FUMOTO RYOKAN

Private Open-air Bath “Fumoto-no-Yu”

Kyushu > Kumamoto > Kurokawa Onsen

Hot spring inn with 100% natural free-flowing hot spring water, offering a wide selection of open-air, private, and in-room open-air baths.

Fumoto Ryokan

ふもと旅館

Kawabata-dori, Kurokawa Onsen, Minami-Oguni machi, Aso-gun, Kumamoto Prefecture, 869-2402, JAPAN
Phone:+81-(0)967-44-0918

Spring Quality

Sodium, Calcium – Hydrogen carbonate / Sulfate / Chloride springs

ナトリウム・カルシウム―炭酸水素塩・硫酸塩・塩化物泉

(Hypotonic, Neutral, High temperature spring)

Excellent 100% natural free-flowing hot spring
with multiple properties —
for beautiful skin, hydration, warmth, and healing

Hot springs are believed to form when rainwater or snowmelt seeps underground, or when ancient seawater becomes trapped deep within the earth. Heated by magma or the earthʼs internal heat, this water dissolves minerals from underground rocks and slowly rises to the surface over years—or even tens of thousands of years.

Onsen Components

Cation Graphs

Sodium Ion
160.9 mg/kg
52.96mval%

Helps improve dry skin through its moisturizing effect
Relieves muscle tension and alleviates pain
Promotes blood circulation, helping to reduce sensitivity to cold
Boosts metabolism and supports detoxification
Calcium Ion
54.0 mg/kg
20.39mval%

Supports the formation and regeneration of the skin barrier
Helps soothe pain and inflammation
Regulates the contraction and dilation of blood vessels
Strengthens the skin’s barrier function

Anion Graphs

Hydrogen Carbonate Ion
288.8 mg/kg
37.01mval%

Helps remove old keratin and excess sebum for smoother skin
Leaves the skin feeling fresh and refreshed after bathing
Washes away impurities, keeping the skin clean
Helps improve circulation by dilating blood vessels
The main component of Hydrogen carbonate springs, known as one of the “Hot springs for beautiful skin
Sulfate Ion
197.2 mg/kg
32.10mval%

Dilates blood vessels and promotes circulation to the extremities
The warming effect from increased blood flow helps regulate the autonomic nervous system
Promotes skin metabolism, improving firmness and elasticity
Supports recovery from skin issues such as dry skin and minor cuts
The main component of Sulfate springs, known as one of the “Hot springs for beautiful skin
Chloride Ion
138.7mg/kg
30.59mval%

Salt’s bactericidal effect helps treat minor cuts and wounds
Salt helps block sweat glands, enhancing heat retention
Improved heat retention contributes to balancing the autonomic nervous system
A salt coating helps promote moisture retention
Sodium Hydrogen Carbonate
397mg/kg
Exceeds the hot spring standard value of 340 mg/kg

Acts like a natural soap, emulsifying dead skin cells and sebum for gentle cleansing
Leaves the skin smooth and well-hydrated after bathing
Provides a refreshing, clean feeling after bathing
A cleansing-type onsen known as “Hot springs for beautiful skin

This component is formed by the combination of the cation Sodium ions (160.9 mg/kg, 7.00 mval, 52.96 mval%) and the anion Hydrogen carbonate ions (288.8 mg/kg, 4.73 mval, 37.01 mval%). When present at 340 mg/kg or higher, it qualifies as a hot spring component. Commonly known as baking soda, it emulsifies sebum (breaking oils into fine particles so they mix with water), making it easier to wash away. This process softens dead skin cells and leaves the skin smooth and refined. It is a key component that characterizes “Hot springs for beautiful skin”.

Non-dissociated components Graphs

*The bars for Metasilicic acid 50 mg/kg    and Metaboric acid 5 mg/kg    represent the qualification criteria for hot springs. The number of bars indicates values such as “more than XX times the hot spring standard” or “about XX times the hot spring standard”.

Metasilicic Acid
251.4 mg/kg

Natural moisturizing component
More than 5 times the hot spring standard (50 mg/kg)
Metaboric Acid
9.7 mg/kg

Helps keep the skin clean
About 2 times the hot spring standard (5 mg/kg)

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Total Dissolved Substances

(excluding gaseous)


1,180 mg/kg

amazing.png About 8-11 times more components than standard bath additives!

