Hot Spring (Onsen) (温泉)

The term "hot spring "refers to a phenomenon of hot water gushing out from underground, the state of hot water or the place where such phenomenon or state is seen. Also, bathing facilities which use such hot water are generally called hot springs.

Based on the type of heat source, hot springs are divided into volcanic hot springs whose heat source is underground magma of volcanoes and non-volcanic hot springs which are not related to volcanoes.

Depending on contained ingredients, there are a variety of hot springs in terms of color, smell and health benefits.

Hot spring in the broad sense (hot springs defined by the law: In order to be defined as hot springs, according to the Japanese Hot Spring Law, water in question is not necessarily required to be hot so long as it is natural and special water that is different from normal water (mineral water) or it gushes out together with volcanic gas (refer to the definition of hot springs). When a certain hot spring is questionable whether it is a real hot spring or not, discussions are generally focused on whether it is a 'legal hot spring' which meets the requirement of the law or not (sometimes questions are also raised whether it fits people's conceived image of a hot springs).

Origin of hot springs

Water which is heated by geothermal heat is defined as hot spring so long as it satisfies the requirement of the Hot Spring Law, regardless of whether it gushes out naturally or it was pumped out artificially by boring machines (even if it is a man-made hot spring). Based on the type of heat source, hot springs are divided into volcanic hot springs whose heat source is underground magma of volcanoes and non-volcanic hot springs which are not related to volcanoes. Non-volcanic hot springs are further divided into deep hot water, which was heated by geothermal heat that becomes higher according to the geothermal gradient, and those whose heat source is unknown. As the exceptional case, a moor hot spring, with water that was heated by the reaction of heat generated when ancient sedimentary plants turned into brown coal, exists at Tokachigawa-Onsen Hot Spring in Hokkaido. Needless to say, volcanic hot springs are located near volcanoes and contain ingredients originating from volcanic gas. As deep hot water is often situated deep underground of plains and/or basins, it is normally pumped out by boring machines and accordingly it sometimes contains salt and/or organic matter that originated in the sea. The temperature of some non-volcanic hot springs (such as Arima-Onsen Hot Spring, Yunomine-Onsen Hot Spring and Matsunoyama-Onsen Hot Spring) is extremely high to the extent that the geothermal gradient alone cannot explain. Though some theories have been proposed concerning the heat source and ingredients of such hot springs, all of them are still in the hypotheses stage.

Hot springs in Japan

As there are many volcanoes in Japan, there are many volcanic hot springs and many legends or mythologies related to hot springs have been passed down. For hot springs that have a long history, the record of their use is also found in old literature.

According to Nihonshoki (Chronicles of Japan), Shoku Nihongi (Chronicles of Japan continued), Manyoshu (Collection of Thousand leaves) and Shui Wakashu (Collection of Gleanings of Japanese Poems), Tamatsukuri-onsen Hot Spring, Arima-onsen Hot Spring, Dogo-onsen Hot Spring, Nanki-Shirahama-onsen Hot Spring and Akiu-onsen Hot Spring were used for the Shinto rituals for purification and the Emperors' visits to hot springs. In the Engishiki Shinmyo Cho (list of jinja shrines) compiled during the Heian period, several shrines, including Onsen-jinja Shrine, whose enshrined deity was the deity of hot spring were listed.

During the Edo period, Ekken KAIBARA, Gonzan GOTO and Yoan UDAGAWA etc. published books concerning spa therapy as well as picture guides of hot springs and hot springs became popular among ordinary citizens. At that time, hot springs were separated into zatto (hot springs for common people), the ones which were open to ordinary citizens, and tonosamayu (hot springs for people with higher rank) or kagiyu (hot springs for people with higher rank), which were used only by shogunate officials, local governors and the lords of domains. These were called 'choninyu' (hot springs for merchants) and 'samuraiyu' (hot springs for samurai warriors) respectively. Each domain established a hot spring office and the chief of such an office called Yubugyo or Yubetto was in charge of collecting hot spring tax.

