Undefined

smullyan undefined chess puzzle

Another retrograde chess puzzle by Raymond Smullyan. The pawn on g3 is of unknown color. During the game no piece has moved from a light square to a dark one or vice versa. Is the unknown pawn black or white?

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The d2 and f2 pawns have not moved; how did the white king escape onto the board? White must have castled kingside. Now, if the pawn on g3 were white then it must have come from h2, and the king could not have left his castle. Therefore the pawn must be black.

May 16, 2010January 24, 2013 | Puzzles