When you visit hot spring areas in Japan, you'll encounter terms like 'Simple Hot Spring,' 'Chloride Spring,' and 'Sulfur Spring.' These terms represent the 'water quality' of the hot spring. 'What is water quality?' 'How are they different?' 'Which one suits me best?'
In this article, we will clearly explain the 10 types of hot spring water qualities in Japan for beginners. We'll focus on what you actually feel when you enter the hot spring, including appearance, smell, texture, and benefits.
What is Water Quality? Basic Knowledge
Definition of Water Quality
Water quality refers to the type classified by the types and amounts of chemical components contained in the hot spring. In Japan, hot springs are classified into 10 types of water qualities (11 types in the old classification).
Why is Water Quality Important?
The expected health benefits vary depending on the water quality. The appearance, smell, and texture are completely different. Moreover, people have preferences for certain water qualities. I also make it a point to research the water quality of hot springs I plan to visit. Knowing the water quality can greatly enrich your hot spring experience.
Where Can You Check the Water Quality?
All hot spring facilities display an official document called the 'Hot Spring Analysis Report.' It lists the water quality, components, temperature, and more. It is often also mentioned on facility signs and brochures.
1. Simple Hot Spring: Most Common and Gentle on the Skin
Characteristics
A hot spring that does not reach a certain level of components. However, the temperature is 25°C or higher. The color is clear (colorless), the smell is odorless, and the texture is smooth and gentle on the skin. The pH is neutral to slightly alkaline.
The name 'Simple' does not mean the components are 'simple.' It is named so because the total amount of components does not reach the specified level.
Appeal of Simple Hot Springs
They are low in stimulation, suitable for babies and children. Safe for sensitive skin and gentle for the elderly. They have no peculiarities, making them enjoyable for everyone.
They are effective for fatigue recovery, health promotion, stress relief, insomnia improvement, and autonomic nervous system regulation.
Gero Onsen (Gifu), Kinugawa Onsen (Tochigi), and Towadako Onsen (Aomori) are famous. The first hot spring I visited was also a simple hot spring. Its gentle touch taught me the wonders of hot springs.
Recommended for hot spring beginners, those with sensitive skin, children, the elderly, and those who prefer non-peculiar hot springs.
2. Chloride Spring: Excellent Heat Retention
Characteristics
A hot spring with salt (sodium ions, chloride ions) as the main component. The color ranges from clear (colorless) to yellowish-brown, the smell is almost odorless, and the texture is moist and slightly sticky. It tastes salty if you lick it.
Appeal of Chloride Springs
Also known as 'Heat Bath.' It retains heat well, keeping your body warm even after bathing. This is because the salt forms a film on the skin. They are often found in hot spring areas along the coast.
They are effective for improving cold sensitivity, peripheral circulation disorders, joint pain, muscle pain, and cuts and burns (after bathing).
Atami Onsen (Shizuoka), Kaike Onsen (Tottori), and Wakura Onsen (Ishikawa) are famous. I also prefer visiting chloride springs in winter. The sensation of staying warm after bathing is unique to this water quality.
Recommended for those with cold sensitivity, those who easily get chilled, during cold seasons, and those seeking heat retention effects.
3. Bicarbonate Spring: Beauty Bath
Characteristics
A hot spring with bicarbonate ions as the main component. The color ranges from clear to milky white, the smell is almost odorless, and the texture is slippery and smooth. Also known as 'Beauty Bath' or 'Beauty Skin Bath.'
Appeal of Bicarbonate Springs
They soften the surface of the skin, removing old keratin. The skin becomes smooth, and the texture after bathing is excellent. They act like natural soap.
However, as they can cause dryness after bathing, it is recommended to apply moisturizing cream.
They are effective for beauty skin effects, cuts, burns, and chronic skin diseases.
Ureshino Onsen (Saga), Hinokami Onsen (Shimane), and Ryujin Onsen (Wakayama) are famous as Japan's top three beauty baths. When I entered Ureshino Onsen, I was amazed by the slippery feel and the smoothness of my skin after bathing. I understood why it's called 'Beauty Bath.'
Recommended for those aiming for beautiful skin, those who want smooth skin, and women.
4. Sulfate Spring: Healing Bath
Characteristics
A hot spring with sulfate ions as the main component. The color ranges from clear to milky white, the smell is almost odorless, and the texture is smooth.
Appeal of Sulfate Springs
Also known as 'Healing Bath,' it has been used for treating cuts and burns since ancient times. It dilates blood vessels and improves blood flow.
They are effective for arteriosclerosis, high blood pressure, cuts, burns, and chronic skin diseases.
Hoshi Onsen (Gunma) and Tsukioka Onsen (Niigata) are famous.
5. Carbon Dioxide Spring: Heart Bath
Characteristics
A hot spring containing a certain amount of free carbon dioxide. The color is clear, the smell is almost odorless, and the texture has carbon dioxide bubbles adhering to the skin. Also known as 'Soda Bath' or 'Bubble Bath.'
