For a brief moment, I feel like a Japanese snow monkey -- those furry, red-faced creatures that descend from the cliffs and forests of Nagano to sit and soak in hot spring water. Flakes fall around me. Steam drifts into the air. I’ve nothing much on my mind. It’s after 7 a.m. and I’m tout nu inside a private bath on a terrace at Arcana, a boutique hotel hidden in the trees of Japan’s Izu Peninsula. The setting and time of day conspire to make me feel as though I’m the only one in the world who’s awake. The multi-colored canopy is dusted with frost and snow. The ceaseless soundtrack of the rushing river below is overlaid with the chirps birds make as they chase each other from branch to branch. The wind rustles the smooth stalks of bamboo that stand nearby. So many sights and sounds to take in, but the heat of the mineral-rich, geothermal water trumps them all. The Japanese call hot springs "onsen," but they also use the word to describe the spas and bathing facilities that are found in every corner of this country, from tiny shacks to traditional inns to upscale retreats. “Onsen in Japanese culture is very important in our daily lives,” says Dr. Yuko Agishi, a leading researcher on the health benefits of onsen. “Especially when it comes to relaxation and stress relief.” It’s something Japanese people (and monkeys) have been enjoying for centuries. And whether the onsen is private or public, gender exclusive or mixed, the principle remains the same: bathers shed their clothing, wash their bodies and then wade into the hot, sometimes cloudy water to commune with others or sit in quiet contemplation. “Onsen also foster the egalitarian ideal for which Japan prides itself,” explains Duff Trimble of the Toronto-based travel agency Wabi-Sabi Japan. “Once you are in the baths stripped of all material possessions, everyone is equal.” Wealth of water A wealth of hot spring water is pooled deep below the surface of this volcanic archipelago, which is made up of more than 6,800 islands. The stories of how some onsen were discovered, anywhere from hundreds to nearly 3,000 years ago, are just as rich -- injured birds unwittingly teaching people about the healing powers of the hot water, warriors recovering from their wounds after a long soak, gods guiding samurai to springs purported to cure 40,000 different types of illnesses and disorders. During my trip to Izu, I watch people pose for photos in front of the original source of the Shuzenji onsen, the oldest on the peninsula. According to legend, a Buddhist monk encountered a boy bathing his ailing father in the Katsura River in 807. So concerned was he that the cold water would worsen the man’s condition, he thrust his dokkosho (a ritual instrument) between the stones in the river, releasing a hot spring that eventually cured the boy’s father. He then taught the locals about the benefits of balneotherapy -- the treatment of disease with baths. More than 1,200 years later, the lessons are embedded in the Japanese psyche. “It’s good for my health,” explains Hisako Sugiura of Nagoya, a 65-year-old who has visited onsen on the northern island of Hokkaido, the southern island of Kyushu and points in between. “I go to onsen 20 times a year,” says 73-year old Toshimi Ishiyama, who came to Shuzenji with three friends from the Tokyo area. “It's good for the body.” Just a short walk away from the crowds, I happen upon Koko Omura, who’s spent the better part of an hour sitting quietly with her feet immersed in a foot bath, reading a magazine and thinking about how her life will soon change. The Tokyo resident has returned here to her hometown to be with her parents. She’s having a baby in two weeks. “I’m supposed to keep my body warm before I give birth,” she notes, her hand absently stroking her belly. “It’s good for the baby.” Soaking up the health benefits Japanese scientists have been documenting the positive impact onsen can have on human health since the early eighteenth century. Dr. Agishi’s decades of studies have shown that hot spring water, depending on its mineral composition, can help people recover from certain surgeries and control a number of conditions, including rheumatism, neuralgia, hypertension and skin diseases. “There is a physiological mechanism of keeping the body temperature warm by some kinds of hot springs that differs from plain tap water,” explains Agishi. And if you look at the statistics, it’s clear the Japanese understand that difference. Agishi says the total number of people who visited an onsen in 2010 was nearly 128 million. “This means that, on average, every Japanese spent more than one day in an onsen.” Or more than that, if you consider people like Toshimi Ishiyama and the tiny woman I meet on the way to the no frills Kajika-no-yu onsen in Izu’s Amagi area. “Doko ni ikimasu ka?” I say, asking the 90-year old where she’s headed as she slowly pushes her walker along the road. “O-furo,” she replies softly, which, meaning “bath,” is another word for onsen. Onsen knockoffs So revered is the bathing practice that setting up temporary public baths in Japan’s ravaged northeast was on the list of priorities in the days after the March 2011 disaster. In Tokyo, some hotels try to give their guests access to the onsen experience, even if it’s only symbolic. The Park Hyatt’s spa features a large bath heated to 40 C, along with a nearby plunge pool that’s set to a skin-tightening 20 C. The Four Seasons goes a step further. Its property in Marunouchi has a system that infuses normal water with radium ions, known to be effective for lowering high blood pressure and preventing hardening of the arteries. But onsen that bill themselves as the real deal must adhere to strict guidelines. Japanese government officials regularly check spas to make sure they comply with the country's decades-old Hot Spring Law (onsenhou), and crack down on rule breakers. They recently caught a handful of onsen in the Gunma and Nagano regions that were using tap water or meddling with the mineral composition of the spring water. It's a reflection of just how serious the Japanese are about onsen. People in this country can be very particular about where they bathe, often selecting their hot springs based on the documented healing properties of the water: iron-rich springs for painful joints, sulfur to control blood pressure and prevent hardening of the arteries and hydrogen carbonate for smooth skin (to name just a few). Tourists also have an appreciation for the baths. Canadian Tim Richards and his husband, Francisco Ortiz, spent a chilly December night at an onsen in Hakone, a popular resort area southwest of Tokyo. “We’d been freezing,” says Richards of his trip. “Then we went into the water and we were so warm. Francisco went to bed and he was still sweating.” Can’t-miss experience Deep inner warmth and relaxation. Pain relief and smooth skin. Onsen often leave an immediate impression on visitors to Japan, but it’s the experience itself that endures. I’ll never forget that cool June evening in Kawayu Onsen when I immersed myself in the hot spring water that can be found simply by digging a hole in the rocky bank of the Oto River. Or that crisp November morning dip at the Hoshinoya onsen in Karuizawa when I watched a toddler with a tiny Buddha belly gather bouquets of fallen leaves for her father as the mist curled into the air and then disappeared. Or this moment, here at Arcana in Izu, with the bamboo swaying in the breeze, the snow falling lightly and whiffs of wood smoke filling the air. I tilt my head back and pinpricks of cold dot my face. Below the surface of the water, my body bakes. Pretty soon, I’ll be on a train speeding toward Tokyo. I do my best to savor every second of this final soak. Sometimes when we travel, there are cultural practices and customs we just don’t get. The Japanese onsen experience definitely isn’t one of them.