Yusai no Yado Bokai Honkan

Analysis Verified
悠彩の宿 望海 本館
The Seaside Spring of Silky Skin

This private source gushes in the Kitahama district, part of Japan's premier onsen resort, Beppu, overlooking the bay. Located in an area that has long flourished as an entertainment district, this spring has soothed countless travelers. Combining the qualities of a bicarbonate and a chloride spring, its waters gently exfoliate the skin while a veil of salt locks in moisture. After bathing, you can enjoy a unique texture that is both silky and deeply hydrated. It is a renowned spring perfect for releasing mind and body while feeling the Beppu sea breeze.

AI Generated
This source matches 2 spring types· Tap to switch
SPRING TYPE
Bicarbonate Spring
aka "美人の湯"

Sodium bicarbonate cleanses the skin of old keratin and excess sebum, leaving skin soft and smooth. Expect beautiful skin after bathing.

See features & indications
Bathing indications
Cuts and grazesPeripheral circulatory failurePoor circulationXeroderma
Drinking indications
Gastroduodenal ulcersReflux esophagitisImpaired glucose tolerance (diabetes)Hyperuricemia (gout)

※ Only at facilities permitted to serve drinking water. 200–500 mL/day recommended.

Definition :Primary anion: bicarbonate ion.
Source: 環境省「あんしん・あんぜんな温泉利用のいろは」(監修:日本温泉気候物理医学会)Read full article
PH VALUE
8.3
Mildly Alkaline
Acidic ← 07 Neutral14 → Alkaline
Upper bound of mildly alkaline (pH 8.5). Notable soap-like cleansing and keratin-softening effects. Known as a "beauty spring".
TEMPERATURE
56.3
Very Hot Spring
Very hot. Cannot be bathed in without significant dilution.
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
234 mg/kg

A natural moisturizer also used in skincare lotions. Forms a thin veil on the skin to reduce moisture loss after bathing.

Bicarbonate ionSee detail
442 mg/kg

Softens dead skin cells for a silky bathing feel.

Metaboric acidSee detail
7.1 mg/kg

A trace component with gentle antibacterial and anti-inflammatory action.

Sodium ionSee detail
273 mg/kg

Gentle warming effect that helps you stay warm after bathing.

Carbonate ionSee detail
18.0 mg/kg

Slightly alkaline, softening dead skin cells.

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
HeatedNo
DilutedYes
RecycledNo
FilteredNo
DisinfectedNo
AdditivesNo
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
殆ど無臭
Taste
殆ど無味
EFFECTS
Spring-specific indications (bathing)
Cuts and grazesPeripheral circulatory failurePoor circulationXerodermaDepression
General indications (bathing)
High blood pressure (mild)Rheumatoid arthritisAutonomic instabilityInsomniaChronic pain or stiffness in muscles and jointsMuscle stiffness due to motor paralysisGastrointestinal dysfunction
Contraindications
Acute illness (especially with fever)Active tuberculosisMalignant tumorsSevere heart diseaseRespiratory failureRenal failureBleeding disordersSevere anemiaAny actively progressing illnessPregnancy (especially early and late stages)
BATHING TIPS
AI Generated

With a gentle pH of 8.3, this weakly alkaline water is kind to the skin, but avoid prolonged soaking. Start with a 5-10 minute dip to acclimate your body, taking breaks between soaks. The chloride components create a warming veil on the skin; for lasting effect, lightly pat dry after bathing without rinsing off.

EFFECT STORY
AI Generated

Rich in bicarbonate ions (442 mg/kg), this spring offers a cleansing effect that emulsifies and washes away old skin cells, making it ideal for achieving silky skin. Additionally, chloride ions form a thin veil on the skin, providing restorative warmth that prevents post-bath chills. With 234 mg/kg of metasilicic acid to help maintain skin moisture, it's also recommended for balneotherapy during dry seasons.

CAUTIONS
AI Generated

Indications and contraindications are listed on a separate sheet. Generally, individuals with active tuberculosis, malignant tumors, severe heart disease, or those in early or late pregnancy should avoid bathing. If you have health concerns, please consult a doctor beforehand.