As a practice, ordinary citizens visited hot springs for the purpose of seasonal toji (hot spring cure) such as Shogatsu no yu (new year toji), Kan toji (winter toji), Hana toji (spring toji) and Aki toji (autumn toji). They regularly visited the same hot spring every year for the purpose of fatigue recovery and health promotion. Further, 'toji customs, ' which still remain at present, had taken root during the Edo period. Varieties of toji customs, such as mineral sand bath, cascading bath, steam hot bath and mixed bath, were created taking advantage of the characteristics of respective hot springs.

Thanks to the explosive spread in the use of boring technology called Kazusa-bori around the end of 19th century, a lot of new hot springs became available during the Meiji period. Drilling hot springs at Beppu-onsen Hot Spring, whose number of hot spring wells accounts for about 1/10 of Japan's aggregate number, was also bolstered by this technology. At present, a plural number of hot spring suppliers are supporting Beppu-onsen Hot Spring whose number of hot spring wells and the yield of hot water is the largest in Japan.

Hot springs and therapy

During the Meiji period, scientific research of hot springs became vigorous. Since the Showa period, the medical effect of hot springs has been verified thanks to the advance of hot spring medicine and analytical chemistry and the range of users of hot springs have widened. At Beppu-onsen Hot Spring where hot spring resources are abundant, a Military hospital was established in 1912 and a Naval hospital was also established in 1925. In 1931, Research Institute of Balneotherapeutics of Kyushu University was established and the research of hot spring therapy has been conducted there.

Spread of city hot springs

In recent years, drilling hot springs has been vigorously conducted around the nation with the aim of regional development and attracting tourists. Even in big cities like Tokyo, bathhouses whose draws are hot springs have started business and are attracting many clients.

Hot springs in Europe

While hot springs have been used basically for bathing in Japan, they have been mainly used in Europe for drinking as well as for resorts where people enjoy sun-bathing and air-bathing. Even at present, it is permitted as medical practice to drink mineral water, to bathe for pre-determined time and to have a massage while taking a shower.

Karlovy Vary in Czech, Bath in U.K., Spa in Belgium, Budapest in Hungary and Baden-Baden in Germany are the famous hot springs in Europe. As for details, refer to the items to be mentioned later.

Use of hot springs

During the era when the use of hot water for bathing was not common and the knowledge of hygiene and medical care was insufficient, hot spring was highly valued because of its marvelous benefits for injuries and diseases. In the legends related to the origin of hot springs, many tales are found such as the one saying to the effect that a dear, a crane or an egret successfully cured their injuries and the one saying to the effect that famous Buddhist monks, such as Kukai, discovered the hot spring. Such hot springs were either owned by temples/shrines or co-owned by neighboring communities.

In the Edo period, increasing guests visited for toji in agricultural off-season and the facilities to accommodate them became hot spring hotels. The pattern of toji also shifted from long-stay type to overnight type, which is similar to the current ones.

Though the use of hot springs is considered as one of medical treatment in Europe, hot springs are used in Japan basically for a recreational purpose as part of sightseeing tour. Many hot springs are used by schools as a lodge for training and school excursions. Needless to say, there still exist guests whose purpose is toji.

Pattern of hot water provision

Hot springs are divided into a type of circulating bath, which recycles hot spring water once poured into a bath, and the type of kakenagashi, which uses fresh hot spring water without recycling. A circulating-type bath uses the once used hot spring water after filtrating and sterilizing by heating. As the increasing number of guests recently prefer the kakenagashi-type, some hot springs are using the catchphrase saying "100 % fresh hot spring water" in their advertising.

Bathing patterns

Varieties in the temperature of hot spring water

Bathing within time-limits

Kusatsu-onsen Hot Spring (Gunma Prefecture, high-temperature bathing (above 42 degree Celsius))

Bathing in tepid hot spring water/long time bathing

Bathing in hot spring water with insensible temperature (34-37 degree Celsius), Bathing in tepid hot spring water 37 - 39 degree Celsius)

Bathing in cold spring water

Masutomi-onsen Hot Spring (Yamanashi Prefecture), Kannojigoku-onsen Hot Spring (Oita Prefecture)
Varieties in the way of bathing

Utaseyu (Cascading bathing)

Utase-daiyokujo (Sujiyu-onsen Hot Spring, Oita Prefecture), Hyotan Onsen (Beppu-onsen Hot Spring Kannawa-onsen Hot Spring)


Hita-onsen Hot Spring (Oita Prefecture)

Tachiyu (standing bathing)

Namari-onsen Hot Spring (Iwate Prefecture)

Neyu (lying bathing)

Yonodani-onsen Hot Spring

Ashiyu (foot bathing)

Facilities are set at many places and many of them are free of charge. The one which set at Michi-no-eki Tarumizu (Kagoshima Prefecture) has the longest bench in Japan.

