There is no defence against the transfer of the bishop to f2. White resigned.
Unity Chess Club
Robert Byrne Robert Fischer New York ch-USA 1963 Black to move
White has incautiously moved his rook from f1, where it defended the f2-pawn, and put his dark-squared bishop on a3, where it looks active but does not control any central squares. Black brilliantly exploits these circumstances:
Byrne resigned: 22.Qf2 Qh3+ 23.Kg1 Re1+! (a small tactic to finish things off) 24.Rxe1 Bxd4 25.Qxd4 Qg2#.
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Mladen Muse 2470 Vigen Mirumian 2505 Berlin 1999 Black to move
The black pieces are directed at the kingside, which is defended only by White’s queen, which in her turn also defends the Ba4. If Black plays some sort of attacking move on the kingside, White will give an intermediate check with the bishop from b3, freeing his queen. Consequently, there followed instead the deflection motif:
The white king is all alone, and his other pieces are unable to come to his aid.
Unity Chess Club
Maxim Matlakov 2682 Pavel Eljanov 2729 St Petersburg 2013 Black to move
The white rooks have not yet taken up the open files, whilst his other pieces are on the queenside, far from his king. These factors gave Black the idea of landing a blow: