I recently saw a chess match being played. After a few moves, Black was to move, and the board was exactly as at the beginning, except that the white king rook (at h1) was missing. How did Black capture it -- specifically, what was the actual move?
(In reply to
Well.. by bob909)
More, formally, until the time of the rook capture, black has an odd number of rooks/knights on white squares after an odd number of moves and an even number of rooks/knights on white squares after an even number of moves. If the white rook was captured at h1, white has the property that after the time of the capture, it has an odd number of rooks/knights on white squares after an even number of moves and an even number of rooks/knights on white squares after an odd number of moves.
But since the ending configuration has one white knight/rook on a white square, this would mean that white moved an even number of times, and thus that black moved an odd number of times. And if black moved an odd number of times, it would have an odd number of rooks/knights on white squares, implying that it is not at its original configuration.
Thus the capture move is Nxg1.
re: Well..(a little more formally)
