ARIMAKAN

Kaminoyama Onsen, where “Arimakan” is located, is an area that uses a “centralized management” system for its hot springs.
The “centralized management” system collects hot spring water from each source well in a storage tank, where it is mixed and stored before being supplied to each facility. This system efficiently utilizes hot spring sources and stabilizes the quantity and quality of the supply.
“Arimakan” draws hot spring water from three sources that are generally the same in quality, known as Kaminoyama Sources No. 1, No. 2, and No. 3.
Each of the three sources has a different temperature, so they are making efforts to protect the limited hot spring resources for the future by resting the source well with the highest temperature during the summer when the outside temperatures are high.
Arimakan originally owned its own hot spring source well, but in the interest of conserving hot spring resources, it has since agreed to a system in which the sources are collectively owned and managed by the entire hot spring area.
The Hot Spring Analysis Report for the Arimakan shows data from a mixture of these three sources.
The temperature of the spring is slightly high at 62.8°C, but by the time the water is distributed to the bathtubs at each facility, the temperature of the spring has dropped to a suitable level, so it can be said to be an ideal spring temperature.

The pH (hydrogen ion concentration) is 7.6 (Weakly alkaline).
Human skin is naturally slightly acidic (pH 4.5–6.0), so soaking in a weakly alkaline hot spring helps remove old dead skin cells from the skin’s surface, leaving it feeling smooth. After bathing, your skin may feel refreshed and renewed.

The name of the spring quality is “Sodium, Calcium - Chloride / Sulfate springs”.
In the old name of the spring, it is a “Gypsum - Weakly Salt spring”.
In other words, the spring has two characteristics: Sodium - Chloride spring (old name: Salt spring) and Calcium - Sulfate spring (old name: Gypsum spring).
The five common indications of the “Chloride spring” and “Sulfate spring” are Cuts, Peripheral circulatory disturbance, Sensitivity to cold, Depression, and Dry skin.

First, let's start with the “Sodium - Chloride spring”, which is salty when drunk because salt is its main component.
Its salt content has a bactericidal effect and is considered beneficial for Cuts and burns, and thus the “Chloride spring” is called “Hot spring for cuts”. When you soak in the hot spring, the salt coats the body and forms a thin film on the skin after bathing. This helps reduce heat loss and allows the warming effect to last longer. Therefore, the blood circulation improves, and it is said to be good for Peripheral circulatory disturbances and Sensitivity to cold, and it is also called “Hot spring for warmth”.
In addition, the lasting warming effect is said to be good for Depression by reducing the secretion of stress hormones, balancing the autonomic nervous system, and promoting a sense of mental stability.
The coating effects, such as the salt pack, also strengthen the moisturizing effect, which is helpful for Dry skin.

Next, the main feature of the “Calcium - Sulfate spring” is probably that it is called “Hot springs for beautiful skin” because of the combination of calcium ions, which promote skin regeneration, and sulfate ions, which increase skin elasticity and prevent wrinkles and sagging. In other words, it promotes collagen production, supports skin renewal, and stimulates skin metabolism. It is also called “Hot springs for rejuvenation” because it is expected to have an anti-aging effect on the skin, helping the skin feel firm and moisturized.
Sulfate ions also have antibacterial and anti-inflammatory effects, and thus relieve pain and inflammation such as Cuts, arthritis, and muscle pain. Therefore, Sulfate springs, like Chloride springs, are also called “Hot springs for cuts”.
Calcium ions also have the effect of regulating the contraction and dilation of blood vessels, contributing to the stabilization of blood pressure. In other words, by stabilizing blood vessels, blood circulation in peripheral areas (e.g., hands and feet) where blood flow tends to be sluggish is promoted, and Peripheral circulatory disturbance and Sensitivity to cold can be improved. This circulation-promoting effect also raises core body temperature and helps regulate the autonomic nervous system, which may reduce stress, promote mental stability, and help relieve Depression. It also helps replenish moisture in Dry skin, making it beneficial for skin dryness.

Note the components that do not appear in the name of the spring.
The Fluoride ions are present at 4.2 mg/kg per kg of spring water, which is more than twice the standard value (2 mg) for hot spring qualification. Fluoride is well known for its role in helping prevent tooth decay. In hot spring water, it is also considered to have bactericidal properties, particularly by inhibiting the growth of bacteria, and may therefore help in the treatment and prevention of skin conditions.
It may also help moisturize the skin and promote skin metabolism. Trace amounts of fluoride absorbed by the skin may support skin renewal and help relieve dryness and inflammation.

