Japanese Onsen - Natural Hot Springs

You hot spring (温泉) are natural volcanic hot springs that are appreciated and help to relax, also bringing numerous health benefits. In this article, we will talk in detail about these Japanese hot springs.

For those who don't know, Japan is a volcanic country full of natural as well as man-made hot springs, it's no exaggeration to say that Onsen are Japan's passion. There are thousands of varieties of hot springs in Japan.

Visiting the bathhouses and hot springs is part of Japanese culture, since childhood, families frequent this place and enjoy the numerous benefits that hot springs offer.

In the hot springs, people have to bathe naked, causing a lot of discomfort to Westerners, but it is something extremely normal among the Japanese. The bathrooms are separated by sex, but in the old days the hot springs had mixed bath.

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Onsen - natural hot springs in Japan

Some facts about onsen

Research claims that there are over 30,000 natural hot springs across Japan. Being more than 3,000 resorts and thousands more spread across mountains and cities. If we count the unnaturals, the numbers go beyond 100,000.

Visitors usually use a small towel-apron. Some places allow the Japanese to enter the water with the towel. Otherwise the Japanese usually place the folded towel on their head or in the corner of the pool.

Visitors must wash and dry off before entering the hot water. The indoor baths provide small benches for visitors to sit on and take a shower.

Onsen - natural hot springs in Japan

Many traditional hot springs in Rural Japan have rules prohibiting the use of robes in the bath, arguing that it makes cleaning more difficult. While others are allowed to access the site wearing a yukata, rarely will any onsen allow anyone to enter the water with clothes on.

The purity of the water is very important in the onsen, so people need to bathe naked and take a shower before entering the thermal pools. Not even the towel can touch the water.

Young children can accompany a parent during the bath, regardless of gender. The girls who accompany their father to the men's bath wear clothes and bikinis. In some hot springs in the mountains, you can even come across mischievous monkeys.

Onsen - natural hot springs in Japan

The hot springs are generally considered a refuge from the hectic, stressful life that the Japanese lead, the springs have a calm and relaxing atmosphere. Many hot springs have an image of Mount Fuji on the walls, which by tradition encourages calm and meditation.

The waters are generally rich in minerals. Water mineral content and PH levels vary greatly from one onsen to the next. The waters can be rich in iron, sodium chloride, sulfur, carbon or radium.

One of the purposes of Japanese hot springs is to cure some illness. There is a type of source for each disease. Couples who are trying to get pregnant go on an Onsen. Seniors go to the spa to improve circulation or soothe joint pain.

Onsen - natural hot springs in Japan

The waters of the springs are considered hot in the west from 21 degrees, while the hot springs in Japan are only classified from 25 degrees. The water must have at least 1 of 19 types of minerals.

Hot springs are one of the ways to connect with nature and people. It is common to talk to strangers. Many Japanese firmly believe that in hot springs you can make friends, have fun with co-workers, couples and family.

Remembering that each Onsen has its rules, there are labels and ways to bathe in thermal water.

Read more: How to bathe in Japan's Hot Springs

Rotenburo - open air onsen

Rotenburo they are outdoor onsen and are considered more desirable than indoor spas. Part of the onsen experience is connecting with nature, something you can only find visiting these remote mountain hot springs.

Onsen - natural hot springs in Japan
Onsen hot spring

Many rotenburo have a great view of the mountain, forest or sea. In northern regions of Japan the Rotenburo is surrounded by snow. Some rotenburo they are pools that arose naturally, without human interference.

Many rotenburu-style onsen are built by resorts and hotels. The best rotenburo are constructed of natural materials, they are generally landscaped and maintain privacy for visitors.

Some onsen in cities tend to reserve a more natural spot similar to rotenburo. Even in a multi-story building it is possible to find an onsen where a part of it is exposed to the open air, without any covering.

Onsen - natural hot springs in Japan
Monkey on the Onsen

Private Onsens – Some Hotels and Resorts offer a private onsen in the rooms, they are small bathtubs with artificial or natural thermal water. Other onsen also offer private rooms for couples and friends.

Konyoku onsen - Mixed bath

Konyoku are mixed-sex onsen that are found in rural areas. In some cities like Tokyo, Konyoku are illegal. I've visited a mixed onsen on the mountain, where the pools were enclosed in small rooms and yukata were worn to get from one location to another, making it nearly impossible to see a naked woman as some would like.

Konyoku were quite popular in the Edo period, with western influence this became uncommon. Although some places allow mixed bathing, most of the public at these baths is over 60 years old, probably young people have created shame and do not frequent these mixed places.

We have already written an article talking in detail about mixed baths and how to find them in Japan. Mixed baths are called konyokuburo (混浴風呂) and are more organized than you might think. 

To learn more, read: Are there still hot springs or onsen with mixed baths in Japan?

Onsen - natural hot springs in Japan

The article is still halfway through, but we recommend also reading:

Sento - Spa in the city

Sento are similar to onsen, except that their water is heated artificially. Sento often use normal water that does not have the mineral properties of onsen. Sento are often found in urban areas.