Bath additives

 

Hydrogen Ion
Concentration

pH 6.4
Neutral

Hydrogen Ion Concentration

In harmony with the skin’s natural pH —
gentle hot spring watersn

Spring Temperature

60.5


Maintained at a comfortable temperature by adjusting the water flow

Color of water /
Smell of water

Color of water

Colorless to Pale green

Smell of water

Faint hydrogen sulfide odor


Volume of water

100~150 liters per minute
(Private hot spring source / Mechanically pumped)

Volume of hot spring water

Hot spring water usage per person (spring discharge / maximum capacity)

→ 100~150 / 50 guests = 2~3 liters / per minute

*To meet the requirements for kakenagashi (flowing directly from the source),
at least 1 liter of hot spring water per minute per bather
is required for proper bath management


Status of Source Utilization

Water added Heated Disinfected Circulated Bath additives
No No No No No

*All baths are supplied with 100% natural free-flowing hot spring water

“Tachi-yu” Private Bath

Private Bath “Tachi-yu”
It is the largest of the private baths. The depth increases as you move from the front to the back, reaching a maximum depth of 150 centimeters, and you can stretch your legs by holding onto the wooden pillar in the center. Stretching your arms and legs to the fullest in a natural, comfortable posture puts no strain on your back or knees.

Skin Feeling Gauge

Skin Feeling Gauge

Ideal for:

People seeking beautiful skin

People seeking
beautiful skin

People with dry skin

People with dry skin

People concerned about minor cuts

People concerned
about
minor cuts

People feeling stressed

People feeling
stressed

People sensitive to cold

People sensitive
to cold

People seeking a refreshing sensation after bathing

People seeking
a refreshing
sensation
after bathing

Indications by Spring Quality
(for bathing)

(Indications specific to this spring type)
  • Cuts
  • Peripheral circulatory disturbance
  • Sensitivity to cold
  • Depression
  • Dry skin

General Indications (for bathing)

Chronic pains or stiffness of muscles or joints (chronic phase of rheumatoid arthritis, osteoarthritis, lower back pains, nerve pains, frozen shoulder, bruises, sprains, etc.), Muscle stiffness in motor paralysis, Sensitivity to cold, Peripheral circulatory disturbance, Gastrointestinal hypofunction (slow digestion, intestinal gas formation, etc.) Mild hypertension, Impaired glucose tolerance (diabetes), Mild hypercholesterolemia, Mild asthma or Emphysema, Hemorrhoidal pains, Autonomic instability, Various symptoms from stress (sleep disorders, depression, etc.), Restorative phase from illness, Recovery from fatigue, Health promotions

General Contraindications (for bathing)

Active stage of diseases (especially when fever is accompanied), Active tuberculosis, Advanced malignant tumor or the case of significant debility involving severe anemia, Severe cardiac or lung diseases involving suffocation feelings with a little movement, Severe kidney diseases involving edema, Gastrointestinal bleeding, When bleeding is visible, Acute exacerbation stage of chronic diseases
*There are no general indications or contraindications for drinking.


Onsen Power Chart

Large public baths / Open-air baths

Onsen Power Chart

new source_water


Open-air bath “Momiji-no-Yu”

Open-air bath “Momiji-no-Yu”
Bathing while listening to the murmuring of the Tanohara River flowing below the open-air bath provides a strong therapeutic effect of a change in environment.

Keywords of this Onsen

Keywords of this Onsen

Cuts・・・ Cleanses the wound area, promotes tissue regeneration, helps disinfect.
Peripheral circulatory disturbance・・・ Regulates metabolism, dilates blood vessels, retains heat and promotes peripheral blood flow.
Sensitivity to cold・・・ Conditions the skin and allows heat to penetrate, dilates blood vessels and warms the body to the core, seals in warmth with a protective salt layer.
Dry skin・・・ Removes dead skin cells and smooths the skin, and provide deep hydration, retains moisture with a protective salt layer.
Depression・・・ Helps regulate the autonomic nervous system, activates the parasympathetic nervous system and relieves mental tension

Private bath “Ichi-no-Yu”

Private bath “Ichi-no-Yu”
The bathtub is constructed of stone and stands on a slope, providing an excellent view. It is interesting to note that the thriving trees provide just the right amount of shade.

Onsen Classification

️Hot springs are classified not only by their spring quality, but also by three additional factors: osmotic pressure, hydrogen ion concentration (pH level), and spring temperature.


Osmotic Pressure

(Hypotonic, Weakly alkaline, High temperature spring)


In hot spring classification, “osmotic pressure” refers to comparing the concentration of dissolved components in the spring water (mainly salts) with that of human body fluids (such as blood and intracellular fluid). Based on this comparison, springs are categorized as hypotonic, isotonic, or hypertonic. The difference in concentration serves as an indicator of how easily water moves between the hot spring water and body fluids.


