Shiraike Jigoku (White Pond Hell)

Shiraike Jigoku, the "White Pond Hell," is the most understated and elegant of Beppu's seven hells. Where its neighbours roar, bubble and blast, Shiraike simply glows - a broad pond of pale, milky blue-white water sitting placidly within a carefully composed Japanese garden of pines, stone lanterns and clipped shrubs. The water emerges from the ground colourless and clear, but as it cools and its pressure and temperature drop, dissolved minerals precipitate out and turn it the soft opalescent white that gives the hell its name.

The result is one of Beppu's most photogenic scenes, and a deliberately calming one. The garden setting invites a slower pace than the crowded Umi Jigoku or the crowd-pleasing Kamado; benches and shaded paths encourage visitors to sit and take in the interplay of steam, water and landscaping. In autumn the surrounding maples turn, framing the white pond in red and gold, while the year-round steam lends the garden a dreamlike softness on cool mornings.

Behind the pond lies Shiraike's quirkiest feature: a small tropical aquarium heated entirely by the geothermal steam. Because the springs provide free, constant warmth, the aquarium can keep species that would never otherwise survive in the cool highlands of Kyushu, including red-bellied piranhas and the giant Amazonian arapaima (pirarucu), one of the world's largest freshwater fish. Standing in a mountain onsen town looking at piranhas kept alive by volcanic heat is a small, surreal delight that captures the resourcefulness with which Beppu has always harnessed its underground energy.

Shiraike is one of the five walkable Kannawa hells, sitting a short stroll from Kamado and Oniyama, and it shares in the national Place of Scenic Beauty designation that covers all seven. Its compact size means most visitors spend only 20 to 25 minutes here, but its garden atmosphere makes it a pleasant place to slow down partway through the hell tour, especially after the sensory overload of the more dramatic sites.

The pond's colour is subtle and light-dependent: bright, indirect daylight brings out the milky blue most clearly, while flat or overcast conditions can make it read as plain grey-white. Photographers do best on a clear morning, using the garden's lanterns and pines as foreground framing. The steam is heaviest in cold weather, so winter visits trade colour for atmosphere.

Facilities are modest but sufficient - restrooms, a small shop and the aquarium - and the garden paths are largely flat with a few steps, making Shiraike reasonably accessible. It rarely feels crowded compared with the headline hells.

For many visitors Shiraike is the quiet highlight of the Kannawa cluster: proof that Beppu's geothermal spectacle is not only about violence and heat but also about beauty and stillness. Between the milky pond, the manicured garden and the improbable tropical fish, it distils the strange, inventive charm of a city that turned scalding water into a centuries-long art form.