One of the largest spa complexes of the Kanto Region, SPADIUM JAPON
Discover all the “Nagoya-style” Appeal at SPADIUM JAPON!
The Crystal-Clear Musashino Hot Spring Bathwater
5 Bedrock Baths: Beauty from the Inside Out

Japan is dotted with huge spa complexes called “super sentos”, with many located in Tokyo. In March 2019, another massive bathing complex opened in suburban Tokyo, in Higashikurume City, offering reasonable prices and an array of fun experiences that were missing from Tokyo’s earlier facilities. The new venue called SPADIUM JAPON is the talk of the town as it draws many visitors everyday, including students, families, couples, and lone bathers.
What makes SPADIUM JAPON so appealing? We have visited this “super sento” to find out more about its concept, as well as its most important features - the baths and bedrock baths. Join us as we find out how this venue captivates its visitors!

One of the largest spa complexes of the Kanto Region, SPADIUM JAPON

Various super sentos (spa complexes) operate across Japan. A “super sento” refers to any non-accommodation bathing facility larger than a regular public bath. New super sentos are increasingly offering more than just large bath rooms, adding services such as food courts, and relaxation rooms, that let visitors stay longer and relax to their heart's content. 
In Tokyo’s 23 wards alone, there are more than 100 super sento complexes. 

Hot spring image

Super sento bathing sites are scattered across Japan

SPADIUM JAPON, which opened in March 2019, is drawing attention as an innovative super sento. Although it is located outside Tokyo’s central 23 wards in Higashikurume City, SPADIUM JAPON is within easy reach from central Tokyo with a roughly 20-minute rapid ride from Ikebukuro Station. It celebrated its first anniversary as of March 2020, and is now widely recognized as “supa-japo”.


SPADIUM JAPON exterior. Beautifully lit up at night. (Photo Courtesy: SPADIUM JAPON)

The huge dome-shaped SPADIUM JAPON stands on a massive plot of land where a housing complex once stood. The nearest bus stop “Higashikurume Danchi (housing block)” serves as a reminder of the land’s past. 

About 10 years from now, the housing block was filled with residents and a shopping street stood nearby. However, as the passage of time brought a decrease in population, the neighborhood gradually lost its vitality. The city drew up a plan to redevelop the neighborhood to save it from decline. It had already been confirmed that a natural hot spring was flowing underground, so the city decided to build a bathing facility. After years of trial and error, SPADIUM JAPON finally opened in 2019.

Discover all the “Nagoya-style” Appeal at Spadium Japon!

Before we explore the appeal of SPADIUM JAPON, let us quickly look back at the history of Japan’s super sentos.
The very first super sento is open to question, but it is generally considered to be Ryusenji-no-yu which opened in 1990 in Nagoya City, Aichi Prefecture, in central Japan. This means Nagoya is the birthplace of super sento baths. A lot of attention goes into the details of Nagoya’s super sentos, and many of their common characteristics are collectively referred to as the “Nagoya-style”.  
SPADIUM JAPON is actually run by a Nagoya business, and the spa complex is awash with such Nagoya-style features. 

Super-reasonable prices 

Price is often the decisive factor when it comes to choosing a super sento. Admission to many of Tokyo’s super sentos costs nearly 3000 yen, which includes access to the bathrooms and bedrock baths. Entry to SPADIUM JAPON is reasonably priced at just 750 yen on weekdays (850 yen on Saturdays, Sundays, and public holidays), and only 1,400 yen even when combined with the bedrock bath.  


SPADIUM JAPON has drawn attention for its “overly generous prices”. (photo courtesy:SPADIUM JAPON)

The reasoning behind the affordable entry fee at SPADIUM JAPON, pricing itself under 1,500 yen, is quite simple. The Nagoya-style thinking goes: “the cost of heating a bathtub is the same regardless of how many people use it. Then, why not make it affordable for more people to come?” SPADIUM JAPON hopes for many people to come to relax, and offers exceptionally low prices rarely seen in Tokyo. 

