Ryokan Kounoyu

The hot spring at Ryokan Kounoyu uses its own private source located on the property. This means the distance from the source well to the bath is very short. Drawn from 300 meters underground, the spring water is rich in beneficial minerals, and the environment allows guests to experience its freshness without degradation.
The spring water emerges at a temperature of 60.5℃ . To maintain a comfortable bathing temperature (40‒42℃), water is not added as much as possible. Instead, the temperature is adjusted using heat exchangers and by controlling the volume of water flowing into the baths. While most modern hot spring facilities manage water temperature through computerized systems, here, it is done by hand. This dedication to preserving the hot spring’s quality is truly admirable. According to the Hot Spring Analysis Reports, the dissolved substances (excluding gaseous substances), which are the active components of the hot spring, are 1,180 mg/kg. Since this exceeds 1,000 mg/kg, the spring qualifies as a “saline spring”, and the main components are listed in the spring quality name. That spring quality name is: Sodium, Calcium‒Hydrogen Carbonate/Sulfate/Chloride Spring. Yes, it’s a long name, but it serves as proof of the variety of characteristics of the hot spring. Simply put, it’s a unique blend of 3 spring qualities: hydrogen carbonate spring, sulfate spring, and chloride spring. Let’s look at each in more detail. 1. Hydrogen Carbonate Spring When sodium ions, the most abundant cation, and hydrogen carbonate ions, the most abundant anion, are combined, the result is a Sodium‒Hydrogen Carbonate Spring (formerly known as “Sodium Bicarbonate Spring”). Hydrogen carbonate softens the outer layer of the skin, making it easier to remove dead skin cells. This leaves the skin smooth and is why it’s often called “Hot springs for beautiful skin” with cleansing effect. In addition, it is also called “Hot springs for refreshing” or “Hot springs for cooling effect”, because the skin's protective power is weakened by the reduction of sebum, making it easier for moisture on the surface of the skin to evaporate, and bathing in it, especially during hot weather, provides a refreshing feeling afterwards. Hydrogen carbonate ion also enhances the cleansing effect on the skin and promotes disinfecting and sterilizing action on wounds, supporting healing for cuts. It also promotes the removal of dead skin cells while retaining moisture, which helps with dry skin as well. Furthermore, the carbon dioxide (CO₂) contained in the product is absorbed into the body through the skin, dilating peripheral blood vessels and improving blood flow, which has an effect on peripheral circulatory disturbance. As blood flow increases, symptoms of sensitivity to cold are alleviated.

2. Sulfate Spring When calcium ions, the second most abundant cation, and sulfate ions, the second most abundant anion, are combined, the result is a Calcium‒Sulfate Spring (formerly known as “Gypsum Spring”). This sulfate spring is called “Hot springs for anti-aging” because of its skin reviving and wrinkle stretching effects , and like “Sodium - Hydrogen carbonate spring (Sodium bicarbonate spring)”, it is also called “Hot springs for beautiful skin”. Furthermore, it is also known as “Hot springs for cuts” because of its ability to revive the skin. In addition, calcium ions have the effect of adjusting the contraction and dilation of blood vessels, stabilizing blood pressure and having a calming effect, and sulfate ions have the effect of dilating blood vessels, making them good for hypertension and arteriosclerosis, and “Calcium‒Sulfate springs” are also called “Hot springs for strokes ”. The indications by spring quality of sulfate springs include the same 4 items as hydrogen carbonate springs (cuts, peripheral circulatory disturbance, sensitivity to cold, dry skin ), with the addition of depression.