Mushiyu (steam bathing)

Ishimuro (rock chamber)

Kannawa steam bath (spread with crude drug of sweet flags: Beppu-onsen Hot Spring Kannawa-onsen Hot Spring in Oita Prefecture)

Hakomushi (box sauna)

Goshogake-onsen Hot Spring (Akita Prefecture)

Sunamushi (mineral sand bath)

Ibusuki-onsen Hot Spring (Kagoshima Prefecture), Takegawara-onsen Hot Spring (Beppu-onsen Hot Spring in Oita Prefecture), Beppu Kaihin Sunayu (Shoninhama Beach at Kamekawa Spa, Beppu-onsen Hot Spring in Oita Prefecture)

Manju-fukashi (a kind of steam bath)

Sugayu-onsen Hot Spring (Aomori Prefecture)

Ganbanyoku (a kind of stone sauna)

Tamagawa-onsen Hot Spring (Akita Prefecture) (Akita Prefecture)

Doroyu (mud bath)

Onsen Hoyo Land Resort (Beppu-onsen Hot Spring Myoban-onsen Hot Spring in Oita Prefecture), Suzume-no-yu (Jigoku-onsen Hot Spring in Kumamoto Prefecture), Misasa-onsen Hot Spring (Tottori Prefecture), Goshogake-onsen Hot Spring (Akita Prefecture)

Insen (drinking hot spring water)

At each place, when drinking, attention should be paid as it may damage health depending on the person.

Yunohana House

The production technique of yunohana at Beppu-onsen Hot Spring Myoban-onsen Hot Spring (Myoban) is designated as important intangible assets of folk culture.

Jigoku-mushi (boiled in hot steam of hot springs)

Those produced at Beppu-onsen Hot Spring Kannawa-onsen Hot Spring in Beppu City are well-known. Fish and/or vegetables are steamed in the Jigokugama (pot) which uses hot spring steam. The advantage of this cooking method is to retain ingredients.

Onsen tamago (eggs boiled in hot spring water)

Eggs are boiled in high-temperature spring water.

At Nozawa-onsen Hot Spring (Nagano Prefecture), hot spring water is used for the preparation of Nozawana pickles as well as boiling frozen Nozawana in winter. Further, it is well-known that local people use a public bath for the preparation of Nozawana.

Onsen natto (hot spring fermented soybeans)

Onsen natto is produced at Kuroishi-onsenkyo Spa and Shima-onsen Hot Spring etc.


Thanks to the joint research conducted by the Medical Department of Oita University, Hiroshima University, Nippon Bunri University, University and Padua and Oita Industrial Research Institute, Fangotica, material used for hot spring mud cosmetology, was developed in Beppu City with the use of hot spring mud of various colors collected at the sources of hot spring.

Definition of hot springs

In Japan, hot springs are defined by the Hot Spring Law and the Standard Methods of Analysis for Mineral Springs published by the Ministry of Environment.

Elements of a hot spring

The following are the elements that make up hot springs.


Temperture means water temperature measured at the gushing point (normally the earth's surface). According to the Standard Method of Analysis for Mineral Springs, they are categorized, based upon their temperature, into cold mineral springs, tepid hot springs, hot springs, and high-temperature hot springs.

Categorization based on temperature are not standardized globally because governments and people in charge of categorization use different names and/or temperature range for categorization.

Dissolved ingredients (quality of springs)

Dissolved ingredients are categorized based on the man-made regulations. In Japan, the Hot Spring Law and the Standard Methods of Analysis for Mineral Springs regulate in this regard. The Standard Methods of Analysis for Mineral Springs designate mineral springs that are suitable for cures as Ryoyosen (medical hot spring) and stipulates the details of specific eight ingredients. Categorization of dissolved ingredients are done based upon the mass of dissolved ingredients contained in 1 kg of hot spring water.

