Hot springs and healing waters in Japan's onsen capital
Onsens are woven into the fabric of society in Oita, a Japanese region where the red-hot water bursting from the ground is harnessed into pools of all shapes and sizes, and the mountains that provide it are revered and respected.

Wooden walkways extend over an onsen in Beppu in Japan's Oita region.
Steam rises slowly from Mount Garan, billowing from holes in its side as if a seething, fire-breathing beast lurks just beneath the earth. It’s early, and our only company on this weathered path has been a couple of Japanese nightingales, their plumage grey, the colour of rain.
“They herald the coming of spring,” my guide, Yume, explains. “Listen to their call, it’s iconic.” I train my ear for the sound, and as if aware of an audience, a cacophony of birdsong bursts from a nearby cedar. Yume laughs, clapping her hands together: “The sound fills everyone here with joy,” she says. “But come, we’re not here for the birds.”
In fact, we’re heading to Tsukahara Onsen, one of the most famous in Oita (for a region known as Japan’s hot spring capital, that’s saying something). Located in the north east of Kyushu island, Oita is dotted with active volcanoes. Fault lines running beneath these mountains form channels of boiling magma that heat subterranean water to over 1,000C, before pushing it upwards to explode from the Earth’s surface.
“We have the highest number of hot spring sources in all of Japan,” Yume reveals proudly, “and this one has the thickest mineral content of them all.” We smell the pool before we reach it — a pungent odour of gone-off eggs, but one that, I’m assured, only proves the healing powers of the water. The minerals in onsens, it’s said, can alleviate health problems as varied as asthma and arthritis; they’re so concentrated in this particular spring that bathing for more than 20 minutes is forbidden. After just a few minutes, my skin starts to tingle. I towel myself dry, admiring the simple stone pool and wondering aloud when man learnt to harness these red-hot eruptions of water and steam.
“No one knows exactly,” Yume tells me, “but records show the idea of bathing may have been introduced by Buddhist monks from China in the 17th century, and it didn’t take long before it became a huge part of local life.”
Sitting at the base of the mountain, Beppu is an excellent example of the extent to which hot springs have been woven into the very seams of society. A small city of sloping roofs and billowing steam, there are onsen everywhere, from foot baths hidden beneath restaurant tables to private pools in hotel gardens. Wastewater running through underground pipes here is so warm that tropical fish have made a home in them — unwanted pets that thrived after being freed, so the story goes.
In the city’s leafy Kannawa district, Asako greets us at the entrance of her traditional Japanese lodge, Futabaso, where guests occupying the 10 rooms often stay for many months, taking daily onsens to help with various ailments and enjoying her excellent cooking. An enormous well dominates a central courtyard, pumping mineral-rich water to several small pools, and an elderly man wearing a perfectly pressed yukata (robe) nods to us as he passes by, heading for his afternoon bathe.
Asako has worked here for 50 years, and the lodge is twice as old again, the worn furniture and cracked walls only adding to its charm. Between boiling eggs (in onsen water, naturally) and stripping bananas for her evening dessert (“the water makes them sweeter”), she tells us a bit about herself. “I believe in the power of mountains,” she says. “It’s why my work has always revolved around onsens; they’re a constant reminder what Mother Nature can provide.”
Asako practises Shugendo, a blend of Shintoism and Buddhism; it’s a faith in which mountain worship is fundamental. Whether religious or otherwise, this power is tangible in Oita, a pulsing energy rising from deep below the Earth’s surface evident in the hot springs scattered across the region.
“They’re an ancient force far beyond any of us and must be respected,” Asako continues, gesturing towards the row of peaks just visible through her rice-paper screens. Among them, high above the scurryings of human existence, Mount Garan steams broodily, just as it’s done for centuries, oblivious to the people on its paths, to the seasons’ change or to the nightingale singing for spring.
Umi Jigoku, the blue-hued volcanic spring in Beppu, Oita.
A guide to onsen etiquette
Birthday suits only
While this may sound a little disconcerting, don’t be put off by going in naked: no one bats an eyelid and it’ll soon become liberating. If it really isn’t your thing, some inns offer private onsen hire, and upmarket hotels do sometimes provide special bathing towels you can wear in the water.
Wash before taking a dip
Washing in the bath is a no-no in Japan, and all onsens will have showers and stools around their perimeter. Be advised that it’s important to be sitting down while you do so; having a scrub down standing is considered very bad manners.
Follow towel etiquette
All onsens will provide patrons with both a small and a large towel (either free or for a small fee). Don’t confuse the two; the larger is for drying yourself with after you’ve bathed and must stay in the changing room; the smaller is more like a flannel and can be taken into the onsen with you. These can be useful for covering your modesty, just don’t hold them underwater. In fact, many people balance them on their heads while taking a dip.
Cover up tattoos
Tattoos are a taboo in Japan — partly due to their association with the yakuza (organised crime syndicates). It’s generally not a problem if they can be covered by a plaster, but if not, renting a private onsen may be the way to go.
Published in the May/June 2020 issue of National Geographic Traveller (UK)
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