“How the blazes do I know? I was only three, wasn’t I? I can’t remember.”

“You have been told. It was stuck in a mudbank. In your infant re-enactment you covered yourself in mud in a garden pond, don’t you remember?”

That was the kind of thing I had to know, and when I protested that no one was ever likely to ask me what games I had played when I was little, they wouldn’t argue, but would pass patiently on—to remind me of the fever I had had when I was fourteen, or the time I broke my arm falling from an apple tree.

All our talk was conducted in German, at which I made capital progress—indeed, Rudi’s one fear was that I might be too proficient, for Carl Gustaf apparently didn’t speak it too well, for all his Heidelberg education. Bersonin, who despite his taciturnity was a patient teacher, instructed me in Danish, but possibly because he himself only spoke it at second hand, I didn’t take to it easily. I never learned to think in it, which is unusual for me, and I found it ugly and dull, with its long vowels that make you sound as though you had wind.

But the real curse of my days was being instructed in the actual impersonation. We had the tremendous advantage, as I was to see for myself later, that Carl Gustaf and I were real doppelgängers, as like as two tits. Even our voices were the same, but he had mannerisms and tricks of speech that I had to learn, and the only way was for me to try attitudes and phrases over and over, in different styles, until Rudi would snap his fingers and exclaim: “Er ist es selbst! Now say it again, and yet again.”

For example, it seemed that if you asked Carl Gustaf a question to which the normal answer would have been “yes” or “of course”, he, instead of contenting himself with “ja”, would often say “sicher”, which means “positively, certainly”, and he would say it with a jaunty air, and a little stab of his right forefinger. Again, in listening to people, he would look past them, giving tiny occasional nods of his head and making almost inaudible grunts of agreement. Lots of people do this, but I don’t happen to be one of them, so I had to practise until I found myself doing it almost without thinking.

And he had a quick, brisk laugh, showing his teeth—I worked at that until my throat smarted and my jaws ached. But this was easy compared with the contortions I went through in trying to mimic his trick of raising one eyebrow by itself; I came near to setting up a permanent twitch in one cheek, and eventually they decided to let it be, and hope that no one noticed that my eyebrows perversely worked together.