The hells

The town sits on the flank of a volcanic caldera on the north-east coast of Kyushu. Rainwater sinks, meets heat, and comes back up — everywhere, continuously, in more chemical varieties than almost anywhere on earth. Beppu City counts seven different types of spring water in its own springs.

Why "hells"

Some vents are far too hot and too chemically aggressive to bathe in. For most of history these were places to avoid, and people called them jigoku — hells. Nearly 1,300 years ago, the Bungo Fudoki of the 8th century records them as a hazard, not an attraction.

Seven of them are now a paid circuit, and they are genuinely different from each other:

Umi Jigoku — "sea hell" — is cobalt turquoise, and the colour is dissolved iron sulphate, not a dye. It is around 98°C. Chinoike Jigoku — "blood pond hell" — is deep red from iron-rich clay and is documented as the oldest natural hell in Japan. Tatsumaki Jigoku is a geyser that erupts on a roughly half-hourly cycle, with a stone slab placed over it to keep the jet down for safety.

Four of the seven hells — Umi, Chinoike, Shiraike and Tatsumaki — were designated National Places of Scenic Beauty in 2009. This is a town where the geology is legally a landscape.

What to actually do about it

The hells are for looking at. The bathing happens elsewhere and is the better half of Beppu.

Takegawara Onsen, in a wooden building from 1879 rebuilt in 1938, offers the sand bath: you lie in a shallow trench in a yukata and attendants shovel geothermally heated sand over you until only your head shows. Ten minutes is the recommended limit. It is heavier than you expect and the sensation of the weight is the point.

At Myoban, up the hill, thatched huts sit over vents where mineral crystals — yunohana — are grown on straw beds over months and scraped off. The technique dates to the eighteenth century and is a designated Important Intangible Folk Cultural Property. You can buy a bag and turn a bathtub anywhere into this.

And you can cook in it

At Kannawa, the district where the steam is thickest, the Jigoku Mushi Kobo lets you buy raw ingredients, put them in a basket, and lower them into a stone steam vent. Vegetables take ten minutes, seafood a little more. The steam is around 100°C and slightly salty, and it seasons the food as it cooks.

Local families have cooked this way for centuries, and some houses in Kannawa still have a steam box in the kitchen.