If you can accept its gimmickry and brazen commercialism, the glitzy, neon-lit hot spring resort of Beppu, a melange of pachinko parlors, love hotels, sleazy bars, night clubs and hot baths visited by over 12 million tourists a year, constitutes an amazing thermal and entertainment roller-coaster.

The boiling surface and mud deposits of Blood Pond Hell (above), one of the Kannawa Jigoku, and the grand entrance to Takegawara, an original Meiji Era bathhouse.

Willard Price, in “Journey by Junk,” his engaging, thoroughly exaggerated account of traveling through the region, wrote that Beppu was “built upon the roof of the infernal regions — stamp too hard and your foot may go through the thin crust and come out parboiled.” The earth does seem unusually brittle here, and with reason.

The city’s porous skin is punctured by an infinite number of vents from which steam continuously rises, making it feel at times like a huge, malfunctioning boiler room, all its valves and pipes threatening to burst at once. Scalding water surfaces not only at Beppu’s 3,000 or more water sources and over 160 bathhouses, but is also piped into private homes where it is used to heat rooms, fuel brick and stone ovens and warm up greenhouses. The intense geothermal activity contrasts with a leisurely atmosphere and pace typified by the sight of carefree Japanese and foreign tourists strolling around the streets of Beppu in their yukata (light cotton kimono).

Beppu offers some interesting variations and twists on the simple theme of a hot bath. Visitors can soak in a series of baths of graded temperatures, plunge into thermal Jacuzzis or have themselves immersed up to the neck in steaming mud. At certain times of the year bathers soak in water made fragrant by the addition of orange peel or segments of yuzu (citron) placed in floating bags.

Most of Beppu’s sights are connected in some way with the hot springs. The most celebrated are its Jigoku (Boiling Hells), pools of mineral-colored water and bubbling mud. A circuit of the Nine Hells, seven of which are located in the Kannawa district of Beppu and within walking distance of each other, reveals each pit with a different function, color and mineral property.

The waters of Umi Jigoku (Sea Hell) are the color of a tropical ocean; Chi-no-Ike Jigoku (Blood Pond Hell) is a highly active pool whose color derives from dissolved particles of red clay that provide the ingredients for an apparently highly effective skin ointment; Oniyama Jigoku (Devil Mountain Hell), on the other hand, is the unlikely breeding ground for crocodiles. Bozu Jigoku, also within the Kannawa group, takes its name from the supposed resemblance of its boiling surface and mud bubbles to the head of a bozu (monk) who once served at a temple here. According to the story, a nasty cautionary tale, an eruption directly beneath the floor of the building tossed the monk into the air, before landing him in the seething caldron.

Subtropical gardens often luxuriate around these boiling hells. The gardens at the edge of the life-withering pits appear to be nourished rather than brutalized by contact with pools seething with radon, sulfur, iron and magnesium. The lusty palms that grow in botanical profusion, the giant lily pads at Umi Jigoku and the bonsai pines seem to flourish in the steamy air, even when wreathed in jets of humid, white cloud.

Many of the baths are attached to hotels but are also open to the public. For high kitsch, color and hilarity, the phenomenally popular Suginoi Palace is an irresistible Angkor Wat-meets-Disneyland hot spring fantasy. Connected to the Suginoi Hotel, this mammoth hot spring is divided into two areas called the Flower Public Bath and the Dream Public Bath. Both are decorated with tropical plants and feature such novelties as sand and saltwater baths, water chutes for kids, wave pools and revolving Buddhas. U Zone, an electronic game center with a plastic-ice rink and other amusements, is within the same complex.

Beppu’s sunaburo (sand baths) are less publicized than those at Ibusuki in southern Kyushu, but also less commercialized. At the Beppu Sand Beach Bath, a sign in Japanese and Hangul stands outside on the busy main road that bathers try not to notice when they are being covered in heaps of sand. The roar of traffic spoils the awaited bliss somewhat, like the spurs of concrete tetrapods, crude water breaks, that also block a view of the horizon. There are two sand pools here, one of which is drained and left to infuse the rising steam and heat and to be used for the “bathing,” while the other is allowed to flood again until the second frame is used.

Although the beach offers the same service alfresco, Takegawara Bathhouse, one of Beppu’s oldest bathing experiences, is by far the more atmospheric way to enjoy a sand bath. It is a grand Meiji Era building dating from 1879, and most of the original fittings and fixtures — time-worn wood and tile floors, sunken baths, banisters topped with bronze finials, soaring wood pillars, a roof as high a church — remain intact. Everywhere you look, there are timepieces from the last century, large grandfather clocks and round or oval white-faced pieces like giant wristwatches framed in walnut.

Entering the sunaburo is a little like disturbing a group of grave robbers at work. There are three or four figures in the gloom, vigorously disinterring a man from a burial mound of black earth with shovels. The surprise passes quickly. The figures turn out to be elderly matrons in blue smocks, the “corpse” a much-resuscitated local resident who comes for a sand bath once a week.

When you’re fully covered in the sand, the substance feels more like black grit, something that could be used for construction work, road undersurfacing, perhaps. This is quite different from the childhood novelty of being buried by your brother or sister on the beach. It is also, in its own way, far more invigorating. In fact, it’s the best of all possible places to end the day.

In line with COVID-19 guidelines, the government is strongly requesting that residents and visitors exercise caution if they choose to visit bars, restaurants, music venues and other public spaces.