Mount Asahidake, the highest point of this wild island, rose up before me in a great mass of black ash and eternal snow. The volcano hasn’t erupted for 200 years but the smell of sulphur still stings the nose. I stood on the edge of Sugatami Pond, one of many lucid pools that mark this marshland, and watched as the fog thickened around the slopes. The water at my feet was like glass, without crease or wrinkle despite the rain, almost mythical . . .