Yeild of hot spring water

Yield of hot spring water means the volume of water that is continuously taken from underground to the surface of earth inclusive of water that is pumped out artificially by motors, etc.

As the three elements of hot springs are useful for understanding the characteristics of each hot spring, various categorization and regulations are stipulated based upon physical & chemical characteristics.

Osmotic pressure

Based on Osmotic pressure, the Standard Methods of Analysis for Mineral Springs categorizes hot springs into those of low tonicity, isotonicity, and high tonicity in accordance with the mass of dissolved ingredients contained in 1 kg of hot spring water or their freezing points.

Definition of hot springs based upon the Hot Spring Law

In Japan, the Hot Spring Law was established on July 10, 1948. According to Article 2 (Definition) of the Hot Spring Law, hot spring is defined as 'hot water, mineral water, and water vapor and other gas (excluding natural gas of which principal component is carbon hydride) that satisfies one or more of the following criteria' (hot spring in broad sense based on the law).

Temperature of water at the gushing point shall be 25 degree Celsius or above. (Those of which temperature is below 25 degree Celsius could be called cold spring or mineral spring).

One or more of following components shall be contained.
(contained amount is measured in 1 kg of water)

Dissolved matter (exclusive of gaseous matter)
Aggregate amount 1000 mg or more

Free carbon dioxide (CO2): 250 mg or more

Lithium ion (Li+): 1mg or more

Strontium ion (Sr++): 10 mg or more

Barium ion (Ba++): 5 mg or more

Iron ion (Fe++,Fe+++): 10 mg or more

Manganese ion (Mn++): 10 mg or more

Hydrogen ion (H+): 1 mg or more

Bromine ion (Br-): 5 mg or more

Iodine ion (I-): 1mg or more

Fluorine ion (F-): 2 mg or more

Hydro arsenic acid ion (HAsO4--): 1.3 mg or more

Diarsenic trioxide (HAsO2): 1mg or more

Total sulfur (S) substances corresponding to HS-,S2O3--,H2S: 1mg or more

Metabolic acid (HBO2): 5 mg or more (a kind of chloride which is effective for sterilizing and disinfecting). It is used for washing and disinfecting eyes at ophthalmological clinics.

Silicic acid (H2SiO3): 50 mg or more (it is effective for retaining warmth)

Sodium hydrogen carbonate (NaHCO3): 340 mg or more

Radon (Rn): 20 or more (unit: ten ppb curie)

Radium salt (as RA): A fraction of 100 million mg or more

Categorization based on the Standard Methods of Analysis for Mineral Springs

According to the Standard Methods of Analysis for Mineral Springs issued by the Ministry of Environment, spring water is categorized into 'ordinary water' and 'mineral water.'

Spring water is designated as 'mineral water' if its temperature at the gushing point is 25 degree Celsius or above or it contains designated ingredients more than the designated amount.
(refer to mineral spring)

Temperature of spring water

The Standard Methods of Analysis for Mineral Springs categorizes spring water into four based on its temperature at the gushing point or when it was taken.

Cold mineral springs

Below 25 degree Celsius

Tepid hot springs

25 degree Celsius to 34 degree Celsius (exclusive of 34 degree Celsius)

Hot springs

34 degree Celsius to 42 degree Celsius (exclusive of 42 degree Celsius) (hot spring in narrow sense)

High-temperature hot springs

42 degree Celsius and above

Categorization of the water quality

pH value

Categorization based on the pH value at the gushing point

Acidic springs

Below pH 3

Mildly acidic springs

pH 3 to pH 6 (exclusive of pH 6)

Neutral springs

pH 6 to pH 7.5 (exclusive of pH 7.5)

Mildly alkaline springs

pH 7.5 to pH 8.5 (exclusive of pH 8.5)

Alkaline springs

pH 8.5 or above

Categorization of osmotic pressure

Categorization based the mass of dissolved ingredients and congealing point (freezing point)

