CHIGIRA JINSENTEI

Gunma Prefecture is home to three hot spring areas known as the "Three Famous Hot Springs of Jyoshu (Kusatsu Onsen, Ikaho Onsen, and Shima Onsen)", and one of them, Ikaho Onsen, is famous for a reddish-brown hot spring called "Kogane-no-Yu" (golden water). When it gushes out from the source, it is clear and colorless, but the iron contained in the water oxidizes when exposed to the air, giving it its mysterious color. "Onsen manju", an essential sweets in hot spring areas in Japan, is often brown in color, which is based on the color of this "Kogane-no-Yu" (golden water).
The name of the hot spring at "Kogane-no-Yu" is "Calcium, Sodium- Sulfate / Hydrogen carbonate / Chloride Springs". In simple words, it is a hot spring with the 3 characteristics of a Sulfate Springs, Hydrogen Carbonate Springs, and a Chloride Springs. The pH value is 6.4, neutral. Human skin is weakly acidic, and because the pH value is close to this, it is low-irritation and feels gentle on the skin.
First, the most notable dissolved substances in hot springs are the cation calcium ion and the anion sulfate ion, which are the most concentrated. These are combined to make a "Calcium-Sulfate Spring". In the old name of the spring, this spring was classified as a "Gypsum springs", and the sulfate ions are said to have the effect of closing cuts at the same time as stimulating the elasticity of the skin and preventing wrinkling. For this reason, it is also called "Hot springs for cuts" and "Hot springs for anti-aging". Calcium ions are also known as "Hot springs for beautiful skin" because of the effect of promoting the formation of stratum corneum.
It is also called "Hot springs for strokes" because it has a calming effect that relaxes the mind.

The second most concentrated anion is the hydrogen carbonate ion. This has the effect of improving blood circulation throughout the body.
When this ion is combined with calcium or magnesium cations, it becomes a "Calcium (Magnesium) - Hydrogen carbonate springs", or in the old name, a "Bicarbonate earth springs". The new name, Hydrogen carbonate springs, was classified into two types: "Bicarbonate earth springs" and "Sodium-Hydrogen carbonate springs".
Many of the "Calcium- Hydrogen carbonate springs (Bicarbonate earth springs)" contain carbon dioxide and iron, and have a calming effect due to the calcium and magnesium ions. They are good for Chronic skin diseases and Atopic dermatitis.
Also, like the aforementioned Sulfate springs, Hydrogen carbonate springs are well known as "Hot springs for beautiful skin". Hydrogen carbonate springs are also called "Hot springs for cool and refreshing" because the moisture from the skin becomes more active after bathing. Although hot springs are appreciated mainly during the cold season, this type of spring has many fans even during the hot summer months because of the refreshing feeling after bathing.

The third main component, anion chloride ions, has a heat-retaining effect that warms the body to the core. So-called "Sodium-Chloride springs" (old name for "Salt springs"), the salt content prevents sweat glands and delays the release of heat, making it difficult to cool down and is called "Hot springs for warmth". Chloride springs are also called "Hot springs for cuts" due to the sterilizing effect of the salt content.Also, the Chloride springs has a high moisturizing effect because of the coating effect of the salt pack.
As the abundance of indications suggests, this is an extremely high quality hot spring. Moreover, this hot spring is neither water added nor circulated and filtered, and is truly a "100% natural free-flowing hot spring water".
Note that sodium and hydrogen carbonate ions are also of interest. One of the qualifications for "hot spring" is that sodium hydrogen carbonate (baking soda) is an item listed as a salt according to the "Guidelines for Mineral Spring Analysis Methods", so the equivalent amount (mval/kg) of sodium ion and hydrogen carbonate ion is calculated, and the lower equivalent amount is multiplied by the molecular weight of sodium hydrogen carbonate (84.01). According to the Hot Spring Analysis Report, multiplying the lower equivalent of sodium ion (4.41 mval/kg) by 84.01 yields 370.88 mg/kg, which exceeds the standard value of 340 mg for "hot spring".
In addition, metasilicic acid, which is known as a natural moisturizer, is more than 3 times the standard value for qualifying as a "hot spring", moisturizing the skin. This makes it one of the "Hot springs for beautiful skin". Metaboric acid, which has a high cleansing effect, is also contained at more than the standard value for a hot spring.

