Rheumatoid Arthritis & Onsen | Radon Springs and the General Bathing Indication

Hakone-Yumoto Onsen, said to have opened in the Nara period, boasts the oldest history in Hakone. This Yumoto No. 29 & 46 Goko-sen is a blend of multiple sources from this historic spa town. It is used in public bathhouses along the old Tokaido road, having soothed weary travelers for centuries.

This Radon-sen No. 1 source plays a key role as one of the "Ginsen" (Silver Springs) that color the history of Arima Onsen, one of Japan's three ancient hot springs. In contrast to the reddish-brown "Kinsen" containing iron, Ginsen is characterized by its clear, smooth feel. The water from this source is said to gently stimulate cells and vitalize the body as it's absorbed through breathing.

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.

This is one of the private sources gushing in Yufuin Onsen, one of Japan's most popular hot spring resorts. The "On-yu" source is a simple hot spring drawn from within the property, known for being gentle and suitable for everyone due to its low mineral content. Its weak alkalinity of pH 8.2 gently removes dead skin cells, leaving the skin feeling smooth. Rich in metasilicic acid, a natural moisturizing component, it helps hydrate the skin after bathing. This spring is recommended for those seeking a gentle bath to unwind both body and soul while surrounded by the majestic nature of Mount Yufu.

Okudogo No. 4-1 Gensen is drawn from the gorge upstream along the Ishite River from Dogo's historic spa town. Its lukewarm 38.7°C water is alkaline at pH 9.4 and pairs hydrosulfide ions with radon, an uncommon combination. A faint sulfur scent and slippery feel suit bathers who like long, unhurried soaks to the sound of the stream.

This spring began welcoming bathers in 1964, when the Yamanami Highway opened, on a rise at the center of Kurokawa Onsen. Though light in dissolved minerals, its weakly acidic water at pH 3.7 carries iron, releasing a faint sulfur and metallic note from nearly clear water. It suits travelers who stroll the mountain hot-spring village and want a refreshing soak between baths.

Hirugami's waters famously burst forth in 1973 during railway tunnel construction. Wells No. 2 to 5 followed, and today their blended "new mixed spring" is centrally managed and piped to the inns of the valley. At pH 9.8 it is strongly alkaline, giving the skin a slippery, silky feel, with a faint sulfur scent and gentle sweetness.

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.

Yakumo Onsen lies in forested hills along the Namarikawa River on the Oshima Peninsula. Water from Namarikawa Well No. 3 is rich in bicarbonate and chloride and carries over 410 mg/kg of free carbon dioxide. It carries a faint scent of iron and is concentrated enough for mineral crystals to float on the surface. Slightly salty, it warms the body to the core while leaving the skin moist and smooth, suiting those who want a long, unhurried soak in mineral-rich water to the sound of the river.

Biratori has bathed in cold mineral water since 1979, first trucking in water that seeped naturally across the river. In 2011 a 1,503 m borehole was sunk at Nibutani on the Saru River, a place that still carries Ainu culture, and tapped a new cold spring. At 12.1°C and a mildly alkaline pH 8.3, it holds 22.06 g/kg of minerals, led by 6,303 mg of sodium, 2,016 mg of calcium and 13,400 mg of chloride, close to seawater in strength. Clear, colorless and intensely salty, it feels like ancient sea water sleeping deep beneath Hokkaido.

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.

Motonoyu is the shared source of Hanashiki Onsen, welling up beside the confluence of the Shirasuna and Nagasasazawa rivers and managed by the local Iriyama Hanashiki property association. Legend says Minamoto no Yoritomo named the spa after mountain flowers reflected on the water, like a carpet of blossoms. The clear water carries a faint hint of sulfur, soothes the skin and lets warmth linger long after bathing, ideal for unhurried soaks to the sound of the mountain stream.

Counted among Kusatsu's historic "Twelve Baths" since the Edo period, Kunshi no Yu is said to have been named in the Kan'ei era and still bubbles up west of the Yubatake, toward Sainokawara. Flowing naturally at 64.7 liters per minute, its clear water carries drifting white mineral flakes and a gentle sulfur aroma that distills the essence of Kusatsu.

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.