Low tonicity springs

Mass of dissolved ingredients: less than 8 g/kg, freezing point: -0.55℃ or above

Isotonicity springs

Mass of dissolved ingredients: 8 g/kg to 10 g/kg (exclusive of 10 g/kg), freezing point: 0.55℃ (exclusive of 0.55℃) to -0.58℃

High tonicity springs

Mass of dissolved ingredients: 10 g/kg or more, freezing point: below 0.58℃

Medical springs

The Standard Methods of Analysis for Mineral Springs designates mineral springs that are suitable for cures as Ryoyosen (medical hot spring) and stipulates the details of specific eight ingredients.

Springs are allowed to be called medical springs based upon the Standard Methods of Analysis for Mineral Springs if the temperature at the source is 25 degrees or above or the spring water contains any of following ingredients more than the designated amount measured in 1 kg of water.

Mass of dissolved ingredients (excluding those that are in the form of gas)

1000 mg

Liberated carbon dioxide

1000 mg



Total iron ion (Fe2++Fe3+)

20 mg


100 mg



Total sulfur (substances corresponding to HS-,S2O3-- and H2S)

2 mg



Medical springs are further categorized as follows based on the dissolved ingredients and their amounts.

Salt springs

Mass of dissolved ingredients (exclusive of those that are in the form of gas) 1g/kg or above

Simple hot springs

Mass of dissolved ingredients (excluding those that are in the form of gas) below 1 g/kg as well as temperature is 25 degree or above.

Medical springs that contain specified ingredients

Springs that contain specified ingredients more than the designated amount

Varieties of hot springs

Hot springs are categorized based on their ingredients. Further, the results of the above categorization are shown in three ways as Keijiyo senshitsumei (name of recognized spring quality), Kyu senshitsumei (old name for spring quality) and Shin senshitsumei (new name for spring quality). The following are categorizations based on Keijiyo senshitsumei. For categorization of hot springs, also refer to the quality of hot springs. Health benefits of each type of hot spring described below are mere yardsticks and attention should be paid to the fact that such descriptions don't guarantee health benefits to all people.

Simple hot springs

Simple hot springs are hot springs whereby the amount of contained minerals and gas are less (less than 1 g per 1 kg of hot spring water). They are not so pungent and mild to skin. They are clear and colorless and have neither taste nor smell. They are believed to be effective for neuralgia, muscle pain, arthralgia, blows, sprains, sensitivity to cold, fatigue recovery and health promotion. However, these are not the effect of contained ingredients, but the effect of improved circulation resulting from the warm bath.

Simple hot springs are often misunderstood as low quality hot springs since they contain little ingredients. The definition of simple hot spring is made solely based upon the amount of contained ingredients and the kinds of ingredients are not taken into account. Even though categorized into simple hot springs, the quality of each hot spring varies widely and simple comparison/categorization of them is not possible. Depending upon the relative proportions of each ingredient, some simple hot springs have similar quality with hot springs that are described below. Further, some simple hot springs have good quality with small amount of various ingredients contained in proper balance.

Sulfur springs

Sulfur springs are hot springs which contain 2 mg or more of total sulfur in 1 kg of hot spring water. They are white-colored and have the smell of addled eggs. Their temperature is relatively high and they are effective for pimples, oily skin, skin diseases, rheumatism, bronchial asthma and women's diseases. They are also effective for diabetes since sulfur ion promotes the production of insulin. Hydrogen sulfide is poisonous and strongly irritates mucosae, skins and respiratory organs. Persons whose physical strength has declined due to illness or those with dry skin should pay attention in particular. Sometimes it is not appropriate for the patients of rheumatism and asthma to bathe in sulfur hot springs without careful consideration. When the patient in question wants to bathe in sulfur hot springs, it is desirable to consult a doctor in advance. As hydrogen sulfide corrodes metals, accessories made of metals other than gold and platinum should be removed from the body. In particular, silver reacts strongly to sulfur and becomes black losing its gloss.

