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Asaya Hotel

鬼怒川温泉 あさやきぬがわおんせん あさや

Lodging
Kanto·Tochigi

Day Use

No

Bathing & Water

Natural onsen water

Uses natural hot spring water

Outdoor BathYes

Open-air outdoor bath

Indoor BathYes

Enclosed indoor bathing area

SaunaYes

Dry heat sauna room

Capabilities

Private BathYes

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

Four themed private tubs (granite, rock, hinoki, red granite), reservation-based, 50 min / 4,000 yen; water is recirculated (循環式).

Room OnsenYes

Private onsen bath in guest rooms, for overnight guests only

Mixed BathingNo

Shared bathing area for all genders

Policies & Services

TattooWith Conditions

Allows entry with visible tattoos

Tattoos are not allowed in the large communal baths (a private bath or in-room bath may be used instead); a small one-point tattoo is allowed in the large bath if fully covered with a cover seal (sold at the hotel gift shop).

KidsWith Conditions

Welcomes children and families

Children up to age 6 may enter the opposite-gender bath with a parent; from age 7, mixed-gender bathing is prohibited by Tochigi prefectural ordinance.

DiningYes

Restaurant or dining open to visitors (not just hotel meal plans)

WashingYes

Shower, wash stations, soap and shampoo provided

ParkingYes

On-site or nearby parking available

Water treatment

Not disclosed
from Article 18 disclosure
  • Added water
    Not disclosed
  • Reheated
    Yes
  • Recirculated
    Not disclosed
  • Disinfected
    Yes
    塩素系薬剤
  • Bath additives
    No

あさや源泉(子宝の湯)

Asaya Spring (Kodakara-no-yu)

Operated by · 株式会社あさやホテル

Simple
Color
colorless and transparent
Taste
tasteless
Odor
odorless

Sodium Sulfate-Chloride spring

pH 8.8AlkalineTop-decile alkaline
Composition fingerprint0.3 g/kg dissolved · Hypotonic
Na⁺88
SO₄²⁻39
Cl⁻37
CationsAnions
Sodium Na⁺
salt's cation — pairs with chloride to make the water salty.
Sulfate SO₄²⁻
"gypsum / Glauber's salt" — vessels and wound healing.
Known good for
  • Smooth skindry, rough skin
  • Recoveryfatigue, stress

Asaya's "Kodakara-no-yu" wellhead is a simple alkaline thermal spring (hypotonic, alkaline, normal-temperature class). Both the on-site pH 8.8 and the laboratory pH 8.77 sit well into alkaline territory, giving the characteristic slippery, skin-smoothing feel of Japan's "beauty-water" family. The water is lightly mineralized — 0.304 g/kg dissolved solids and 0.311 g/kg evaporation residue — which keeps the bath gentle, with little of the assertive mineral edge of stronger chemistries. Colorless, tasteless, and odorless at the spout, it presents as a soft, unobtrusive single-thermal source whose appeal lies in the alkaline silk-water feel rather than in pronounced ions or aroma.

Sampled at wellhead·Analyzed Jul 8, 2022·一般社団法人 栃木県薬剤師会·Cert no. 第14感第1号

Explore the water

Views

Mountains
City

Highlights

Ganbanyoku
Boat Bath

About

Asaya is a large hotel-style ryokan split across two wings, Shuhoukan and Hachibankan, with 192 rooms, every one plumbed with the hotel's own onsen water and some opening onto their own kakenagashi view bath or an attached outdoor tub. The showpiece is the rooftop sky garden bath at the top of Shuhoukan, the highest bath in Kinugawa Onsen, laid out as several small tubs, among them a standing bath honoring a dragon guardian of a nearby gorge and a boat-shaped tub, funayu (舟湯), modeled on the boats used for the river's line-boat rides. Each wing also has its own large indoor bath with a loyly steam sauna and a nano-mist sauna, plus four small reservable private baths in granite, rock, hinoki and red granite tubs, themed around a lucky mallet said to grant wishes. The water is an alkaline hot spring from Asaya's own source, drawn from a stretch of the Kinugawa valley long said locally to be good for healing burns and cuts. Inside, the hotel opens into a tall atrium of chandeliers and glass elevators with a pipe organ playing in the lobby, more grand hotel than quiet mountain inn.

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GreyChertZ

1 year ago

Well, looks like I've finally grown enough to write a review. Huge Hotel Asaya, with an "American-style system" where everything is available inside the hotel but for a fee. There are rooms with their own rotenburo. 3 different onsen areas — on the roof, on the 1st floor of one building, and on B1 of another building. Let me start with what I didn't like. On the roof (13th floor) it's beautiful of course, but the water... it really smells like chlorine. For me it was literally unbearable. Everything costs extra, even playing pool. I don't like that. Something unusual for me — this is a really family-friendly onsen. The baths have accessories for kids: seats, little boats, that sort of thing. The onsens on the lower floors are better. No smell, there's a rotenburo with a small window. I liked that each onsen area has a common room where you can hang out before heading back to your room. The water is clear but has an effect on the skin — oily. For families this is definitely a top choice. But as a seasoned onsen veteran, it's just meh. Nice views though.

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Last updated July 19, 2026