Hot Spring Therapy for Mild Hypertension | All 10 Types & the Special Role of CO₂ Springs

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.

Once a desolate area called "Lesser Hell," this land was renamed Kowakidani following a visit by Emperor Meiji, sparking its development as a hot spring resort. This combined source is one of several springs utilized in this historic onsen town. Developed by entrepreneurs in the Meiji era, the area saw the construction of numerous inns and villas. This very source has supplied water to accommodations throughout the Kowakidani area, laying the foundation for Hakone's modern onsen culture.

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.

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.

Murata Onsen is a pumped, drilled source in Kawakami, part of Yufuin, a spa town famed for its abundant springs. It emerges at a hot 63.9°C, and the clear, faintly yellow-brown water carries small dark-brown mineral flakes. Though mild as a simple spring, it is rich in metasilicic acid at 189.0 mg/kg, leaving a soft, clinging feel on the skin—ideal for unhurried soaks in the quiet hills.

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.

Analyzed in 2020, this is a relatively new spring on the shore of Tara, where the slopes of Mount Tara run down to the Ariake Sea. It emerges as a cool 22.8°C mineral spring; bicarbonate makes up about 80 percent of the anions, while magnesium, calcium and sodium share the cations almost evenly. At just 0.18 g/kg it is soft, almost like fresh water, yet 69.5 mg/kg of metasilicic acid gives it its character as an onsen, a quiet water to sink into while watching the great tides of the Ariake Sea.

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.

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.

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.

Drilled beside the Otaru Canal, lined with Meiji-era stone warehouses, this source is pumped up at 330 liters per minute. Though it emerges as a 20.5°C cold mineral spring, its chloride-rich water, once warmed, wraps the skin softly and lets warmth linger long after the bath. It suits travelers who want to steep away the chill after strolling the canal-side streets.

Nestled quietly in the mountainous region of Toyama Prefecture, Ogawa Onsen gushes forth. This naturally gushing spring, cherished by locals for generations, delivers the pure blessings of the earth. Its mild, neutral waters gently embrace the body, while a subtle veil of salt ensures a restorative warmth that lingers. Guests will also experience the benefit of silky skin, feeling remarkably light and refreshed after their soak. It is highly recommended for those seeking deep relaxation from daily fatigue, and those desiring gentle comfort for cold sensitivity or gastrointestinal discomfort.

Hirayu Onsen, nestled deep within Okuhida Onsenkyo and embraced by the Hida Mountains, is an ancient hot spring said to have been discovered by Takeda Shingen's defeated warriors. Its waters, rich in chloride and bicarbonate springs, gently refine the skin, promoting a silky skin sensation, while delivering restorative warmth deep into the body. This pleasant warmth lingers long after your bath, feeling like a blessing from the mountains. It is highly recommended for those seeking deep relaxation and a respite from daily life while admiring the Northern Alps, or for hikers wishing to soothe their weary bodies.

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.

Misasa Onsen is said to have been discovered some 850 years ago when a samurai who spared a white wolf was guided to the spring in a dream, and its name is linked to the belief that "by the third morning, ailments are healed." It is known for radium springs with some of the world's highest radon levels. Rakusen wells up naturally from the ground along the Mitoku River, and hot water rises constantly from the spring pocket at the bottom of the tub.

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.

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.

This specific spring, pump-lifted from the underground of Higashi 3-chome in Jozankei Onsen—Sapporo's tranquil retreat—has been affectionately known since ancient times as 'Atsu no Yu,' or the 'Hot Water Spring.' Its unique salt components form a delicate veil on the skin, providing a restorative warmth that gently permeates the body's core. The comforting heat continues long after your bath, aiding in deep relaxation and relieving daily tension. It's a soothing haven for those wishing to escape urban hustle and achieve a profound sense of rejuvenation.

Ginzan Onsen is said to trace its origins to waters found by miners of the Nobesawa silver mine, which flourished in the Edo period, and the town still carries the mine's name. This blend of cooperative sources No. 2, 3 and 6 rises at 63.8°C, layering sodium and chloride with sulfate, and white mineral flakes drift softly through it. Rich in metaboric and metasilicic acid, it leaves the skin moist and the body warm long after bathing, suiting those who want to warm to the core in a riverside town lit by gas lamps on snowy nights.