Total Dissolved Substances


1,180 mg/kg

Classified as a Hypotonic spring


Hypotonic
(Less than 8,000 mg/kg)

Because its osmotic pressure is lower than that of human body fluids (isotonic), water is more easily absorbed into the body, which can cause the skin to soften and wrinkle more readily. However, it is less likely to cause bath fatigue (“yu-atari”) and is considered gentle on the body. Most hot springs in Japan are classified as hypotonic.

等張性 (8,000 mg/kg以上10,000 mg/kg未満)

Isotonic
(8,000 mg/kg or more to less than 10,000 mg/kg)

It has the same osmotic pressure as human body fluids. This is equivalent to a saline solution made by dissolving 8.8 g of salt in 1 liter of water. Because its concentration is close to that of body fluids, there is minimal movement of water and minerals due to osmotic pressure, making it the least stimulating and placing the least burden on the body.

高張性 (10,000 mg/kg以上)

Hypertonic
(10,000 mg/kg or more)

Water is more likely to be drawn out of the body, while hot spring minerals are more readily absorbed, allowing for stronger therapeutic effects. However, it can also cause “yu-atari” (bath fatigue) more easily and may be more physically demanding. It is generally considered a “strong” or highly concentrated hot spring.


Hydrogen Ion Concentration

(Hypotonic, Neutral, High temperature spring)


In the hot spring analysis report, the section titled “Examination and test results at gushing location” includes the listed pH value. Chemically, a pH of 7.0 is considered neutral; values below this are acidic, and values above it are alkaline. According to the “Guidelines for the Mineral Spring Analysis Methods”, the chemical nature of a mineral spring is classified based on its pH value at the time of emergence, as shown in the table below.


pH 6.4

Classified as Neutral

Hydrogen Ion Concentration

Spring Temperature


(Hypotonic, Neutral, High temperature spring)


60.5

Classified as High temperature spring

Spring temperature

Under the “Hot Springs Act”, water that contains one or more designated substances at or above the legally specified levels and has a source temperature of 25°C or higher is classified as a “hot spring”. If the temperature is below 25°C, it is labeled a “cold mineral spring”. Furthermore, as noted above, hot springs are classified by source temperature as high-temperature spring, hot spring, or low-temperature spring.


Private bath “Go-no-Yu”

Private bath “Go-no-Yu”
The private baths are full of the atmosphere of the outdoors. Although not as large as the standing baths, small groups can enjoy a relaxing soak in the baths. Of course, the source of the water is free-flowing.

Facility Data

Founded in 1955 (Showa 30)
Check in 3:00 PM
Check out 10:00 AM
Location Hot spring town
Rooms Total 14 rooms
(11 Japanese-style rooms, 2 Japanese-Western rooms, 1 Western-style room)
Capacity 50 people
Parking 20 car
Facilities Banquet hall, Shop
Internet Wi-Fi access in all areas
Barrier-free Not supported
Bidet toilet Equipped

Keywords for this inn

100% pure natural hot spring water
Variety of private baths for a relaxing onsen-hopping experience within the facility
Conveniently located on the main street of Kurokawa’s hot spring town
Reasonably priced accommodations for a comfortable and casual stay
Premium-quality meats and refined cuisine, also popular among female guests

Hot Spring (Onsen) Report

Kurokawa Onsen in Kumamoto Prefecture is now playing a textbook role for all hot spring areas in Japan. Although it is a small hot spring resort located in the mountains, the individuality of each hot spring area is not compromised, and yet the overall impression of the hot spring area is one of uniformity. As a finishing touch, Kurokawa Onsen sold “Onsen hopping pass” that allowed visitors to bathe in three baths for the purchase of one bill, and led visitors to tour the entire hot spring area while wearing yukata,... Read more →

Transportation Access

By bus ○From Fukuoka: Express buses are available via Hakata Station, Tenjin Station, and Fukuoka Airport (Nishitetsu Express Bus)
○From Kumamoto: Highway buses available via Kumamoto Station, Aso Kumamoto Airport, and Aso Station (Trans Kyushu Bus)
※For Trans Kyushu Bus, there are two types of buses: one includes sightseeing in Aso and the other does not. Also available from Beppu area.
※Sanko Bus is also available from Kumamoto area.
Nishitetsu Express Buses are available for Hita Station (many services, transfer at Hita Station) and for Tsuetate Onsen (few services).
Shuttle bus None
By car Exit at the Hita Interchange or Yufuin Interchange on the Oita Expressway
or at the Kumamoto Interchange on the Kyushu Expressway.
Address Kumamoto, Kyushu/Kurokawa Onsen/FUMOTO RYOKAN
Kawabata-dori, Kurokawa Onsen, Minami-Oguni machi, Aso-gun, Kumamoto Prefecture, 869-2402, JAPAN TEL:+81-(0)967-44-0918

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