Brightly colored in-house wear 

Clothes worn inside SPADIUM JAPON

Photogenic clothes worn inside SPADIUM JAPON.

Another Nagoya-style feature of SPADIUM JAPON is the colorful clothes worn indoors. Guests can choose from a wide selection of flower patterns reminiscent of resort wear, that are sure to boost one’s mood just by putting them on. Many young people can be spotted at SPADIUM JAPON taking photos of themselves in these photogenic clothes. Similarly, the shoe racks and lockers are also decorated with bold designs. 

Monthly events. 

The Nagoya-style concept is all about keeping up with popular trends to provide services that make customers happy. SPADIUM JAPON holds various seasonal, monthly and daily events. 
Apart from special occasions such as Christmas and Valentine’s Day, SPADIUM JAPON also runs yoga classes on the same floors as the bedrock baths, and hosts an event called “SUPER SWEET DAY” when the food court offers discounts on certain dessert sets. At SPADIUM JAPON, the staff are constantly working behind the scenes, analyzing customer feedback and other ideas to offer fun and exciting programs every day. 

A great variety of baths 

SPADIUM JAPON’s outdoor bath

The wide variety of baths. main advantage of SPADIUM JAPON (Photo credit: SPADIUM JAPON)

The largest draw of the Nagoya-style is its vast selection of baths. Being a large-scale super sento bath complex allows SPADIUM JAPON to offer a staggering variety of 15 distinct bathing experiences.. These include carbonated baths, which have now become a regular feature of Japanese public baths, silk baths, fragrant baths, and jet baths. There are also 2 types of saunas, so guests can enjoy their favorite bathing method to their heart’s delight. 

SPADIUM JAPON’s outdoor ‘tsuboyu’ baths/

The open-air baths are beautifully lit up at night(Photo courtesy:SPADIUM JAPON)

Hot spring-lovers behold! The Crystal-Clear Musashino Hot Springs

Along with SPADIUM JAPON’s huge selection of baths, the hot water filling the tubs also play an important role. Next, we will explain why the venue is even recommended for those seeking a full-fledged hot spring experience at a super sento bath house. 

Two baths made possible by Higashikurume’s location 

Natural hot spring

Outdoor bath filled with water drawn from Musashino Onsen hot spring(Photo courtesy: SPADIUM JAPON)

SPADIUM JAPON is a rare example in Tokyo of a super sento bath that draws from a natural hot spring. While one of Tokyo’s most famous hot spring areas flows with naturally black water,  Higashikurume (where SPADIUM JAPON is located) flows with transparent and colorless water of the  Musashino Onsen hot springs.
For a reasonable price of 750 yen, you get to soak in a hot spring that delivers beautiful skin. 

At first glance, the hot spring water appears to have a light texture, but it is categorized as a sodium-chloride-bicarbonate spring, which is said to make skin beautiful. It is the perfect bathwater that combines the skin-conditioning properties of a sodium spring, while naturally containing carbonic acid, a standard ingredient of skin-caring hot springs. You can experience all of this for the reasonable price of just 750 yen!

■Bathtubs filled with water drawn from one Japan’s best water sources
Tub featuring spring water from one of 100 best waters

Tub filled with spring water from one of Japan’s 100 best water sources (Photo courtesy:SPADIUM JAPON)

SPADIUM JAPON has another crucial advantage, apart from the natural water drawn from the Musashino Onsen hot spring. It uses water that is ranked among Japan’s 100 best water sources. 
Higashikurume is the only area in Tokyo with natural spring water that is included on a list of Japan’s 100 best waters of the Heisei era (1989 - 2019) SPADIUM JAPON fills its bathtubs with this clear, natural spring water. For instance, the foam bath inside the open-air bath zone is filled with spring water mixed with highly concentrated carbonic acid, which further enhances the water’s skin beautifying effects. 

