1. Nf3 d5 2. d4 Nf6 3. c4 c6 4. Nc3 dxc4 5. a4 White seeks to hold Black back from expanding on the queen's wing, and possibly to prevent Black from protecting the doubled pawn on c5, though that is not possible after ... a6. However, a more interesting plan might have been
5. e4 b5 6. Be2 b4 7. e5 bxc3 8. exf6 cxb2 9. Bxb2 (Also playable and endlessly fascinating is 9. fxg7 bxa1=Q 10. gxh8=Q Qa5+ 11. Kf1 This position is actually even, and White threatens Bh6 followed by Ne5, which looks very strong, but would you have the courage to play something so complicated against a master?)
9... exf6 10. Kf1 Be6 11. Qc2 and White has an impressive lead in development while Black cannot hold the pawn on c4.
5... Bf5 6. e3 e6 7. Bxc4 Bb4 8. O-O Nbd7 9. Bd2 9. Nh4 is worth consideration too.
9... a5 10. Re1 Nb6 11. Bf1 The bishop looked so good on the diagonal hitting f7 that 11. Bb3 seems the better move, but it is also needed on the kingside, and Be2 immediately might be chosen. Selecting between those alternatives is largely a matter of taste, since there are no immediate prospects of an attack. But the bishop is misplaced on f1.
11... Bg4 12. h3 Bh5 13. Be2 Just as good is 13. Nb1 looking for a restructuring of the entire White defense.
13... Nbd7 14. Rc1 O-O 15. Ne5? This is a strategic mistake, as it produces permanent structural weakness in the White pawns, being doubled on the e file and backwards on the b file.
Better was 15. Qc2 to prepare for the push of the e pawn.
15... Bxe2 16. Nxe2? This is a tactical mistake, as it puts the queen on the undefended d2 square which effectively pins the pawn on d4. It was necessary to recapture on e2 with the queen or rook to avoid the inevitable hardships which follow.
16... Bxd2 17. Nxd7 17. Qxd2 was not possible because 17... Nxe5 drops a piece to Black
17... Bxe1 18. Nxf8 The sequence white chose loses a knight for a pawn but leaves Black's pawn structure weakened. Slightly better would have been losing the exchange of knight for rook, as in 18. Nxf6+ Qxf6 19. Qxe1 But both lines leave White at a serious disadvantage.
18... Bb4 19. Nxe6 fxe6 20. Nf4 Qd6 21. g4 Rd8 21... Nd5 looks more natural.
22. Nd3 Nd7 Black can preserve the bishop to participate in a later queenside attack by simple moving the queen out of the way with 22... Qd5
23. Qb3 Qd5 24. Qc2 Qf3 25. Qc4 Nf8 26. Nf4 Re8 27. d5? White's game is beyond salvage at this point, but there is nothing to be gained from the move played.
27... exd5 28. Qd4 and White resigns without waiting for Black's next move.
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