Appeal of Carbon Dioxide Springs
When you bathe, fine bubbles adhere to your skin. This sight is impressive. Carbon dioxide is absorbed through the skin, dilating blood vessels. Known as 'Heart Bath,' it promotes circulation without putting a burden on the heart.
They are effective for high blood pressure, arteriosclerosis, heart disease, and cold sensitivity.
Nagayu Onsen (Oita) and Arima Onsen's Carbonated Spring (Hyogo) are famous. When I first entered a carbon dioxide spring, I was amazed by the sight of bubbles all over my body. I experienced the mysterious sensation of feeling warm despite the lukewarm temperature.
It is a rare water quality in Japan, and if you find one, you should definitely try it.
6. Sulfur Spring: The Quintessential Hot Spring
Characteristics
A hot spring containing sulfur. The color ranges from milky white to greenish-white, the smell is of sulfur (like rotten eggs), and the texture is slippery and smooth.
Appeal of Sulfur Springs
This is the water quality where you can most feel 'I've come to a hot spring!' The unique sulfur smell and milky white water offer a quintessential hot spring experience.
They have strong antibacterial effects and blood vessel dilation properties. They are effective for chronic skin diseases, chronic gynecological diseases, diabetes, and high blood pressure.
Kusatsu Onsen (Gunma), Noboribetsu Onsen (Hokkaido), and Hakone Onsen (Kanagawa) are famous. I love sulfur springs. That unique smell gives me the feeling of 'I've come to a hot spring.' The luxury of soaking in milky white water never gets old.
However, some people may not like the smell. Metal accessories may discolor, so remove them before bathing.
7. Acidic Spring: Strong Antibacterial Effect
Characteristics
A strongly acidic hot spring with a pH below 3. The color ranges from clear to milky white, the smell may have a sulfur odor, and the texture has a tingling sensation.
Appeal of Acidic Springs
They have a strong antibacterial effect due to their strong acidity. They are effective for athlete's foot, atopic dermatitis, and chronic skin diseases.
However, due to their strong stimulation, people with sensitive skin should be cautious. It is recommended to rinse with fresh water after bathing.
Kusatsu Onsen (Gunma), Zao Onsen (Yamagata), and Tamagawa Onsen (Akita) are famous. When I entered Tamagawa Onsen, I was surprised by the tingling sensation. The feeling of the skin tightening is unique to this water quality.
8. Iron-Containing Spring: Reddish-Brown Hot Spring
Characteristics
A hot spring containing a certain amount of iron ions. The color ranges from reddish-brown to yellowish-brown, the smell is metallic, and the texture is normal.
Appeal of Iron-Containing Springs
When exposed to air, it oxidizes and turns reddish-brown. Watching this color change process is also interesting.
They are believed to be effective for anemia and menopausal disorders.
Arima Onsen's Kinsen (Hyogo) and Naruko Onsen (Miyagi) are famous.
It is a relatively rare water quality in Japan.
9. Iodine-Containing Spring: Contains Iodine
Characteristics
A hot spring containing a certain amount of iodine. The color ranges from clear to yellowish-brown, the smell is of iodine, and the texture is normal.
Appeal of Iodine-Containing Springs
They are believed to be effective for hypercholesterolemia.
They are often found in hot springs in Chiba Prefecture.
It is a relatively rare water quality in Japan.
10. Radioactive Spring: Contains Radon
Characteristics
A hot spring containing a certain amount of radon. The color is clear, the smell is odorless, and the texture is normal. Also known as 'Radium Spring.'
Appeal of Radioactive Springs
Although it is called 'radioactive,' it does not have dangerous levels of radioactivity. It only contains trace amounts of radon.
They are believed to be effective for gout, rheumatoid arthritis, and ankylosing spondylitis.
Misasa Onsen (Tottori) and Masutomi Onsen (Yamanashi) are famous.
How to Choose Water Quality
For Beginners
Start with a simple hot spring. It is low in stimulation and enjoyable for everyone.
If You Want a Quintessential Hot Spring Experience
Sulfur springs are recommended. The milky white water and sulfur smell will give you the feeling of 'I've come to a hot spring!'
If You Seek Beautiful Skin
Bicarbonate springs are ideal. Experience why they are called 'Beauty Bath.'
If You Have Cold Sensitivity
Chloride springs are effective. They have excellent heat retention and prevent getting chilled.
If You Want a Unique Experience
Look for carbon dioxide springs. They are a rare water quality in Japan, and the experience of bubbles adhering to your skin is impressive.
Conclusion: Knowing Water Quality Makes Hot Springs More Enjoyable
By knowing the water quality of hot springs, your experience becomes much richer. Each water quality has its own characteristics, benefits, and appeal.
I have experienced various water qualities while visiting hot springs across Japan. The gentleness of simple hot springs, the heat retention of chloride springs, the beauty effects of bicarbonate springs, the quintessential experience of sulfur springs, and the uniqueness of carbon dioxide springs. All of them are wonderful.
When you visit Japan, be sure to experience hot springs with various water qualities. Find your favorite water quality. That is the first step to deeply enjoying hot springs.