3. Chloride Spring The third spring quality is the Sodium‒Chloride Spring (formerly known as “Weak Salt Spring”). Salt forms a thin layer over the skin’s sweat glands, preventing evaporation of sweat and helping the body retain warmth after bathing. Because of this effect, it is commonly referred to as “Hot springs for warmth ”. The long-lasting heat-retention effect promotes balance in the autonomic nervous system and contributes to emotional stability. Additionally, by raising the body temperature, it may suppress the secretion of stress hormones and improve mood, showing potential benefits for depression . Furthermore, because it coats the skin, it works excellently as “Hot springs for finishing touch” after bathing in “Hot springs for beautiful skin”, locking in moisture and enhancing hydration. Due to the salt’s bactericidal properties, it is also known as “Hot springs for cuts”. In summary, the indications by spring quality of chloride springs match those of sulfate springs: cuts, peripheral circulatory disturbance, sensitivity to cold, dry skin and depression .
In addition to having the benefits of all 3 spring qualities, this hot spring has a neutral pH of 6.4, making it gentle and low-irritant—perfect for sensitive skin. Let’s take a closer look at the sodium ions and hydrogen carbonate ions. When their combined milliequivalent percentage exceeds 80%, the water is said to have a “silky-smooth” texture. This spring contains 52.96% sodium ions + 37.01% hydrogen carbonate ions, totaling 89.97%, so guests will truly feel the smoothness when they bathe. Furthermore, the amount of sodium hydrogen carbonate (also known as sodium bicarbonate)—a key indicator of hot spring quality—is 397 mg/kg, which surpasses the legal threshold of 340 mg/kg to qualify as an official hot spring. The hot spring also contains 251.4 mg/kg of metasilicic acid, a non-dissociating moisturizing component. This amount is more than 5 times the standard value for hot spring, and in this respect can also be called “Hot springs for beautiful skin”. Additionally, the spring contains 9.7 mg/kg of metaboric acid, which is known for its strong cleansing effects. This exceeds the 5 mg/kg threshold to qualify as a hot spring, and had it surpassed 10 mg/kg, it could be called “Hot springs for beautiful skin”. What makes this experience even more special is that the spring water is delivered directly from the source without circulation—a luxurious kakenagashi style—allowing guests to fully feel the natural benefits of the spring on their skin. One of the reasons this inn is so beloved is its use of an abundant private hot spring source, offering guests 3 types of open-air baths: public open-air baths, private open-air baths, and guest room open-air baths that can be enjoyed at any time of day, at your own pace.

Kurokawa Onsen has become one of the most popular hot spring areas not only in Kumamoto Prefecture and Kyushu, but also in Japan. The hot spring town stretches along the Tanoharu River in a valley, and is mainly made up of small-scale inns with 30 or fewer guest rooms. The exterior of the inns, all with clay walls and kawara tiled roofs, combined with the surrounding countryside, creates an atmosphere that is truly worthy of being called the "Japanese countryside". Many tourists enjoy strolling through the hot spring town on weekdays and weekends, and it has become a typical sight in this town.
Located the center of this hot spring area are "Jizo-do" and "Jizo-yu" (the first site of hot spring gushing in Kurokawa). Next to these is the "Ryokan Kounoyu", which is the detached building of the "Fumoto Ryokan".
The small inn is located on a hill about 1 km from the center of the hot spring area, about a 10 min. walk away, and was originally run by a different company. In 2002, Fumoto Ryokan purchased the inn and reopened it. The inn is popular among travelers who want to enjoy the atmosphere of Kurokawa Onsen in a quieter setting, as there are no other lodging facilities nearby, while maintaining the "Kurokawa-ness" of the rural atmosphere and sense of oneness with nature. The buildings are scattered among the trees and look as if they blend in with the greenery. In the fall, the autumn leaves add color and create a more elegant atmosphere.
The inns in Kurokawa Onsen are not relatively large buildings. Some inns offer unique baths, such as vast open-air baths with large rocks or cave baths, to entertain guests. Another feature is the large number of family baths (private baths). The quiet environment is wonderful due to its location a little away from the central area of Kurokawa, but this inn offers a higher grade of relaxation.
This inn is a "detached" style inn, approached from the front building through a corridor with access to the outside air, and is luxurious in that it has a "guest room open-air bath" with "free-flowing hot spring water". The wooden architecture and rustic furniture and furnishings are typical of Kurokawa Onsen, rather than going the route of modern designer ryokan, and the hotel has all the elements that make it popular with people of all ages. Many guests use the inn for anniversary events such as wedding anniversaries and birthdays. The reason for this must be the well-balanced mixture of a somehow relaxing atmosphere and a high-quality, extraordinary atmosphere.
Travel Journal