid give it a smooth touch, and its clear water with a faint iron note gently loosens a body chilled by walks around the lake and forest.

Kumanotearaiyu Gensen takes its name from a legend of a wounded bear, fleeing hunters, that soothed its injuries in these waters, and it is regarded as the birthplace of Nozawa Onsen. Said to have been opened in the Kamakura period, the spring still gushes naturally at 251 liters per minute. Its clear water carries a faint sulfur scent and leaves the skin smooth, with a light, refreshed feeling that lingers after bathing — a fitting soak for travelers tracing the roots of Nozawa's bathing culture.

Nestled in the scenic town of Matsuyama, this spring has long been cherished for relieving traveler fatigue, boasting robust eagle-like properties. The hypertonic chloride waters envelop the skin, smoothly expelling excess fluids and metabolic waste. The lightness after bathing and deep-penetrating warmth soothe the mind and body, freeing you from daily stress. Ideal for those with chronic stiffness or cold extremities, and perfect for weekend rejuvenation.

This ANA InterContinental Beppu Resort & Spa Tsuboyu Gensen source was developed using modern drilling techniques on a highland overlooking the historic, steam-filled streets of Kannawa, Beppu, a renowned therapeutic bathing area since the Kamakura period. A key feature is the dissolved salt, which gently envelops the skin to provide long-lasting warmth after bathing. It offers a moment of deep release for those seeking to connect with Beppu's magnificent nature.

The Shiroyu source is one of four springs of differing character that rise within about 50 meters of one another at Yunotai, said to be the oldest bathing ground of Nyuto Onsen, where records of a spa date back to the Edo period. Long called the "beauty spring" and the "spring for chills," it bubbles up beneath an open-air bath and is also piped to nearby lodgings. Its bluish, cloudy water carries a gentle sulfur scent and a soft, smooth touch, leaving skin supple and warmth that lingers long after a soak, a spring for anyone who wants to unwind slowly in the beech forest.

Local lore says this spring was found in 1972 after a divine revelation, a story preserved in its name. Pumped from deep beneath a hillside facing Mt. Fuji and the Kofu Basin, the sodium chloride water is mildly alkaline and smooth, with a faint brown tint and a hint of sulfur, combining lasting warmth with a gentle feel on the skin.

The Kowakien Kyokyu Onsen is a steam-generated spring developed since 1949 to supply the Hakone Kowakien resort area. It utilizes geothermal heat from former fumarolic activity along the Kurumazawa stream, a tributary of the Jakotsu River, blending multiple sources and natural spring water. This source is widely distributed to the various facilities of the Hakone Kowakien resort, operated by Fujita Kanko, forming the foundation of the entire resort.

Kinosaki Onsen's centrally managed mixed spring gathers water from several wells into a large storage tank, where its temperature is steadied before it flows through a looped pipe beneath the streets to the town's public bathhouses and inns. Managed as a shared resource by the Yushima property ward of Kinosaki, this faintly salty water wraps the body in warmth that lingers long after bathing, suiting travellers who stroll from bath to bath in yukata.

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.

Hot springs in Shinshinotsu began with the No.1 well drilled in 1990, whose water had to be heated. In 2015 the No.3 well, reaching 1,600 m, was completed, delivering water above 50°C ready to use. Rising beneath the Ishikari Plain beside oxbow Lake Shinotsu, it is a yellowish-brown, intensely salty water with a faint medicinal note from iodine and bromine. Its dense salts wrap the skin and keep you warm long after bathing, a fine companion for harsh winters.

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.

Kinosaki Onsen's centrally managed mixed spring gathers water from several wells into a large storage tank, where its temperature is steadied before it flows through a looped pipe beneath the streets to the town's public bathhouses and inns. Managed as a shared resource by the Yushima property ward of Kinosaki, this faintly salty water wraps the body in warmth that lingers long after bathing, suiting travellers who stroll from bath to bath in yukata.

A new 'Wa-modern' current emerged in Noboribetsu Onsen's history in 2006. This distinctive spring, with its faintly fragrant sulfur, evokes a sense of travel, while its chloride and sulfate composition gently infuses the skin with rich warmth. The heat gradually permeates the body's core, offering a pleasant restorative warmth that endures post-bath. It is perfectly suited for those desiring deep relaxation for mind and body in a sophisticated ambiance, far from daily clamor.

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.

Kinosaki Onsen's centrally managed mixed spring gathers water from several wells into a large storage tank, where its temperature is steadied before it flows through a looped pipe beneath the streets to the town's public bathhouses and inns. Managed as a shared resource by the Yushima property ward of Kinosaki, this faintly salty water wraps the body in warmth that lingers long after bathing, suiting travellers who stroll from bath to bath in yukata.

