You lie down on the beach in a yukata. The attendant begins to cover you with sand — dark volcanic sand, naturally heated by the geothermal activity beneath Ibusuki's coast. The weight settles over your body. The heat penetrates from all directions at once. This lasts about fifteen minutes, and afterward you enter the regular hot spring bath. The sand bath at Ibusuki is not complicated. What is complicated is explaining why it is memorable in a way that other experiences are not. Part of the answer is passivity: you do nothing. You are simply there, held down by sand, warm in a way that is different from the warmth of water. The volcanic heat that produces this comes from the same geological forces that created Kagoshima Bay and the nearby active volcano of Sakurajima. Ibusuki is at the southern tip of the Satsuma Peninsula, a scenic drive from Kagoshima City. It is worth a full day rather than an afternoon. The sand bath is the reason to come; the town and its surroundings are the reason to stay. There is nothing quite like this anywhere else, which is its own kind of complexity.