Public Bath No.5 Matsu-no-yu

Day Use

Yes

06:00–22:00

with a key when staying at the ryokan

¥0

if you have a key when staying at the ryokan

Bathing & Water

Natural onsen water

Uses natural hot spring water

Outdoor BathNo

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

SaunaNo

Dry heat sauna room

Cold BathNo

Cold water plunge bath, typically used after sauna

Capabilities

Private BathNo

Private bath available for day-use visitors or hotel guests to reserve

Room OnsenNo

Private onsen bath in guest rooms, for overnight guests only

Mixed BathingNo

Shared bathing area for all genders

Policies & Services

WashingNo

Shower, wash stations, soap and shampoo provided

横湯第一ボーリング、横湯第二ボーリング、熱の湯の混合泉

Yokoyu No.1 Boring, Yokoyu No.2 Boring & Netsu-no-yu Blend

Mixed source

塩

Chloride

+ Sulfate

Color: colorless and clear
Taste: slightly salty with a faint sulfur note
Odor: not recorded

Sodium-Calcium Chloride-Sulfate spring

pH 8.0Weakly alkalineHot source · 87°C

Composition fingerprint1.6 g/kg dissolved · Hypotonic

Na⁺69

Ca²⁺26

Cl⁻60

SO₄²⁻36

◀ CationsAnions ▶

Sodium Na⁺: salt's cation — pairs with chloride to make the water salty.
Chloride Cl⁻: table-salt anion — coats the skin and holds heat in.

Known good for

Warmingcold sensitivity
Circulationtired legs
Aches & jointsstiff shoulders

A sodium-calcium chloride-sulfate spring, weakly alkaline and soft on the skin. The wellhead runs at 86.5 °C, putting it among Japan's hottest natural sources (cooled before bathing). The water is almost colorless and clear, slightly salty with a faint sulfur note, and moderately mineralized at 1,611 mg/kg of dissolved solids for noticeable body.

Sampled at bath inlet·Analyzed May 26, 2016·一般社団法人上田薬剤師会検査センター·Cert no. 中28-2(No.427)

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