Kamegawa Onsen District

Kamegawa Onsen occupies the northern, seaward edge of Beppu Hatto, and its defining feature is its relationship with the coast. This is a district of the shore rather than the hills, and its signature experience is the sunayu - a hot sand bath in which attendants bury you up to the neck in black volcanic sand heated from below by geothermal springs. At the Beppu Kaihin Sunayu, the sand-bath facility sits right by the water, so bathers lie warmed by the earth while looking out toward the sea, a sensation quite unlike an ordinary hot-water soak. The weight and even heat of the sand are said to boost circulation and ease aches, and the whole ritual, gown and all, is one of Beppu's most memorable and photogenic onsen traditions.

Kamegawa itself is an old district with a long bathing history and a relaxed, residential character. Alongside the sand bath it has traditional public bathhouses and a scattering of shops and eateries, but it lacks the crowds of the hell-tour areas, giving it an easygoing, local feel. Its position on the JR Nippo Main Line, a short walk from Kamegawa Station, makes it one of the more convenient Beppu Hatto districts to reach by train rather than bus.

The seaside setting adds a dimension the inland onsen quarters lack. There are views across Beppu Bay, sea breezes to temper the geothermal heat, and a stretch of coast to stroll before or after bathing. In the cooler months the combination of hot sand and cool sea air is especially pleasant, and the black sand retains warmth well even on chilly days.

The sunayu experience is straightforward: you change into a provided cotton yukata, lie down in a shallow trough, and attendants shovel warm sand over you, leaving only your head exposed. Ten to fifteen minutes is usually plenty - the heat builds steadily - after which you rinse off and can soak in an adjoining hot-spring bath. It is accessible to most visitors, though anyone with heart conditions or who is pregnant should check first, as with any hot bath.

A visit of just over an hour covers the sand bath, a rinse-off soak and a short seaside walk. The district combines naturally with a broader loop of northern Beppu, and its train access makes it easy to slot in without a car.

As one of the eight Beppu Hatto districts, Kamegawa broadens the city's onsen repertoire beyond hot water and steam to include hot sand and sea air. It is proof of Beppu's inventiveness with its geothermal gifts: here the volcanic heat does not just fill baths but warms the very beach, letting visitors be gently cooked by the coast in a way found almost nowhere else in Japan.