Misasa Onsen

The bus from Kurayoshi Station takes about twenty minutes, following a river road that narrows as the valley closes in around you. Misasa is a small town on the Mitoku River in inland Tottori, and it announces itself before you see it. The air changes. There is a faint warmth and a mineral undertone that people here will tell you is the radon, though you cannot smell radon, exactly. What you can smell is something older and earthier than that, like hot clay after rain. You step off the bus and there, running right through the middle of the shopping street, is the river itself, with a free outdoor footbath built along its stone bank where locals and travelers sit together in the open air.

The water at Misasa contains some of the highest naturally occurring radon concentrations recorded anywhere in the world. It is a radium spring, pH 7.2, and the water is completely transparent with no particular color or strong smell in the indoor baths. What distinguishes it is the feel. It is softer than ordinary water, slightly silky, and when you have been in it for ten minutes your skin begins to feel warm well beyond where the water actually touches. Locals call this the "three mornings" effect, from the name Misasa itself, which is said to mean that three consecutive morning baths will wash away whatever ails you. Drinking the spring water from the public taps along the town's main street is also customary, though the taste is faint and slightly metallic.

The single most striking thing about visiting Misasa is the statue of Marie Curie in the small park at the center of town. She stands in bronze looking genuinely pleased with something, and the reason she is here is not abstract. Scientists once measured the radon levels in the air around Misasa's springs and found them significantly elevated compared to surrounding areas. Researchers subsequently linked long-term exposure to the low-level radioactivity to unusually low cancer rates in the local population, and the town became a subject of serious medical study. Curie, who gave her life to the study of radioactivity, became the town's unlikely patron, complete with an annual Curie Festival each July.

Above the town, a thirty-minute bus ride up the mountain, is Mitokusan Sanbutsuji temple, one of the genuinely strange buildings in Japan. Its main hall, Nageire-do, was built into the mouth of a sheer cliff face roughly nine hundred meters up the side of Mount Mitoku. The route to reach it involves climbing chains bolted into bare rock, and visitors are turned away if they are wearing anything without grip. In 2015, the Japanese government recognized Misasa Onsen and Mitokusan together as a Japan Heritage site, linked by the ancient concept of purifying the body before approaching the sacred. Soak in the radium water at the river bath in the morning, then climb the mountain in the afternoon, and the designation starts to make a certain kind of physical sense.