Though it is a sub-characteristic, the iron（Ⅱ）ions that are the cause of the aforementioned color of the water contain as much as 7.23 mg/kg. 10 mg/kg or more qualifies it as a "hot spring", and 20 mg/kg or more would qualify it as an "Iron-containing spring", which is slightly less, but still has hidden effects. It warms the body well and is said to be good for Anemia, Menopausal disorders, and Menstrual disorders, and is good for women.
The 172 mg/kg of free carbon dioxide also should be noted. 250 mg/kg or more qualifies as a "hot spring", and 1,000 mg/kg or more as a "Carbon dioxide spring", which promotes blood circulation by expanding blood vessels. By the way, popular carbon dioxide bath salts contain 40 to 100 mg/kg of carbon dioxide, but this hot spring is several times higher than that. However, because of the high temperature of the spring, bubbles cannot be confirmed.

In addition, indications for drinking include biliary tract disease, dyslipidemia (high cholesterol), constipation, gastroduodenal pickle, reflux esophagitis, impaired glucose tolerance (diabetes), hyperuricemia (gout), and atrophic gastritis, but unfortunately, the inn has not applied for a health department permission to drink it at this time.

Ikaho Onsen is one of the most popular hot spring areas in the Kanto region, located halfway up Mt. Haruna in Gunma Prefecture, and has a rich history and tradition from the Manyo Period (710-794). It is said that the hot spring water was discovered either 1,900 or 1,300 years ago. "Chigira Jinsentei", established over 500 years ago, is one of the oldest ryokan in the Ikaho Onsen area. The symbol of Ikaho is the 365-step Ishidan Street (stone stairway). When you climb to the top of the stone steps, near the Kawaga Bridge, you will find the source of the Ikaho Onsen "Kogane-no-Yu", and next to it, surrounded by stone walls, is the site of the "Chigira Motoyashiki". During the Tenbun era (1532-1555) of the Sengoku period, when Uesugi Norimasa, the nominal Kanto governor, was ruling the area, the Chigira clan was already in charge of the hot spring source. In the Edo period (1603-1867), the "Komaguchi Right Holders Association" was created to own the rights to the hot springs, which continues to this day, and the "Chigira Jinsentei" continued to be a central member of the association. The "Komaguchi Right Holders" (source owners) means those who own "Komaguchi", which is a hot spring piping system, and who each own a certain amount of hot spring water. Today, the 9 owners of the ryokan have formed an association to protect the centuries-old reddish brown "Kogane-no-Yu" (golden water) by stipulating strict rules for its use. Of these 9 ryokan, "Chigira Jinsentei" is said to have the largest amount of hot spring water per guest. Today, "Chigira Jinsentei" stands halfway up the stone staircase street and is also an inn connected to Tokutomi Roka (1868-1927), a great writer of the Meiji and Taisho eras. Roka loved Ikaho, especially this "Chigira Jinsentei" inn, and stayed here regularly, and even passed away here. His masterpiece, "Fujoki (The Cuckoo)" which is based on this inn was also set in this inn. Also, the poet Akiko Yosano and the great writer Junichiro Tanizaki are known to have visited the inn. Today, the inn is also known as the Imperial Family's official lodging. Despite its history and traditions, the inn is supported by a wide range of customers, with rooms available at reasonable rates, as well as rooms with the popular open-air bath. The inn has a large number of baths: large public baths for men and women + indoor baths, large public baths for men and women (Ninoyu and Takiyu), and 4 private baths that can be used free of charge. And the most wonderful thing about this inn is that the "Kogane-no-Yu" (golden water) is so abundant than other inns envy, and can be experienced as 100% natural free-flowing hot spring water. At present, there are around 50 onsen ryokan in Ikaho Onsen, but it is said that only about half of them use "Kogane-no-yu" (golden water). 9 of the right holders (source owners) must be splitting the hot spring with them. Note that "Chigira Jinsentei" does not share its hot spring water with any other ryokan. A regular customer told us that the hot springs here are "richer" than anywhere else. (Jin)
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