Whether it is a visitor’s first time in Japan or their 50th, some experiencescannot be overlooked. Top of that list for many people is a long, relaxing soak in one of the nation’s “onsen” hot springs.

Found virtually the length and breadth of the country, onsens range from simple riverside pools that are natural catchments for scalding water forced to the surface from hundreds of metres underground to glitzy hotel complexes built atop vents, complete with elaborate facilities and après-soak entertainment.

Frequently, the best onsens are off the beaten track – which makes relaxing after the effort of reaching the destination all the more enjoyable.

Tsuruya is a classically designed “ryokan” in Fukui Prefecture, on the northern coast of the main island of Honshu, that first opened its doors in 1884. The town of Awara has for generations relied upon its reputation for hot springs, whichhas spread to foreign visitors.

The hotel rooms have tatami-mat floors, sliding paper doors, “ikebana” flower arrangements and calligraphy scrolls decorating the “tokonoma”. Guests sleep on fluffy futons laid out on the floor after a sumptuous evening meal of locally caught fish and crab, accompanied by mountain vegetables, miso soup and excellent sake from a nearby brewery. But the onsens are the highlight of any stay.

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Beyond “noren” curtains – red for the ladies and blue for men – are changing areas that lead into a stone-floored washing area with an L-shaped pool that steams in the subdued lighting. Beyond a glass door is an outdoor pool large enough for half-a-dozen folk, overlooking a traditional walled garden, complete with moss-covered rocks, a stone lantern and Japanese maple trees that shed deep red leaves in the autumn.

Visitors can reserve a private onsen for up to an hour, with the square pool again looking out across a carefully tended garden.

Further north, towards the tip of the Noto Peninsula in Ishikawa Prefecture, is the sprawling and modern Kagaya in the coastal town of Wakura.

First recognised for is therapeutic powers more than 1,000 years ago, the water at Kagaya comes from a saline spring that passes through a layer of granite far below the surface and is known locally for alleviating ailments such as bruises, arthritis and neuralgia.

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Women visitors can enjoy the view across the bay from the indoor Kashin Bath, with a colourful tiled roof and long pool, or the outdoor Benten Bath, which is ringed by large rocks and roofed in bamboo.

Men have baths on three floors to explore, including the stone-floored Ebisu Bath, from where the sunset is spectacular.

After that therapeutic soak, hotel guests are able to enjoy shows by musicians and dancers, the bar and shopping.

The newest addition to the selection of hot springs is scheduled to reopen at the refurbished KAI Alps ryokan, part of the Hoshino Resorts company, on December 21. Deep in the mountains of Nagano Prefecture, the hotel was closed in March 2016 for nearly two years of renovations designed to allow visitors to “experience the healing and rejuvenating hot springs of the Nagano countryside”.

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The property will have indoor and outdoor baths, offering views across larch forests with mountains in the background. The spectacular views change with the seasons, from snow-covered peaks in the depths of winter through the bright and fresh greens of spring, the stillness and deeper colours of summer and eruptions of reds, golds and russets that mark a Japanese autumn.

The resort is convenient for the Hakuba ski resort slopes, the perfect place to work up an appetite for the local cuisine and, later, to get the kinks out of the muscles with a spell in the onsen.

An altogether different hot spring experience can be enjoyed on Yakushima, the Unesco-listed World Heritage island to the south of Kyushu.

The Hirauchi seaside onsen is among a clutter of rocks that are submerged at high tide, restricting accessibility to four hours a day.

The onsen is small and open to men and women, with anyone wanting to test the water must donate 100 yen (HK$6.87) in a box and leave their clothes in a neat pile. There is no changing area so visitors should bring a towel.

Once immersed, however, the steam rises in tendrils and the only sound is of the sea crashing against the nearby rocks and the occasional gull riding on the thermals above.