Kaikiso

Analysis Verified
海喜荘
Taisho Roman's Silky Spring

The Kaikiso source is the private spring of Kappo Ryokan Kaikiso, an inn established in 1922. It has been carefully preserved on the tranquil coast of the Kunisaki Peninsula. Rich in metasilicic acid, this spring is known for promoting skin metabolism and is often called a "skin-beautifying spring." The soft, clear water gently envelops both body and mind, perfect for those seeking a peaceful bathing experience in a historic setting.

AI Generated
PH VALUE
7.5
Neutral
Acidic ← 07 Neutral14 → Alkaline
Upper bound of neutral (pH 7.5). Approaching mildly alkaline, the boundary where skin starts to feel smooth.
TEMPERATURE
18.5
Cold Mineral Spring
Too cold to bathe directly; requires heating.
KEY MINERALS

The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).

Metasilicic acidSee detail
53.4 mg/kg

A natural moisturizer that leaves a hydrated feel on the skin.

Bicarbonate ionSee detail
175 mg/kg

Softens dead skin cells for a silky bathing feel.

Magnesium ionSee detail
10.2 mg/kg

Transdermal absorption gently supports skin hydration and muscle relaxation.

Fluoride ionSee detail
0.2 mg/kg

A trace antibacterial component that keeps skin clean.

Calcium ionSee detail
35.9 mg/kg

Gentle astringent action that conditions the skin.

CHARACTER · COMPOSITION PROFILE
1234StimulationBactericidalSkin BeautyHeat RetentionRelaxation

Scores are calculated from mineral analysis data based on the Mineral Spring Analysis Guidelines (Ministry of Environment, Japan). They are unrelated to facility atmosphere or service quality.

USAGE
Usage status is unknownInformation from facility postings or official sites has not been confirmed. Please check with staff on site.
Note

The temperature, pH and component values shown here are based on the hot spring analysis (source). Actual values in the bath may differ depending on heating, dilution, recycling and filtration. Please check current usage status at the facility.

SENSORY TEST
Color
無色澄明
Smell
無臭
Taste
無味
EFFECTS
Spring-specific indications (bathing)
Chronic pain or stiffness in muscles and jointsMuscle stiffness due to motor paralysisPoor circulationPeripheral circulatory failureGastrointestinal dysfunctionHigh blood pressure (mild)Impaired glucose tolerance (diabetes)Mild hypercholesterolemiaMild asthma or emphysemaHemorrhoid painAutonomic instabilityStress-related symptoms (insomniadepressionetc.)ConvalescenceFatigue recoveryHealth promotion
Contraindications
Active stages of illness (especially with fever)Active tuberculosisAdvanced malignant tumors or severe anemia causing significant physical weaknessSevere heart or lung disease causing shortness of breath with light activitySevere kidney disease with swellingGastrointestinal bleedingVisible bleedingAcute exacerbation of chronic illness
BATHING TIPS
AI Generated

As this is an 18.5°C cold spring, it is heated for bathing. The water is soft and rich in metasilicic acid, making it gentle on the skin. A long, slow soak is recommended to promote deep relaxation. Moisturizing after your bath will help maintain the skin's silky feeling.

EFFECT STORY
AI Generated

With a weakly alkaline pH of 7.6 and 53.4 mg/kg of metasilicic acid, this spring meets the official onsen criteria. This component, a natural moisturizing agent, may support skin metabolism, leading to a silky skin texture. Its gentle quality is perfect for deep relaxation and relieving daily fatigue. As a form of balneotherapy, it can help restore balance to mind and body.

CAUTIONS
AI Generated

There are no specific contraindications, but as a general precaution, avoid bathing when unwell or after consuming alcohol. The water is drinkable, but excessive consumption should be avoided.

