It was strange to meet him halfway across Siberia, at a lonely town on the Amur river. He had already travelled overland some 2,600 miles from Moscow, whereas I had followed the nascent Amur on a wandering route out of Mongolia. He appeared a little studious, even when he was young, pale and lightly bearded, with an expression of faintly unreadable concern. How he was dressed I do not know: perhaps in the double-breasted overcoat of a later photograph, to protect his tubercular lungs from the evening chill.

Our itineraries collided at the little town of Sretensk. But I missed him by 128 years: Anton Chekhov, journeying to the island of Sakhalin in the Russian Pacific, whose penal colonies he would study for nearly three months. The Amur here is lushly beautiful. It is the tenth-longest river on earth, and for over a thousand miles it forms a nervous border with China. The forest descends its banks in curtains of birch and larch. As it moves southeastward, it swells to a sombre flood.

Here at Sretensk, travellers from European Russia embarked on ironclad steamers that would carry them east to the Pacific. It is a poor town now, quieter than when Chekhov arrived, and it was days before a small passenger boat took me on past the half-deserted villages downriver. In the