Infused with High-Concentration Carbonic Acid: An Original Bathwater Blend

SPADIUM JAPON’s bathing area

Tubs filled with water from Musashino Onsen infused with highly concentrated carbonic acid (Photo Courtesy: SPADIUM JAPON)

Carbonated acid springs are a common feature of super sento baths. These baths that mix carbonic acid with hot water are known to promote blood circulation and relaxation. 

For readers unfamiliar with this topic, a carbonic acid spring is defined as having a carbonic acid concentration of 250ppm and above. The figure is 1,200ppm on average for highly concentrated carbonated springs. It goes without saying that the higher the concentration of carbonic acid, the higher its medicinal effects in the bathwater. SPADIUM JAPON’s high concentration carbonate spring baths boast an astonishing level of carbonate content of 5000ppm. This is because high concentrations of carbonic acid is further mixed with water that naturally contains carbonic acid. 

Hot water tubs to enjoy onsen bathing 

The ”piping hot water” tub is filled with water drawn from a natural hot spring (Photo courtesy: SPADIUM JAPON)

Do not underrate SPADIUM JAPON as a mere super sento bath complex. SPADIUM JAPON’s bath water is remarkable because of the water itself, and the attention given to managing the spring quality. This spot even fits the bill for those seeking an authentic hot spring experience.

5 Bedrock Baths: Beauty from the Inside Out

Another appeal of SPADIUM JAPON is its bedrock baths located on the 5th and the middle 5th floors. 


One of the bedrock baths. FOREST TERACCE.(Photo courtesy: SPADIUM JAPON)

SPADIUM JAPON has five types of bedrock baths with different temperatures, which guests can bathe in as many times as they want. On top of that, guests can also borrow an unlimited number of books from the private “IN THE FOREST LOUNGE” on the 5th floor, where more than 30,000 manga comic books and more than 120 magazines are available. Bring manga comic books and magazines into the lounge space modeled after a forest, for a relaxing time. The bedrock bath floors are the largest in the Kanto region (the area surrounding Tokyo), and one of the biggest draws of SPADIUM JAPON. 

I myself, the writer of this article, went to get a first-hand experience of the bedrock baths. If you find yourself lost in the varied facilities and spacious floors, and don’t know how to get the most out of the bedrock baths, we have you covered! Read on for tips that will help ease your worries, and guarantee a great time even if you are visiting alone. 

1. Choose manga comics to read

SPADIUM JAPON’s bedrock bath area has one entrance and exit. After passing through the entry gate, manga comics and magazines are displayed on the right side, with the private lounge to your left. As a start, choose manga comics and magazines to read while bedrock bathing. Up to 5 books are allowed to be borrowed at a time. A wide variety of manga comics are available, including those for children, youth, and older audiences.

Bedrock bathing floor

bedrock bathing area with spacious lounge. The manga comic shelves can be seen in the back. (Photo courtesy:SPADIUM JAPON)

After picking up your comic books, walk through the right hallway towards the bedrock bathing zone on the middle-5th floor. 
The special clothes you need to wear indoors will be damp with sweat after entering the bedrock baths, so if you wish to enjoy reading while resting, I recommend spending time at the lounge before heading to the bedrock bathing zone. 

2. Enjoy the 5 bedrock baths 

Bring your choice of comic books with you to the bedrock bathing zone. This area on the middle-5th floor houses 5 rooms of different temperatures and stones. 

Listed in the order of their room temperatures (the coolest room comes first), the five rooms are named ”HANG LOOSE ROOM”,”FOREST TERRACE”, ”COLORED FOREST”, “FOREST BATH” and “RED HOT ROOM”.

bedrock bath ‘HANG LOOSE ROOM’

The “HANG LOOSE ROOM” has the coolest room temperature (about 41℃)(Photo Courtesy: SPADIUM JAPON)

The room temperature inside a bedrock bath is normally set at 40℃〜60℃. Inside SPADIUM JAPON’s bedrock bathing areas, the room temperatures are variously set between the lower 40s to lower 60s. When choosing a room, it is recommendable to check the temperature and the stones embedded in the room. 


