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[Feature] Day-trip Hot Springs at Zao Onsen! Sunoko-no-Yu Kawaraya


Zao Onsen, which is one of the oldest hot springs in Japan, is said to have been discovered in 110 AD.

As you can see from the legend of this opening, Zao Onsen is a natural hot spring.
The hot spring has 5 main sources​ that divide from there​ into 47 individual sources​ for a flow of about 5,700 liters per minute,​ or 8,700 tons a day, quite an abundant amount of hot water.

Zao Onsen is home to many accommodation facilities, but there also are five day-trip hot spring facilities and three communal baths, so even non-staying guests can easily enjoy the hot spring waters of Zao Onsen.

This time, we would like to introduce Sunoko-no-Yu Kawaraya in this fourth article part of our feature on day-trip hot springs facilities in Zao Onsen.

Kawaraya is located in a deep and inconspicuous place, but is being called an “ultimate hot spring,” which is rare in Japan, and as such has gained tremendous support from hot spring enthusiasts.

The hint are the words “sunoko (duckboard)” and “kawara” in the facility’s name.

This time, we will introduce features of hot spring baths you will definitely want to visit after this!


Kawaraya is located in the back of the road next to Takayu-dori street, next to the communal bath Kawarayu.

Kawaraya and Kawarayu — It’s a bit confusing because the names are similar to each other, but the word “Kawara” was used in the names of the two adjacent facilities in the past because this area used to be called “Kawara-machi.”

And the reason why this place was called “Kawahara Town” is because it was “Kawahara.”

The word “kawara” is also hiding the secret of Kawaraya, but I will introduce it later ♪

New and clean hall

Kawaraya was originally a historic hot spring inn called Kawaraya Ryokan.
It was renovated in 2011 and reopened as a facility mainly for day trip bathing.

Therefore, the hall is still new and kept very clean.

Shoe shelf


Front desk


When you go up to the hall, there is a ticket vending machine on the front desk, so please buy a ticket here and give it to the staff.

[Bath fee] Adult: 500 yen (tax included)
Child: 300 yen (tax included)
Book of tickets: 5,000 yen (tax included)
         * 12 tickets included
[Bath time] 10:00~18:00 (for the time being)

Hair dryer rental


By the way, there is a hair dryer for rent on the front stand here.

There is no hair dryer installed in the dressing room, and there is no outlet for the hair dryer, so if you need it, ask here.​ After bathing​ you can rent it and hang it on the washbasin next to the lobby.

Some people may find it a little inconvenient, but the reason there are no outlets in the dressing room or the wash basin near it is to prevent corrosion of the electrical wiring as much as possible.

Zao Onsen is a strongly acidic hot spring that contains hydrogen sulfide.
Due to its power, electrical appliances can get inoperative in less than a few years, and iron products can quickly rust.

The same is true for electrical wiring, etc., especially near the bathtub, the outlets do not last long, and in some cases it may even lead to electric leakage.

As I will introduce later, the source of Kawaraya is just over the bath rooms, so this dryer rental system is set like this for safety reasons.



The lobby is very clean and spacious.



The restroom is right next to the front desk.

There is a washbasin (pictured below) where you can use a hair dryer, and the restroom is in the back.


Now, beyond the curtain...


By the way, you will see this noren curtain on your right end once you enter.

Passing through this curtain, there are several steps, and beyond that there is a unisex wash basin and a dressing room.




Dressing room (men's bath)


Dressing room (women's bath)


Shower room separated by a door

The shower room is at the back of the indoor bath.

Since it is separated by a door, there is no need to worry about soap, shower hot water or shampoo entering the bath tubs.

Men's bath


Women's bath


There are two wash spots with shower for men’s and women’s areas.

Rinse-in shampoo and body soap are also provided, but it seems that many regulars bring their own bathing set.

A hot spring that fans love and never stop coming too

Here is the long-awaited introduction of a unique hot spring in Japan!

Men's bath


Women's bath


Both the building and the bathtub are made of wood and have a calm appearance.
The bathtub itself is small and can only fit 4 to 5 people.

However, please take a closer look at the area around the bathtub.
Did you notice that you can’t find the spout from which the water comes?

The surface of the water does not seem to be moving, but if you look closely, you can see that the hot water is constantly overflowing from the bathtub.

So where does the hot water come from?
The answer is the reason why this Kawaraya is said to be rare in Japan.