※ See the analysis data below for detailed contraindications

ANALYSIS DATAView all analysis fields ▼

Source Info

Source name
Yusai no Yado Bokai Honkan
Spring type
Sodium Bicarbonate and Chloride Hot Spring
Old spring type name
含食塩-重曹泉
Source temperature
56.3℃
pH
8.3
Flow type
動力揚湯
Osmotic pressure
低張性

Analysis Document

Analysis date
2025-01-15
Analyst organization
公益社団法人大分県薬剤師会
Registration No.
大分県第3号

Cations

Lithium ion Li⁺
0.60 mg/kg
Sodium ion Na⁺
273 mg/kg
Potassium ion K⁺
42.1 mg/kg
Ammonium ion NH₄⁺
0.30 mg/kg
Magnesium ion Mg²⁺
1.8 mg/kg
Calcium ion Ca²⁺
8.7 mg/kg
Lead ion Pb²⁺
0.01 mg/kg
Copper ion Cu²⁺
0.05 mg/kg
Cadmium ion Cd²⁺
0.00 mg/kg
Total cations
0.33 mg/kg

Anions

Fluoride ion F⁻
0.20 mg/kg
Chloride ion Cl⁻
144 mg/kg
Sulfate ion SO₄²⁻
88.5 mg/kg
Bicarbonate ion HCO₃⁻
442 mg/kg
Carbonate ion CO₃²⁻
18.0 mg/kg
Bromide ion Br⁻
0.40 mg/kg
Hydrogen phosphate HPO₄²⁻
0.50 mg/kg
Total anions
0.69 mg/kg

Undissociated Components

Sulfuric acid H₂SO₄
0.00 mg/kg
Phosphoric acid H₃PO₄
0.00 mg/kg
Arsenious acid HAsO₂
0.40 mg/kg
Metasilicic acid H₂SiO₃
234 mg/kg
Metaboric acid HBO₂
7.1 mg/kg
Total undissociated
0.24 mg/kg

Dissolved Gas

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

Trace Components

Radon Rn
0 Bq/kg

Totals

Total dissolved substances
1.3 mg/kg
Component total
1.3 mg/kg
Evaporation residue
0.95 mg/kg

Usage

Heating
No
Dilution
Yes
Recycle / Filter
No
Additives
No
Disinfection
No

Indications & Contraindications

Bathing indications
Cuts and grazes, Peripheral circulatory failure, Poor circulation, Xeroderma, Depression
General indications
High blood pressure (mild), Rheumatoid arthritis, Autonomic instability, Insomnia, Chronic pain or stiffness in muscles and joints, Muscle stiffness due to motor paralysis, Gastrointestinal dysfunction
Contraindications
Acute illness (especially with fever), Active tuberculosis, Malignant tumors, Severe heart disease, Respiratory failure, Renal failure, Bleeding disorders, Severe anemia, Any actively progressing illness, Pregnancy (especially early and late stages)

Drinking

Drinkability
Not drinkable
FACILITY INFO
Official site
Tattoo
Confirming
Room with private open-air bath
Available
About tattoos and onsen
Travelers with tattoos can still bathe comfortably in a private bath (Kashikiri) or a room with a private open-air bath.
Hours
Weekdays: 11:0015:00
Weekends & holidays: 11:0015:00
Closed days: Irregular holidays
Transit
15-min walk or 3-min taxi from JR Beppu Station (JR Beppu Eki). 15-min drive from Beppu IC (Beppu IC). 40-min drive from Oita Airport (Oita Kuko).
Parking
Free parking available (40 spaces).
Day use fee
¥500Available only to dining guests. Elementary school students to 5 years old: 250 yen.
Facilities
Public BathOpen-Air BathSaunaCold BathShopVending MachinesCoin LaundryCafe
Languages supported
EN
This information may change without notice. Please contact the facility directly for accurate details.
Last updated: 6/10/2026
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
Stay at this hotel
PR

Yuusainoyado Boukai

From¥6,600/ person / night (tax incl.)
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Approx. lowest rate (varies by date & guests)

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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