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 Bandaiko source, which unexpectedly erupted from within the Bandai Sulfur Mine in 1970, now stands as Kusatsu's primary hot spring, boasting the largest output and supporting the town. Named with the wish for 'eternal prosperity' (万代), this powerful source was born in the mountains, far from the Yubatake (Kusatsu's central hot-water field). Its colorless, transparent waters deliver a stimulating tingle that awakens both mind and body, while its robust warmth permeates to the very core. This energetic spring is a perfect companion for those seeking liberation from daily routines and a crisp mental and physical rejuvenation.

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.

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.

Beppu Onsen, one of the eight hot spring districts of Beppu, is the historic heart of the city, with springs rising in the streets between the station and the sea. This water blends two wells drilled in seaside Kitahama in equal parts. Sea-born salt and bicarbonate dissolve in nearly equal measure, pairing lasting warmth with a smooth feel on the skin in a gentle, neutral, pale-yellow bath.

This rare, naturally gushing source emerges from beneath 'Gensenkaku,' nestled beside Kusatsu Onsen's iconic Yubatake (Kusatsu's central hot-water field). Despite its strong acidity, its waters offer a remarkably soft bathing sensation, akin to being enveloped in silk floss. The milky-white waters, renowned for having Kusatsu's finest 'yunohana' (hot spring minerals), gently embrace the skin, contributing to silky skin and providing a restorative warmth that lingers deep within the body. Known as a 'phantom spring' for its history of disappearing once during the Taisho era, it now offers a profound escape from daily life, inviting deep relaxation and rejuvenation.

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. Gankutsu-no-Yu uses the natural rocks along the Mitoku River, and water rises on its own from the floor of each of its three tubs, sending small bubbles up around your feet.

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.

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.

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.

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.

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 Kusatsu Onsen, one of Japan's three most renowned hot springs, Jizo-no-yu has been cherished since ancient times, deeply intertwined with Kusatsu's unique `yumomi` (hot water stirring) culture. This powerful spring, known for its invigorating touch, seems to cleanse away physical and mental stagnation. It provides a deep, restorative warmth that penetrates to the core, offering a refreshing sensation akin to rejuvenation after your bath. Jizo-no-yu offers solace to travelers seeking relief from persistent fatigue or skin discomfort, and those desiring an authentic hot spring experience.

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.

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.

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.

The Uwanari Gensen is a primary source for Arima Onsen's famous "Kinsen" (Golden Spring). Its name, meaning "jealousy spring," comes from a legend that the water would gush violently with envy whenever a beautiful woman passed by. [3, 6, 7] Once an intermittent spring, it is now drilled and its waters are distributed to many establishments in Arima via other sources like the Gosho Sengen. [3, 6, 7] Rich in iron and salt, this spring is known for its characteristic reddish-brown color upon oxidation and its ability to warm the body to its core.

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.

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.

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 Shari Onsen source gushed from a 1,000 m borehole in 1976 beside the Shari River near the town center of Shari, the gateway to Shiretoko. Drilling began after a slope was spotted where snow melted first each spring, and the water has since been piped to local inns, a community rest house and nearby homes. Clear and pale brown like oolong tea, this moor water carries plant-derived humus, and its slippery touch leaves skin soft and smooth, gently easing the fatigue of travel.

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.

The Yuhanazawa No.3, No.5 and No.6 Combined Source gathers three springs welling up in the Yuhanazawa district of Takayu Onsen, a spa said to have opened in the Keicho era and once counted among the "Three Takayu of Oshu" alongside Zao and Shirabu. Tart at pH 2.6 and scented with powdery sulfur, its water gushes from the spouts in a blizzard of white mineral flakes, steeping the tubs in a milky blue. It suits travelers seeking a genuine mountain sulfur soak.

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.

Nekonaki Onsen rises beside the Kitasu River in Ishikawa, central Fukushima. Legend says that when the Heian-era poet Izumi Shikibu left for the capital, her cat cried for her until it fell ill, then recovered by bathing here, giving the spring its name, "crying cat." The Ishikawa area is dotted with radioactive springs, and Izutsuya Onsen No. 2, pumped from the ground at 18.4°C, is a cold mineral spring. Its total mineral content is a light 128.2 mg/kg, yet carbonate ions reach 36.1 mg, giving it a strongly alkaline pH of 10.1.