The non-dissociated component Metaboric acid is present at 12.0 mg/kg of hot spring water. This is more than twice the standard value (5 mg/kg) required to qualify as a hot spring. This component is said to have a purifying effect, which may help prevent acne.

Metasilicic acid is also present at 56.6 mg/kg of hot spring water, exceeding the standard value of 50 mg/kg. It is often described as a natural moisturizing component. In other words, its high moisture-retaining properties may help the skin retain moisture after old dead skin cells have been removed by the weakly alkaline hot spring water.

In addition, another great attraction of this inn is that it is officially recognized by the public health department as a drinking spring. Permission to drink hot spring water requires meeting very strict hygiene standards, making facilities where hot spring water is officially approved for drinking quite rare.
In some parts of Europe and the U.S., drinking mineral spring water is even practiced as a form of medical treatment, reflecting its long-recognized health benefits. However, when drinking the hot spring water, be careful not to exceed the recommended daily limit (100–150 ml at a time and 200–500 ml per day).
The indications for drinking this hot spring by spring quality, which are common to both “Chloride spring” and “Sulfate spring”, are Constipation. The sodium chloride stimulates the intestinal wall, and the calcium ions stabilize intestinal movement, allowing stool to pass smoothly through the intestines.
In addition, Atrophic gastritis is one of the indications for drinking “Chloride spring” by spring quality. Sodium chloride stimulates the gastric mucosa and promotes gastric acid secretion, while also protecting the gastric mucosa.
Other indications for drinking “Sulfate spring” by spring quality include Biliary dysfunction (sulfate ions promote bile secretion) and Hypercholesterolemia (calcium ions balance blood lipids).

The exfoliating effect of the weakly alkaline components and the skin-revitalizing effect of the sulfate spring meet the criteria for “Hot springs for beautiful skin”. In addition, the moisturizing effect of the protective coating formed by the chloride spring and the purifying effect of metaboric acid further demonstrate the outstanding qualities of the hot spring water at Kaminoyama Onsen.
At “Arimakan”, the large public baths and some of the private baths use 100% natural free-flowing hot spring water, while the other baths use a circulating filtration system, with fresh hot spring water continuously added and the bathwater disinfected with chlorine.
In baths shared by many guests, rinsing the body before entering the bath is essential bathing etiquette. Even so, circulating and filtering the hot spring water, together with chlorine disinfection, is necessary to keep the bathwater clean and hygienic.
Some hot spring enthusiasts criticize circulating systems for reducing the concentration of hot spring components. However, the source water at Kaminoyama Onsen contains a total of 2,389 mg/kg of cations, anions, and non-dissociated components (total dissolved substances excluding gaseous components).
Keep in mind that this represents an impressive 16 to 24 times the concentration of active components found in a well-known commercial bath additive.

The public bath with free-flowing hot spring bath and bedrock bath are located on the first floor and in the basement, switching between men and women according to the time of the day.
The rooftop open-air bath is a symbol of the inn's popularity and offers a panoramic view of the city of Kaminoyama Onsen and the Zao mountain range.

They are quick to do what makes their customers happy. Such a basic attitude seems to be the motto here.
Not only are the hot springs of high quality, but the baths themselves are rich in variety, including a private bath inspired by the limestone terraces of “Hierapolis Pamukkale” a World Heritage Site in Turkey, the barrier-free private bath “Yawaragi”, and a standing private bath.
The inn's popular rooftop open-air bath changes its appearance to a private open-air bath at night.
Thus, there are five private baths in total.

It is suitable for a celebration or anniversary trip, or just a fun vacation among friends. The inn is full of fun and memorable elements.
In addition, one of the joys of a ryokan is the food. The inn's style is to insist in-room service. Taking the food to each room is time-consuming, but for those who prefer to enjoy their meals in the comfort of their own guest room, this ryokan dares to maintain the "in-room meal" policy.

The atmosphere inside the inn, which is filled with a cheerful ambience in a quiet and remote Tohoku-like atmosphere, is comfortable and allows you to relax without any worries. Considering the room rate, you will be astonished at the cost-performance ratio, and the fact that you can relax so much at a price in the 10,000-yen range is a sign of the inn's conscientiousness. Travel Journal