Chloride springs

Chloride springs are hot springs that contain 1 g or more of ingredients in 1 kg of hot spring water and the principal ingredients of negative ions are chloride ions. They are principally effective for injuries, chronic skin diseases, blows, sprains, chronic rheumatism, infertility, gout and vascular sclerosis. Drinking of chloride spring water is effective for chronic digestive diseases (drinking should be done according to instructions from a doctor, at the place where drinking is permitted as well as in compliance with the necessary precautions).

Ferruginous springs

Ferruginous springs are hot springs that contain 20 mg or more of total iron ion in 1 kg of hot spring water. Their color is brownish-red because iron contained in the water becomes oxidized upon exposure to air. They have the effect of sterilizing and disinfecting. As this type of hot springs has a high moisturizing effect, they are effective for warming the body as well as for anemia.

Cupriferous and ferruginous springs

Cupriferous and ferruginous springs are hot springs that contain copper and iron. Their color is yellow because metals contained in the water become oxidized upon exposure to air. Like in the case of ferruginous springs, there are two kinds of cupriferous and ferruginous springs, namely hydrogen carbonate springs and sulfate springs. They are effective for blood diseases and high blood pressure.

Aluminous springs

Aluminous springs are hot springs whose principal ingredient is aluminum. Their Kyu senshitsumei is Myobansen (alum spring) or Ryokubansen (melanterite spring) etc. They have the effect of sterilizing and disinfecting. They are effective for the recovery of a firm skin as well as chronic skin diseases, athlete's foot and hives. Myobansen is believed to be effective for eye problems in particular.

Acidic springs

Acidic springs are hot springs that contain a mass of hydrogen ion. In many cases, hydrogen ion is contained in the water in the form of liberated sulfuric acid or hydrochloric acid. They are pungent and effective for sterilizing. They are also effective for enhancing natural healing ability by stimulating new skin while removing old skin. They are effective for chronic skin diseases such as athlete's foot and eczema. Persons whose skin is sensitive are required to either refrain from bathing or should wash their body thoroughly with fresh water after bathing.

Hydrogen carbonate springs

Hydrogen carbonate springs are springs that contain acids and bases. Hydrogen carbonate springs are divided into sodium hydrogen carbonate springs and bicarbonate-earth springs. Sodium bicarbonate springs are believed to be effective for making skin smooth and beautiful. They are also effective for fatigue recovery, recuperation after illness, injuries and skin diseases. Drinking this spring water is said to be effective for stomach inflammation. As bicarbonate-earth springs have an anti-inflammation effect, they are effective for injuries, skin diseases, atopic dermatitis and allergy diseases. Drinking this water is believed to be effective for gout, uric acid stones and diabetes. Though these types of hot springs are suitable for everybody, minimal inflammation could occur, depending on the strength of alkaline, on the areas where skin is sensitive. Though such inflammation is temporary in nature, it is desirable for persons with sensitive skin to wash their bodies with fresh water after bathing.

Carbon dioxide springs

Carbon dioxide springs are hot springs which contain 1 g or more of liberated carbonic acid in 1 kg of hot spring water. They are effective for improving heart disease and high blood pressure. Drinking this water is believed to be effective for constipation and anorexia. As the above effects are resulted from lowering oxygen partial pressure in the blood, persons with cardiovascular or respiratory diseases should be careful when bathing as bathing could worsen their condition due to excessive stimulation. When such patients want to bathe in carbon dioxide springs, it is desirable for them to consult a doctor in advance. Even if permitted to bathe, it is better to avoid prolonged bathing.

Radioactive springs

Radioactive springs are hot springs which contain 3 nanocuries or more of Radon in 1 kg of hot spring water. It is contemplated that radiation emitted from such ingredient is unlikely to cause injury to human bodies and it might be good for health since it activates immunity by the Hormesis effect.

This type of hot spring is believed to be effective for various diseases, including skin diseases, women's diseases and injuries. They are especially effective for gout, low blood pressure and cardiovascular problems. It is also said that such radiation could hinder cancer growth. However, as any of diseases mentioned above have not been firmly proved to be susceptible to radiation and therefore, research in this regard is expected. Misasa Medical Center of Okayama University Medical School has been established at Misasa-onsen Hot Spring with the aim of proving the therapeutic efficacy of Radon hot springs and is conducting research activities on a full-scale.

