Originally posted by GargantuaThis one is a classic. If you have seen it before, don't spoil it.
[fen]rnbqkbnr/pp3ppp/2p1p3/8/4P3/8/PPPP1PPP/RNBQK1NR b KQkq - 0 1[/fen]
Like the previous puzzle this one could be solved by retroanalysis too, but unlike in the previous puzzle the following position could have been practically reached in a normal chess game. However I very much doubt it ever has. Here's the question: 4(!) moves have been played, can you tell me which ones? White to move now and what are the moves preceding this position?