What do you miss the most about Japan, friends ask me when they find out I lived there for over a decade. The onsen, or hot springs, I’d always reply without hesitation, truly one of the most unique, enjoyable features of what can be a pretty stressed-out society. There’s something magical about the healing, steamy water that lifts the soul.

So in July during a brief family visit to Tokyo, I made a beeline for the Takaragawa Onsen in Gunma Prefecture—a group of four large outdoor spas roughly an hour and a half from the capital by bullet train.

Cleanser: (left) A view of Takaragawa Onsen. Courtesy Takaragawa Onsen; and autumn is a good time to visit the spas as the foliage turns orange at this time. Nobiinue/Wikimedia

Takaragawa is famous for its spectacular open-air pools beside a fast-running river deep in a stretch of scenic mountains, a truly breath-taking experience for bathers. It’s also one of the few places left in Japan that still offers konyoku, or co-ed baths, as the country embraces modernity— and Western ideas of modesty.

The beautiful spas are for the exclusive use of guests staying at the attached Japanese ryokan (traditional inn) hotel. But between 9am and 5pm, they’re open to the so-called day trippers.

Also See Trip Planner/Takaragawa (PDF)

We chose a Tuesday to avoid the weekend crowd, driving from Jomo-Kogen Station along the river atop forested roads. The parking lot was empty, a good sign as we each paid our 1,500 yen (around 810) entrance fee. We declined the 200-yen hand towels because we’d brought our own, and reassured the woman at the ticket booth that we knew the rules. Japanese are very particular about their bath etiquette, careful to wash and rinse completely before entering the bath so in effect you’re clean before you start! No swimsuits, please. And enjoy.

Getting to the baths can be a bit surreal. After passing through the restaurant and souvenir shop, the pathway down to the river is filled with curios and antiques, some of it more like junk, including large tengu (mythological creatures with long noses) masks, dusty laughing Buddha statues, straw snow boots and old flags, a collection that had expanded since my last visit seven years ago.

Then you pass several cages housing six black bears, leaving you wondering what the exact connection is between hot springs and bears. They’re also in small cages. Signs in English and Japanese explain that they are orphans rescued from the wild.

After a few hundred feet of such distractions, you reach the entrance of the large co-ed bath, one of four in the complex, and a petite building with small male and female changing rooms— essentially rectangular baskets on open shelves where you leave your clothes. There are also lockers, but the Japanese are honest. I quickly wrapped myself and my seven-year-old daughter in bath towels and went looking for the shower stalls to pre-clean ourselves, but the facilities here are rather basic, limited to a couple of stone outdoor wells with cold and hot running water. We rinsed as best we could and headed to the mixed bath.

My husband and son were already there—what is it about guys flying out of bathrooms so quickly?—having strategically covered themselves with small white towels as had the other male guests, while most women used bath towels. Male guests, most in their 20s and 30s, outnumbered their female counterparts, perhaps because Japanese women are becoming more shy about co-ed bathing.

The water felt a little hot at first, though I soon got used to it as I waded to the middle of the metre-deep pool to enjoy the idyllic surroundings. The large main pool is paved with dark rocks in a setting of natural stones and maple trees on three sides, the fourth enclosed by an impressive wooden pavilion, making it the most scenic of the four baths.

Right next to the bath is the fast-running, gurgling Takaragawa river, its sounds mixing with the songs of cicadas— serenity at its best. People say the fall is especially stunning here when the maple leaves erupt in reds and yellows.

In Japan, there are reportedly over 20,000 hot springs, more than anywhere else in the world, a byproduct of Japan’s location in an earthquake belt. Under the influence of Shintoism, the Japanese believe water is a purifier that cleanses and heals body and spirit. Small wonder that onsen have become a multi-billion dollar industry with towns squabbling over hot water rights and oil drill experts employed to find new hot water sources. In old days, hunters sought out their favourite hot spring after an arduous hunt, as would warriors to tend to their battle scars.

As the hot water did its magic, I closed my eyes and imagined myself a samurai. After a while, I took short breaks strolling to the other baths secreted in the rocks, each with different temperature and vista. There’s even a well-secluded women’s-only bath where women go in and out naked— something that may intimidate the uninitiated.On the paths, graceful Japanese ladies strolled in red and blue yukata (a casual, summer garment made of cotton that resembles a kimono) resembling a scene from an old painting, if it weren’t for their latest models of cellphones.

As we headed back to change, I ran into a Filipina lady who, speaking in Japanese, told me she was trying out the hot spring for the first time with her Japanese boyfriend. Nearby was a European couple soaking gingerly in the main bath contentedly, evidence the spas long known by Japanese are gaining reputation among foreigners.

On our way out, I caught up with Takeo Ono, the hotel and onsen manager, who said some 60,000 people visit annually, 5% of whom are foreigners, with the number of European visitors, especially Spaniards, having spiked recently. “Two years ago, we had a bit of an uproar when three Spanish women decided to enter the mixed baths stark naked with two of their companions," he said. “We got quite a bit of press after that, which no doubt sparked European interest."

Sure, outdoor bathing for Japanese is about being one with nature, he added, and for some, it can be like a spiritual journey, but he welcomed international guests who might simply want to relax.

As we drove away from Takaragawa and its beautiful surroundings, our daughter said how much she’d enjoyed it and asked whether we’d be back soon. “I’d be here every day if I could," I said, vowing that it wouldn’t take us another seven years to return.

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