Lake Shikaribetsu, at about 800 m, is Hokkaido's highest natural lake. Hot-spring rights on its shore changed hands in the 1920s and an inn opened in 1931; natural outflows were used until around 1965, after which water was drawn from drilled wells. Clear at the source, it turns a cloudy yellow-green in the tub and stains the floor brown with mineral deposits. A faint sulfur scent, an iron-tinged carbonate taste and a smooth, slippery feel mark the water, and in winter an ice-top open-air bath appears on the frozen lake.

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.

This blessed spring gushes from 250 meters beneath the natural splendor of Oku-Hida. The water, a blend of abundant bicarbonate ions and metasilicic acid, feels silky smooth on the skin and has long been cherished as a 'beauty spring.' After bathing, you'll notice your skin feeling moist and smooth, with a warmth that lingers from your core. This spring is a gentle companion for those seeking a moment of peace to unwind both mind and body from the hustle and bustle of daily life.

The spring began in 1975, when a local farmer bored for hot water to warm his greenhouses and his own bath. Redrilled in 1999 to about 1,520 m, Well No. 2 now yields 73.6°C water: nearly colorless and clear, yet unmistakably salty, a dense sodium- and calcium-bearing chloride spring with a plain, sturdy character.

Named after the warlord Uesugi Kagetora, who met his end at Samegao Castle, the Kagetora no Yu source was drilled in 2017 in the hills of Jinguji, Myoko, below the castle ruins. Piped from the slopes at about 39°C, its dense salty water steeps into the skin and lets warmth linger long after bathing, while iron stains the rocks reddish brown. It suits travelers tracing Sengoku-era history who want to warm up to the core on chilly days.

Housen-no-Yu, a precious spring at Kusatsu Onsen, one of Japan's three most famous hot springs, has naturally gushed from bedrock for approximately 1200 years. Distinct from major sources like Yubatake and Bandaiko, this rare water gently envelops the skin with its sulfurous aroma. Its crisp quality offers a sensation of purifying both mind and body. After bathing, your skin will feel wonderfully silky, and the restorative warmth from deep within will invite deep relaxation, supporting overall rejuvenation. It is highly recommended for those seeking to escape daily life and reset themselves with a truly special hot spring experience.

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.

Dake Onsen's association source feeds a spa village said to have opened in 1674. Its self-flowing water is piped several kilometers down from the slopes of Mt. Iwaki, and the local association flushes sulfur deposits from the pipes every month. Listed in Edo-period hot spring rankings, its sharply sour, sulfurous water suits travelers seeking an old-fashioned toji retreat.

The Koganezaki Furofushi Onsen source gushed up in 1970 when a well was bored 200 meters beneath the shore of Koganezaki, and its name expresses the wish that those who rest here will neither age nor weaken. Clear at the moment it emerges, the water oxidizes into a rust-red hue as its iron meets the air, while its dense salts wrap the body and let warmth linger deep inside. It soothes travelers who want to unwind slowly while the sun sinks into the Sea of Japan.

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.

Yugawara Onsen is an ancient spa sung of in the Man'yoshu poetry anthology, and Oku-Yugawara, its innermost reach, is a quiet retreat wrapped in the Fujiki River gorge and deep greenery. Yugawara No.77 is a private source here, a calcium sulfate spring once called a gypsum spring. Its main components are 939.0 mg/kg of sulfate and 398.0 mg/kg of calcium; the water is clear and mild in taste and smell, yet carries a faint toasty note typical of sulfate springs. Soft and weakly alkaline, it clings gently to the skin and has long been valued for soothing cuts and skin troubles, suiting bathers who want a calm soak amid the greenery.

Nakabusa Onsen is a lone mountain inn in the Northern Alps, where legend says the general Sakanoue no Tamuramaro healed his wounded soldiers; a bathhouse opened here in 1821 alongside alum mining. With nearly 30 naturally flowing sources, each tub offers a different spring. This mixed spring feeds the Oyu bath, combining Mushiburo No. 1 and Konabetate and cooling the water by heat exchange and air rather than adding water. The alkaline water is silky enough to make the floor slippery, with a faint sulfur scent and valley views from the open-air tub.

Rising in a district long known by the place name "Yuden", this spring was developed in 1952. It emerges at 20.7°C as a cold mineral spring whose defining trait is a trace of dissolved radon. With only 0.185 g/kg of dissolved solids, the water is light and unassuming, like a quiet companion for unhurried, restorative bathing.