“COLD FOREST” is fitted with agate stones that are said to help reduce stress (Photo Courtesy: SPADIUM JAPON)

I first tried the “FOREST BATH”, where the temperature is set between 53℃~56℃. It is the second hottest bedrock bathroom. 
While some may recommend visiting the cooler bedrock baths first to let your body get used to the heat, I suggest starting with the warmer rooms (40℃~50℃) if you can, to better enjoy all 5 rooms. This is because your metabolism improves as the temperatures gradually get higher, which makes yourself prone to stamina loss by the time you visit the hotter rooms. 

Bedrock baths are fitted with heated rocks and stones that emit infrared rays, which are said to help relieve physical discomfort. Different types of rocks and stones are embedded in the rooms and booth floors, delivering different health benefits and effects. 
The FOREST BATH, which I tried first, featured eight medical stone slabs. This time I chose the famed “benibakuhanseki” (red barley stone), which releases infrared rays and minus ions, and is said to improve skin elasticity and increase the body’s oxygen supply. 

”FOREST BATH” features 8 medical stones

”FOREST BATH” embedded with 8 medical stones

I drank lots of water and was fully prepared. I spread a large towel on the floor and lied down on it. 
I spotted a few people using their smartphones, as cell phone use is permitted, but I would advise against using phones they will heat up. I spent a relaxing time reading the comic books that I borrowed. I lied on my stomach for the first 5 minutes, and then spent the next 5 minutes lying on my back. Both sides of the body need to be warmed to properly reap the benefits of bedrock bathing. 

I drank fluids every once in a while as I broke a sweat. Once you feel warm from within and have had enough sweating, you can leave the room when you like. 

3. Cool down in a special room to improve your blood circulation 

Cooling down after a bedrock bath is essential to maximizing the effects of bedrock bathing. 
SPADIUM JAPON’s bedrock bathing zone has a room specifically designed for this purpose called “COLD HOUSE” where the room temperature is set at 12℃. The octangular room has a huge pile of ice (that almost looks like a shaved ice dessert) placed in the center, with benches surrounding it. Surprisingly, it is designed to make snow fall from the ceiling of the COLD HOUSE at regular intervals. This is just another presentation of SPADIUM JAPON’s Nagoya-style service. 


“COLD HOUSE” simulates a snowfall. (Photo courtesy:  SPADIUM JAPON)

A full body cool down not only makes skin firmer, but also improves blood circulation. Repeat several rounds of bedrock bathing, each followed by a cool down session, to experience the full benefits of bedrock bathing. 

bedrock bath in ‘Honeycomb zone’

The “Honeycomb box” zone in the “HANG LOOSE ROOM” is popular with couples because it offers privacy. (Photo credit:SPADIUM JAPON)

Borrow more comic books or take a break in the lounge and cafe area, and enjoy bedrock bathing to your heart’s content. There is no time limit and SPADIUM JAPAN has a very generous rule of allowing guests to freely move between the floors housing the large bathrooms and bedrock baths. 
A staff worker told me that students come to study and office workers are spotted here working on weekdays. SPADIUM JAPON is indeed an amazingly comfortable space. 

Enjoy a full-on hot spring and bedrock bath experience at SPADIUM JAPON

SPADIUM JAPON in the Tokyo suburbs of Higashikurume is the kind of place that makes everybody, including students, families and lone visitors alike, forget the passing of time in a moment of relaxation. The large bathrooms and bedrock baths have been created and designed with passion and the entire bath complex itself offers an authentic hot spring experience for a reasonable price. In March 2020, SPADIUM JAPON marked its first anniversary since its opening, and a massive event was being planned at the time of this article’s writing. I hope you visit SPADIUM JAPON on this special occasion.