I Stripped Down for a Bath in Japan's Sulfuric Hot Springs — Here's Why You Should Too

In Japan, home to tens of thousands of mineral-rich onsens (hot springs), hydrotherapy isn’t just an occasional indulgence—but rather a way of life. I tried to remember this as I descended into what smelled like a pile of rotten eggs at Noboribetsu, a ski resort set on a crater in the country’s northernmost prefecture of Hokkaido. Noboribetsu has several hotels, including Dai-ichi Takimotokan (takimotokan.co.jp; doubles from $227), where there are seven different pools for all sorts of ailments. Rich in sulfur, the bihada no yu, or “beautiful skin bath,” is said to expand capillaries in your arms and legs and improve your complexion. The alkaline water felt soft, like easing into expensive sheepskin slippers.

Bathing culture holds strong in many parts of the world, from Scandinavia to Russia, but it wasn’t until I moved to Okinawa, in the far south of the country, that I understood its primacy in Japan. Escaping to an onsen on the weekend is a quintessentially Japanese pastime. There are more than 27,000 of them throughout the country, the result of tectonic and volcanic activity that produces geothermal waters.

To be officially classified as an onsen, the water must exceed 77 degrees Fahrenheit and contain at least one of 19 designated minerals, each offering a particular promise of good health. The benefits of hot baths, from their anti-inflammatory properties to their calorie-burning qualities, are well-known—there’s even a branch of traditional medicine, balneotherapy, dedicated to their healing powers. Now, wellness enthusiasts, increasingly attuned to the physical and spiritual advantages of taking the waters, have become more interested in this centuries-old Japanese tradition.

Professor Yuko Agishi, balneologist and professor emeritus at the Hokkaido School of Medicine, has outlined three benefits of hot springs. First are the effects of heat on the body, which Agishi says increases the production of hormones and stimulates the immune system. Second is the effect of the minerals. Sulfur, as I now know from Noboribetsu, gets the blood pumping; sodium may cure bronchial disorders and diabetes; calcium is good for stomach maladies and allergies. To see dramatic benefits, however, balneologists caveat that onsen treatment should be thought of as a lifestyle choice, not a quick fix, which brings us to its third benefit: psychological well-being.

At Noboribetsu, I saw how Japanese visitors, especially older ones, dedicated their entire day to the bath. They would arrive at breakfast with soaking hair and sandals, and in the evenings look exactly the same. As a novice, I didn’t find spending that much time in the steam especially appealing. Instead, I’d hike in the national park next to the crater or seek out a ramen shop for lunch, then retreat to my hotel’s bath complex before dinner. It was not, by any means, an especially active trip, but my daily dip left me feeling as accomplished and invigorated as if I’d climbed a mountain.

Zaborin Ryokan, in Niseko, is set in the Hanazono woods.
Zaborin Ryokan, in Niseko, is set in the Hanazono woods.

For the Japanese, there is also the comforting component of ritual to the onsen retreat. Although there are public, open-air hot springs, the traditional way to visit the baths is to stay at a ryokan. These Japanese inns are set up as they have been for centuries: tatami mats, floor cushions, and, tucked away until sunset, futon beds. Those located near hot springs pipe in water for indoor bathing; sometimes, it’s only through the ryokan that a bather can gain access to an outdoor hot spring. On check-in, guests are given a yukata, or belted cotton robe, which they wear everywhere.

Najimu, a word for the pleasant dynamic that develops when sitting in quiet communion, as at an onsen, means “to become accustomed to.” It entails a stripping away of layers both social and physical. A studied nonchalance about nudity prevails, codified via a system of unspoken rules, which can be intimidating.

The first time I went into the women’s locker room at Noboribetsu, I watched what others did and thought I was getting it right, starting with a shower to scrub away outside dirt. An elderly lady approached me and gestured at the large towel I was carrying into the bathing area. This was for afterward, she indicated, back in the changing area. While moving between baths, the only permissible drying implement is a small hand towel.

Related: The Best Japanese Ryokans for a De-Stressing Getaway

Though I enjoyed the low hum of conversation in the big bathing complex, I was eager to soak in my own private tub. About two hours northwest of Noboribetsu, in the resort area of Niseko, is Zaborin (zaborin.com; villas from $1,410), considered one of Japan’s finest ryokans. The journey was not easy: I drove on snow-covered roads through remote villages, dipping in and out of cell service, occasionally thwarted by a fallen tree. But arriving at Zaborin, in a secluded pocket of the Hanazono forest, felt like a return to a platonic ideal of the country. On check-in, guests are greeted with a tea ceremony and given an ash-gray linen yukata. I noticed the wood underneath my toes was warm; the staff explained that hot springs powered the underfloor heating.

Each of the 15 private villas has two private baths: stone outside, cedar inside. The spring water is rich in magnesium, said to have a sedative effect, as well as calcium, good for suppressing inflammation. Each night I’d fall asleep to the soft trickle of water from the indoor bath. In the morning, I’d sip green tea in the outdoor tub and watch the snow blanket the trees before heading down for a breakfast of firm local tofu topped with bonito flakes, steamed river fish, and pear juice.

Snowed in for three nights, there was thankfully very little to do other than pad around the thoughtfully curated library and, of course, take multiple baths. Despite its dense mineral content, the water was surprisingly transparent. Even as a faithful user of high-tech serums, I had to admit that upon leaving Zaborin, my skin had never seemed so clear, so weirdly pore-less. I also left with a memory of being suspended in the hot waters of the stone tub on the balcony, watching the snow fall on birch trees. In that moment, I felt a peace that will be hard to re-create.