Sulfate springs

Sulfate springs containing hydrosulfate. They have a bitter taste. Sulfate springs are divided into sodium sulfate springs, gypsum springs, and magnesium sulfate springs. They have the effect of improving the circulation of blood. They are effective for injuries, gout, stiff shoulder, low back pain, and neuralgia. Drinking the water is effective for constipation and hives. As hydrosulfate has the effect of easing the stiff part (stiff skin) and making easier to move, sulfate springs are quite effective for gout and neuralgia. Among sulfate springs, those containing calcium sulfate have thick and smooth tactile impression. This is because calcium sulfate is the component of gypsum. Though in rare cases, sulfate springs are misunderstood as dangerous because they contain sulfuric acid. While sulfuric acid is hazardous substance, sodium sulfate and magnesium sulfate etc. are harmless substances. Unlike hydrogen sulfide springs, they don't emit a bad smell. Sulfate springs have no particular harmful influence on human bodies except for persons who are prohibited to bathe in hot springs. Many house-hold bath agents have a similar composition as that found in sulfate springs.

Onsen mark (the symbol for hot spring)

The notational system of character reference to Onsen mark is ♨ (♨).

There are three views on its origin. Concerning the details, refer to Onsen mark.

Hot springs around the world

The purposes of the use of hot springs around the world are basically divided into several categories; namely, taking a rest through bathing (it is mainstream in Japan), recuperation by bathing, enjoying while bathing (such as swimming), drinking (drinking of hot spring water) and utilizing steam (sauna and steam bath). Taking a rest by bathing is a unique Japanese culture which reflects its humid climate (Japanese-style bathing is spread exceptionally in some regions in Asia). Globally, hot springs are considered to be used for enjoying, healing, drinking or steaming. However, thanks to the current Japanese cultural boom as well as the spread of Onsen culture (to be mentioned later), Japanese-style bathing is gradually spreading globally.

Hot springs in Europe

In Europe, 'drinking hot spring water,' namely drinking of hot spring water, is deeply rooted as hot spring culture in particular. Carlsbad, a famous hot spring after which the name of Carls hot spring was created, is a hot spring for drinking.

In Europe, however, bathing was the mainstream up to 15th century. However, hot spring resorts didn't develop there because of the small quantity of hot spring water as well as its low temperature resulting from the lack of a volcanic belt. In addition, bathing was considered to be harmful for a body due to the spread of infectious diseases, such as the plague, as well as social background including religious reasons and the practice of bathing was shied away from by people (concerning the details, refer to the item of bathing). On the other hand, as the quality of drinking water was poor in Europe, some visitors to hot spring resorts used to drink hot spring water. Many of the hot spring resorts took advantage of the above and started to sell bottled hot spring water. Such bottled hot spring water gained a good reputation and since then, the notion of "hot spring was water to drink," namely the practice of drinking hot spring water took root as culture. Evian (mineral water) and Vichy, well-known brand of bottled water, make use of hot spring water. In Japan, Wilkinson Ginger Ail originally used hot spring water as an ingredient.

As the drinking of hot spring water showed clear medical effects, it was soon associated with medical science. In Japan, by contrast, spa therapy had been deemed as folk therapy for a while because of the adoration for the newly imported western medicine and spa research was delayed.
(However, research activities was continuously conducted at Beppu-onsen Hot Spring, where the big-scale facilities for sick and wounded soldiers were operated by Army/Navy, and Misasa-onsen Hot Spring by establishing a hot spring hospital and in cooperation with neighboring universities.)

Bath and Carlsbad, well-known as the town of hot spring currently, have developed as health resorts and there are hot spring hospitals and nursing homes at present. Like in Japan, recuperation in a hot spring is also common in Europe. Although hotels and restaurants also exist, they don't have the facilities for hot spring bathing inside the building (the fact that the climate in Europe, especially in west and east Europe, is not so humid as Japan is a big reason why the culture of bathing has not developed). Instead, they have facilities for drinking hot spring water and hot spring water drinking bars (bar).