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.

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.

Togatta Onsen is said to date back to the early Edo period, growing along the Matsukawa River that flows from the Zao range. This high-temperature well holds 296.0 mg of sodium, with bicarbonate (320.3 mg), sulfate (224.5 mg) and chloride (196.9 mg) in nearly equal shares. With 117.2 mg of metasilicic acid it feels silky on the skin. Wrapped in brown mineral flakes, it is like a quiet, wise elder of the forest.

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.

Nukabira Gensenkyo began in the Taisho era when water hot enough to boil eggs was found deep in a primeval forest; the name is said to come from the Ainu word "Nukabira," a cliff shaped like a person. Kosenchi No. 1 flows naturally in the south district of the spa village, sustaining the free-flowing baths that the village's inns pledged together in their 2007 "Gensen Kakenagashi Declaration." Clear and nearly tasteless and odorless, the water is gentle on the skin and leaves a light, fresh feeling, suiting those who want to soak amid forest stillness, wild deer and starry skies.

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.

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.

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.

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.

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.

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.

Nestled in the Hakone Yumoto area, Yumoto Onsen (a blend of sources No. 12, 72, 84, 89, 99, and 112) is a luxurious fusion of six distinct springs. It symbolizes the abundant water volume of Yumoto, which historically thrived as one of the ancient Hakone Seven Hot Springs. The chloride spring water, enveloping the skin like a delicate veil, delivers restorative warmth deep into the body's core. The lingering, cozy sensation after bathing gently promotes deep relaxation, easing away daily fatigue. This spring is recommended for those seeking to deeply warm their body and mind and indulge in tranquil moments.

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.

Said to date back to the Heian period and linked to the monk Gyoki, this sacred spring once welcomed pilgrims bound for Kumano. Its natural flow ceased for centuries until a 1965 boring struck water at 501 m, and today its calcium- and magnesium-rich water builds thick mineral crusts around every bath.

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.

Drawn from 700 meters beneath the center of Oita City, this private source is a true urban oasis. The Ariston Hotel Oita source boasts a pH of 8.6 and abundant bicarbonate ions, which gently exfoliate the skin, leaving it remarkably smooth. Its amber-hued waters invite deep relaxation, melting away the day's fatigue. It is perfect for those seeking to refresh and rejuvenate after a day of business or sightseeing.

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.

Said to have opened in 1720, Shinyu Onsen is one of the Kurikoma Five Springs on the upper Sanhasama River and was long called a "phantom spring." Its dormant source was revived in 2006 and again soothes mountain hikers. Clear and cool as it emerges, the water turns milky with a sulfur scent once warmed, filling the tub with fine white flakes, a source for those who enjoy watching a spring transform in mountain quiet.

Sarugawa Onsen has long been known as a cold spring seeping naturally from the left bank of the Saru River in a national forest, with piping to the baths beginning in 1973. As the natural flow dwindled, an 80-meter well was drilled in 1997 and now feeds the baths. The pH 9.4 alkaline water carries a faint hint of sulfur and leaves skin feeling smooth, suiting skiers and campers who want to unwind in the Hidaka hills.

Kurume Onsen rises in Yunosaka, on the eastern edge of Kurume overlooking the Chikugo Plain, where drilling in the late Showa era struck a spring that flows by its own pressure. It still gushes 94 liters a minute at over 50°C without pumps. The alkaline water carries a faint scent of sulfur and leaves a squeaky-clean, smooth feel, an unpretentious beauty bath right on the city's doorstep.

Tengu no Yu gushes naturally in the mountain hollow of Doroyu Onsen, a spa said to have opened in the early Heian period. Its name comes from a legend: a sick maiden too shy to bathe in clear water was helped by a tengu who clouded the spring white, and she was healed after soaking in it. The Tengu no Yu source swirls with white mineral flakes and mud-like sediment, leaving the skin feeling soft and supple, a steeping place for anyone who loves cloudy, remote hot springs.