The secret of Sunoko-no-Yu

By the way, the official name of this facility is “Sunoko-no-Yu Kawaraya.”

Please see the bottom of the bathtub.
You can see that it is like a duckboard.


The bath of Kawaraya is actually located just above the spring source itself, which is rare in Japan.
A duckboard is laid on the bottom of the bathtub, and the hot spring water is springing up directly between the slats.

The spring water of Zao Onsen is said to be particularly effective against skin diseases, and many visitors have visited its many hot springs facilities for a long time.
However, not limited to Zao Onsen, water from hot springs start to oxidize from the moment it comes into contact with the air, diminishing its effects over time.

However, you can enjoy the fresh hot spring water not exposed at all to air at Kawaraya, as it comes naturally from the ground and springs at your feet.


Do you see that there is a hole at the bottom of the bathtub, behind the duckboard gap?

Hot water is coming out of this hole.

In this area, which was once called “Kawara Town,” hot water from the source was flowing as a river. You can still see its remnants near the back of the communal bath Kawara-yu.

Kawaraya and Kawarayu do not pull the hot spring waters into the bathtubs like ordinary hot springs, but instead placed their bathtubs with drainboards on the spots the water is springing up from. It is a hot spring on the river.
* By the way, Kawarayu and Kawarayu are built similarly but the style of their bathtubs, and their sides, are slightly different. Kawaraya has a slatted shape, but only at the feet (and the boundary between men and women), it spouts only from the feet, while Kawarayu has a grid pattern on all sides, and at the feet, the structure is such that hot water comes in not only from the bottom but also from the sides.

After taking a bath, relax in a private tatami room

By the way, after soaking in a fresh hot spring, you will want to relax in a tatami room.

Kawaraya has two rooms to rest, Chigusa and Suitsuki, so I would like to introduce them as well.


The two rooms are no different in size and amenities.







There is a table and two chairs at the back of the room.


When you open the shoji screen, bright light comes in.

It’s great to be able to relax while looking at the garden in the tatami room after taking a bath.


The room is equipped with a TV, a safe, a heater and even a washbasin.

[Usage fee] 2 hours: 2,000 yen (tax included)
   * Extension fee is 800 yen per hour

Light meals in the lobby ◎


Light meals and drinks are also provided, so you can relax here after taking a bath.

Light meal


* Please check directly as meals may not be served on some days.



Yamagata souvenirs


They also have souvenirs using Yamagata’s special products.

For those who want to experience clear hot spring water


Many people may think of muddy hot water when asked about Zao Onsen’s hot water.

The hot water that springs from the source is​ colorless and transparent. When the transparent hot water comes into contact with the air, it oxidizes and becomes white.

Please check it when you go to the hot springs of Zao Onsen next time.
The hot water after people entered is cloudy due to the mixture of air, but you can see that the hot water at the sprue and the hot water in the bathtub before people enter are clear.

At Zao Onsen, there are many facilities that are devised to provide visitors with as fresh hot water as possible, but this Kawaraya hot water is rare because you can enjoy the quality of the hot spring before it comes into contact with the air.

Message from the staff


“It’s a rare bath in Zao Onsen, so I definitely want to recommend it to people.”


Saito Chiharu, the daughter of the representative.

Why don’t you go to Kawaraya to enjoy this precious hot spring?

Onsen information

Facility name Sunoko-no-Yu Kawaraya
Source name Kawaraya Gensen
Water qualities Acid / sulfur-containing-aluminum-sulfate / chloride
Source temperature 51.1 ℃
Bath temperature 43.0 ℃
Added water Since the source temperature is high, tap water (well water) is added to control the temperature.
Heating No additional heating is applied to the source water
Overflow & filtration The hot spring water is flowing freely directly from the source
Additives h salts or disinfectants are used
Other It is a source that spouts from under the bathtub

Detailed information

Sunoko-no-Yu Kawaraya

Sunoko-no-Yu Kawaraya

43 Zao Onsen Kawara, Yamagata City, Yamagata Prefecture


Detailed information

[Summary] Zao Onsen! All eight day trip bathing facilities

[Summary] Zao Onsen! All eight day trip bathing facilities

Introduction of Shinzaemon-no-Yu, Center Plaza Yu-Yu, Kawaraya, Genshichi Roten-no-Yu, Zao’s Large open air bath and public bathing facilities!
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