※ See the analysis data below for detailed contraindications

ANALYSIS DATAView all analysis fields ▼

Source Info

Source name
Kaikiso
Spring type
Hot Spring
Old spring type name
弱アルカリ性低張性冷鉱泉
Source temperature
18.5℃
pH
7.5
Flow type
動力揚湯
Osmotic pressure
低張性

Analysis Document

Analysis date
2020-06-24
Analyst organization
公益社団法人大分県薬剤師会
Registration No.
大分県第3号

Cations

Sodium ion Na⁺
35.0 mg/kg
Potassium ion K⁺
5.2 mg/kg
Magnesium ion Mg²⁺
10.2 mg/kg
Calcium ion Ca²⁺
35.9 mg/kg
Lead ion Pb²⁺
0.00 mg/kg
Strontium ion Sr²⁺
0.30 mg/kg
Copper ion Cu²⁺
0.00 mg/kg
Cadmium ion Cd²⁺
0.00 mg/kg
Total cations
0.09 mg/kg

Anions

Fluoride ion F⁻
0.20 mg/kg
Chloride ion Cl⁻
24.6 mg/kg
Sulfate ion SO₄²⁻
24.1 mg/kg
Bicarbonate ion HCO₃⁻
175 mg/kg
Bromide ion Br⁻
0.10 mg/kg
Nitrate ion NO₃⁻
9.9 mg/kg
Hydrogen phosphate HPO₄²⁻
0.50 mg/kg
Total anions
0.23 mg/kg

Undissociated Components

Sulfuric acid H₂SO₄
0.00 mg/kg
Phosphoric acid H₃PO₄
0.00 mg/kg
Arsenious acid HAsO₂
0.00 mg/kg
Metasilicic acid H₂SiO₃
53.4 mg/kg
Metaboric acid HBO₂
0.20 mg/kg
Total undissociated
0.05 mg/kg

Dissolved Gas

Free carbon dioxide CO₂
9.2 mg/kg
Free hydrogen sulfide H₂S
0.00 mg/kg
Total dissolved gas
0.01 mg/kg

Trace Components

Radon Rn
0

Totals

Total dissolved substances
0.38 mg/kg
Component total
0.38 mg/kg
Evaporation residue
0.28 mg/kg

Usage

Usage status
Unknown

Indications & Contraindications

Bathing indications
Chronic pain or stiffness in muscles and joints, Muscle stiffness due to motor paralysis, Poor circulation, Peripheral circulatory failure, Gastrointestinal dysfunction, High blood pressure (mild), Impaired glucose tolerance (diabetes), Mild hypercholesterolemia, Mild asthma or emphysema, Hemorrhoid pain, Autonomic instability, Stress-related symptoms (insomnia, depression, etc.), Convalescence, Fatigue recovery, Health promotion
Contraindications
Active stages of illness (especially with fever), Active tuberculosis, Advanced malignant tumors or severe anemia causing significant physical weakness, Severe heart or lung disease causing shortness of breath with light activity, Severe kidney disease with swelling, Gastrointestinal bleeding, Visible bleeding, Acute exacerbation of chronic illness

Drinking

Drinkability
Not drinkable
Drinking notes
Drinking is not permitted by the public health center.
FACILITY INFO
Official site
Tattoo
Confirming
About tattoos and onsen
Hours
Check-in 4:00 PM, Check-out 10:00 AM
Closed days: Open daily
Transit
From JR Kitsuki Station (JR杵築駅): 30 min by taxi, 1 hr by bus (Kunisaki (国東) final stop). From Oita Airport (大分空港): 12 min by taxi, 20 min by bus (Yokomachi (横町) bus stop at entrance).
Parking
Available, 10 spaces, Free
Facilities
Free Wi-FiTea LoungeBanquet HallVending MachinesPC availableMassage ServicePublic BathFree EV Charging
This information may change without notice. Please contact the facility directly for accurate details.
Last updated: 6/7/2026
How Long to Stay (Toji)
Start with 2 nights / 3 days

Japan’s Ministry of the Environment notes that even a short stay refreshes you. For a full therapeutic cure, around 2–3 weeks is the guideline.

More on toji length
The descriptions, catch phrases, and translations on this page are generated by AI (Claude). pH, temperature, and component values are OCR-extracted from the official analysis report. Learn more