In the past, many families did not have a bathtub at home, so it is common for them to go to a small sento. Even though today most people have a hot tub at home, sentos are still very popular in Japan.

Onsen - natural hot springs in Japan
I feel

Types of water and bathing in the onsen

Each Onsen has its natural water type, each with its own benefit. We already wrote an article about this, but let's list some of the types of water that we find in Japanese hot springs:

Chloride - Enka butsusen (塩化物泉) - With magnesium, calcium and sodium, this type of thermal water heals cuts and burns due to the high salt content. It promotes skin hydration and helps you maintain body heat, perfect in winter.

Read more: Magnesium - The secret of Japanese longevity

Sulfate - Ryusan sen - This type of onsen is good for healing cuts and bruises, fighting chronic constipation and atherosclerosis. Water also provides moisture to the skin. Sodium sulfate helps with high blood pressure, while calcium sulfate helps with rheumatism.

Alkaline or sodium bicarbonate saline - Tansan suiso ensen - These hot springs feel thick and you feel a silky smoothness on your skin after showering. Alkaline water helps melt sebum, exfoliates the skin and removes blemishes. This onsen is a favorite among women who want flawless skin. We recommend the hinokamiso, ureshino, kitsuregawa and saksuikan onsen.

All types of saline waters help in healing cuts, burns and chronic skin disorders. Chloride and sodium bicarbonate sources are not recommended for people with kidney problems, high blood pressure, thyroiditis, or bloating.

Different types of onsen hot springs and their benefits

Sulfur - Iousen - (硫黄泉) – Sulfur onsen are mostly found near volcanic waters. Its distinctive smell and milky color is believed to help treat skin disorders and arthritis. Sulfur is rich in vitamin B1, B5, H and promotes metabolism and communication between nerve cells. Perfect for relieving rashes, itching, eczema, dandruff and warts as well as protecting the body against toxins.

Iron - Gantetsu sen - In these onsen the water is rust colored, it can be found in ikaho onsen. It helps the body's ability to retain heat, restores the body's iron levels, perfect for anemia, rheumatism and menstrual disorders. It also increases the quality of your blood, prevents stress, fatigue and improves skin tone. There are 2 types of water with iron, carbonated and melanterite. Don't be alarmed by the brown color of the water, this is iron concentration and not dirt.

Hydrogen/Carbonate - Tansansen (炭酸泉) - The carbonated waters create several fine bubbles that stick to the skin. It is said that this carbonated water improves blood circulation up to 5 times that of normal water. Bubbles also help remove waste from the body and detoxify. There is a beauty trend in Japan where people cleanse their skin with carbonated water.

Different types of onsen hot springs and their benefits

Special baths in Japanese hot springs

Aluminum - Ganaruminiumusen – This onsen has acidic properties, which provide sterilization effects. It has a bitter taste, said to be useful in the treatment of various skin conditions such as athlete's foot, rashes and dermatitis.

Acid - Sansei sen - These thermal waters provide an antibacterial effect, but it is not recommended for people with sensitive skin, as the acid can irritate it. Recommended for those who have sagging skin, want to treat rheumatism or make the skin more beautiful, as the acid eliminates dead skin cells.

Radiation - Hoshano sen – Yes, they are rare but there are spas with slightly radioactive waters that are not harmful to health. This slightly radioactive water is said to be good for arthritis, and some even claim to kill some tumors. In addition to improving metabolism, boosting immunity and healing the body's energy. Water, when inhaled, improves the body's antioxidant function, helps in anti-aging and prevents diseases. Just not super powers...

Carbon dioxide - Niisanka-tanso ensen - With about 100 milligrams of carbonic acid per kilogram, the water has a fine foam on the surface. They are rare, but they help against cuts, burns, arteriosclerosis and hypertension by expanding blood vessels.

Cold shower – Some onsen have icy pools that can help stimulate nerve endings, treat depression, release testosterone, stimulate the lymphatic system, fight infections, boost immunity, etc.

Different types of onsen hot springs and their benefits

Where to find an Onsen?

There are over 100,000 hot springs in Japan. They can be found at their own locations or in hotels, Ryokan and Pensions. There are also public and private Onsen that are not part of a hotel or residence.

Read also: Ryokan - The charming Japanese inns

Onsen varies from a natural location, in the middle of the forest to modern onsen with dozens (or hundreds) of baths. Onsen can be found even in large cities like Tokyo or small towns that we can barely find on the map.

However, the vast majority of hot springs are in the mountains and in the countryside. Japan has dozens of Onsen resorts like Atami and Hakone (near Tokyo). Each city may have dozens of Onsen baths.

Onsen - natural hot springs in Japan

To find an Onsen we recommend using Google Maps and searching for onsen [温泉], sento [銭湯], hot spring or the other terms we mentioned in the article.

And do you dare to go on an Onsen? Or are you ashamed? Leave your comment, and share with friends. Finally, I will leave you a video, we recommend also reading our article on different types of hot springs in the onsen.

Read also: How to map your destination in Japan with Google Maps

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