Myoban Yunosato Onsen

Beppu station sits right on the edge of Beppu Bay and the streets immediately around it are dense with hotels, arcades, and the ordinary machinery of a busy Japanese city. But take a taxi or local bus about twenty minutes uphill into the Myoban district and the city falls away. The hillsides here are dotted with wooden structures that look almost agricultural at first glance. They have low, rounded thatched roofs and no windows to speak of, and thin threads of steam leak from their eaves in all weather. These are yugoya, steam huts, and they are doing something that has been designated a national intangible folk cultural asset. Inside them, sulphur crystals called yunohana are slowly growing on the clay floor, produced by the geothermal vapour rising through the ground, accumulating at roughly one millimeter a day before being harvested and dried over forty to sixty days.

Myoban Yunosato Onsen is set among these huts. The water here is acidic sulphur with a pH of about 2.2, and the baths are a striking milky blue-white that shifts toward pale grey depending on the light and the time of day. The sulphur smell is strong and immediate when you approach the outdoor pools, the kind of sharp eggy note that reminds you the earth is doing something serious underfoot. When you enter the bath the water feels soft on your skin at first, then develops a faint tingle that is the acidity doing its work. The water is hot, the steam rises fast, and the combination with cold mountain air makes the outdoor rotenburo feel like something you could sit in for half an hour without noticing.

The visual moment that stays with you is the sight of the yugoya from the bath itself. You are sitting in steaming blue-white water with your back to the hillside and the thatched roof structures ahead of you, wisps of steam curling from every joint and gap. It looks like a scene from a Japan that existed before electricity. The huts have been maintained in essentially this form since the Edo period, and the production method for yunohana has changed almost nothing since the 1600s. The crystals collected from the Myoban district are sold throughout Japan as bath salts, which means there is a good chance that unremarkable drugstore onsen tablet in your bathroom cabinet came from a hut on this hillside.

Myoban sits within Beppu's eight distinct spring zones, known collectively as Beppu Hatto, but it has the most particular visual identity of any of them. The mixed bathing option available at some of the pools here is one of the few remaining places in Beppu's history where rotenburo were genuinely communal rather than segregated. Getting here from central Beppu takes effort, and most tourists do not make the trip up the hill. That is their loss. The walk among the steam huts before you even change into your bathing clothes is worth the bus fare by itself.