By Eric Morrow
“A round man cannot be expected to fit into a square hole right away,” quipped Mark Twain. “He must have time to modify his shape.”
With this hint in mind, try to find how black modifies the shape of this week’s position so black can fit into a critical square and mate white in three moves.
The critical square in this week’s position is c1. Occupying that square with a queen or rook with the support of the a3 bishop or b2 pawn mates. But white blocks access to the c1 square and guards it with a rook.
Black breaks through first with queen takes rook, checking white. This forces white’s bishop to capture black’s queen, which clears a path to the c1 square for black’s c8 rook.
After black’s rook checks from c1, white’s rook takes black’s rook, only to be taken in turn by black’s pawn on b2. The pawn promotes to a queen or rook as it takes white’s rook on c1 while simultaneously mating white.
The lesson here is that in chess you can fit a round piece into a square hole.