By contrast, limited number of hot spring resorts, such as Baden-Baden and Spa, were places for bathing originally. Unlike in Japan, however, the notion of 'soaking' doesn't exist even at these places. Baden-Baden in Germany has developed as a resort town where casinos, boutiques, jewel shops and high-grade hotels are located, rather than as a hot spring resort. Hot spring water is also used for saunas and showers. Other than the above, there are public baths and many people swim in a big bath using hot spring water in the same fashion as in a swimming pool (swimming is deemed as the breach of manners in Japan). Unlike in Japan, the practice of bathing naked doesn't exist in Europe and people wear swimsuits. Therefore, many of baths have no seperation between men and women. In this sense, public baths can be said as the place where people get used to hot water, something like hot swimming pools in Japan. The situation in New Zealand to be mentioned later is similar to Europe.

Spas in Belgium, which have became the common name for international hot spring resorts, have developed as hot springs for recuperation. As its hot spring district is small and baths for recuperation are set in each hotel room, its atmosphere resembles to that of hot springs for toji in Japan. However, bathing is done solely for the purpose of recuperation and unlike in Japan, the notion of "soaking leisurely and relieving fatigue" doesn't exist.

Hot spring culture in Hungary, where public baths were constructed during the ancient Roman period, has a history of nearly 2000 years. Budapest is rich in hot springs. There also exists a hot water lake (Lake Hévíz).

Hot springs in the U.S.

In America, some hot springs are scattered along the volcanic belt, though the number is less than in Japan. The most famous one among them are the Hot Springs in Arkansas. In 1541, the Spanish discovered a hot spring which had been used by indigenous people from long ago and named it Hot Springs (namely, the place where hot water gushes out). However, in spite of the abundant quantity of hot spring water, bathing is not necessary there because the humidity level is as low as in Europe. Therefore, hot spring water is only used for showers, saunas and massage and the development of the town is supported by casinos and resort facilities. Further, hot spring water of Hot Springs has been believed to be good for health without concrete grounds and there has been no affiliation between hot springs and medical science. Under such circumstances, hot spring exploitation itself is in the stage of development relative to the size of the country.

Hot springs in Asian countries

Hot spring culture of "soaking," similar to that of Japan, is rooted in the Republic of Korea. This is the result of Japanese people's exploitation of hot springs in Korean Peninsula in the wake of Japan's annexation of Korean Peninsula. Though there are few volcanoes in Korea, there are a lot of hot springs with high temperatures. Japanese people who visit hot springs in Korea for the first time sometimes suffer culture shock due to the difference in culture between two countries (for example, Koreans bring nothing when bathing). There exists traditional steam bath called Asemushi (sweat sauna).

Hot springs in Oceania

In Oceania, New Zealand is famous for having a lot of hot springs. There are many hot springs thanks to the presence of many volcanoes. Indigenous people Maori knew the benefits of hot springs and used them for recuperation. In the early 20th century, New Zealand strived to develop hot spring resorts nationwide taking advantage of its abundant hot spring water. Such development, however, didn't progress very much because its climate was not as humid as that of Japan and the practice of bathing was not prevalent among the white people who settled there. At present, the use of hot springs in New Zealand is linked with healthcare activities, such as sports and exercise, and hot springs have developed as health resorts where people shed sweat after participating in sports and/or outdoor activities. Swimming pools which use hot spring water are very popular among people and the core facilities of a hot spring town.


The movement to make 'Onsen' a global term started around 2003. This movement was prompted by the fact that the commonly used English translation of Onsen, 'Hot Spring' and 'Spa,' mean the place where hot water gushes and hot springs for recuperation respectively (the latter derives from the city name Spa (Belgium) which is famous as the host city of Formula 1 World Championship) and both of them evoke the image of something different from the Japanese Onsen. People of Kusatsu-onsen Hot Spring are actively conducting the movement to make 'Onsen' a global term. The 'ONSEN Tourism Department' exists in the administrative organization of Beppu City.

Probably thanks to the above, foreign tourists whose main purpose is visiting Onsen have been increasing recently. Tours from abroad that specialize in Onsen as well as English web-sites introducing Onsen at various places in Japan are also seen recently.
(de Thermalquelle)

[Original Japanese]