18. The role of luck in chess (example)

{In 1989 I achieved my best ever performance in an open tournament by winning
the strong Biel Open. I was in good shape, but good luck also played a role.
If you want to win a strong tournament against strong competitors, you always
need both. I started the tournament with a personal record of 6/6. The
following game was the one of the 6th round. You can conclude, that my
opponent must also have played very well before, most probably having scored 4.5/5. But despite his good form, in this game, he allowed himself a series of
three bad moves in a row. It simply wasn't his day which I call good luck for
me.} 1. d4 Nf6 2. Nf3 e6 3. e3 c5 4. c4 d5 5. Nc3 Nc6 6. a3 {Diagram [#] That's another way of handling this position. As you know, Peter Wells played
6.cxd5 here.} a6 7. dxc5 Bxc5 8. b4 Bd6 {An alternative of equal strength is 8.
..Ba7.} 9. Bb2 O-O {Diagram [#]} 10. cxd5 {If White doesn't want to
precipitate an isolani-sructure, he could go for} (10. Qc2 {Note, that White
doesn't move his king's bishop, hoping that Black now complies with 10...dxc4,
so that the bishop could be developed to c4 in one move. But Black also has
good "waiting moves" at his disposal:} Qe7 11. Rd1 Rd8 {and now White has to
either change the pawn structure or finally to move his bishop.}) 10... exd5
11. Be2 Bg4 12. O-O {Diagram [#]} Bc7 $2 {My intention is clear. I wanted to
develop the queen to d6, with threats against his king, and the queen's rook
to d8 afterwards. Unfortunately, the move comes with two problems. At c7, the
bishop is exposed to the sequence b5 axb5 / Nxb5. Hence it would be better
placed at b8, after the preliminary Rc8. Secondly, I should have defended
against the plan Rc1, Na4-c5, which would have been accomplished by} (12... Rc8
13. Rc1 Re8 14. Re1 (14. Na4 Ne4) 14... Bb8 15. Na4 (15. h3 Bh5 16. b5 axb5 17.
Nxb5 Ne4 $11) 15... Ne4 (15... Qd6 $2 {Radjabov,T (2713)-Leko,P (2730) Beijing
2013}) 16. Nc5 (16. h3 Bxf3 17. Bxf3 Qd6 $11) 16... Bxf3 17. Bxf3 Bxh2+ 18. Kf1
(18. Kxh2 Qh4+ 19. Kg1 Qxf2+ 20. Kh1 Qxb2) 18... Be5 19. Bxe5 Nxe5 20. Bxe4
dxe4 21. Qxd8 Rexd8 22. Nxe4 $11) 13. b5 (13. Rc1 $5 Qd6 (13... Re8 14. Na4 Ne4
15. Nc5) 14. g3 $14 Rac8 (14... Rad8 15. Na4 (15. b5 Na5 16. Qc2 $14) 15... Ne4
16. Nd4 $36) (14... Rfe8 15. Na4 Ne4 16. Nc5 Nxc5 17. Rxc5 Rad8 18. Qd3 $36 {
[%cal Rf3g5]}) 15. Na4 (15. b5 Ne7 (15... Na5 16. bxa6 bxa6 17. Na2 {[%cal
Ra2b4,Rb2e5]}) 16. Qd3 Bf5 17. Qd4 $14) 15... Ne4 16. Nc5 Nxc5 17. Rxc5 Rfd8
18. Nd4 Bxe2 19. Qxe2 Bb6 20. Nxc6 Rxc6 21. Rxc6 Qxc6 22. Rc1 Qe6 23. Rd1 f6
24. Bd4 Bc7 25. Qd3 $14) 13... Na5 14. bxa6 bxa6 {Diagram [#]} 15. Na4 $2 {White should have
tried to transfer his knight to b4. The following sequence leaves him with the
better minor piece.} (15. Na2 {[%cal Ra2b4,Rb4d5,Rb4a6,Rb2f6]} Bxf3 16. Bxf3
Bxh2+ 17. Kxh2 Qb8+ 18. Kg1 Qxb2 19. Nb4 Nc4 20. Ra2 Qe5 21. Nxd5 Rac8 22.
Nxf6+ Qxf6 23. Be2 $14) 15... Re8 $11 16. h3 (16. Bxf6 Qxf6 17. Rc1 (17. Qxd5 $2
Rad8 18. Qc5 (18. Qa2 $2 Bxf3 19. Bxf3 Qh4 {[%cal Rh4h2,Rh4a4]}) 18... Nb3 19.
Qxc7 Nxa1) 17... Qd6 18. g3 Rac8 19. Qd3 Nc4 20. Nc3 Bxf3 21. Bxf3 Ne5 22. Qxd5
Qxa3 $11) (16. Rc1 Ne4 $11) 16... Bxf3 17. Bxf3 Qd6 18. g3 Nc4 19. Bd4 $2 {
Diagram [#] The first of three bad moves in a row. The initiative passes on to
me.} (19. Bg2 Nxb2 20. Nxb2 $11) 19... Nxe3 $1 20. Bxe3 $2 {It was not too
late for equality by sacrificing a pawn for a short time.} (20. Bc5 Qxc5 21.
Nxc5 Nxd1 22. Rfxd1 Red8 23. Rac1 {There is no apparent way to hang on to the
pawn. Black suffers from two weakness on d5 and a6 as well as a shaky bishop.}
Ra7 (23... Be5 24. a4 g6 25. Rb1 Kg7 26. Rb6 $11) 24. Nb3 Kf8 25. Nd4 Rb7 26.
Nc6 Rd6 27. Nb4 $11) 20... Rxe3 21. fxe3 $2 {This last mistake loses on the
spot. Of course, White still had some fighting chances:} (21. Bg2 Rxa3 22. Rxa3
Qxa3 23. Bxd5 Nxd5 (23... Rd8 24. Qb3) 24. Qxd5 Rd8 25. Qc6 Be5 26. Kg2 g6 $17
27. Qxa6 $2 Rd2 {[%cal Ra3g3]} 28. Qc8+ Kg7 29. Qg4 Qb3 $19 {[%csl Ya4]} 30.
Kg1 Bd4) 21... Qxg3+ 22. Bg2 Qh2+ 23. Kf2 Ne4+ {Diagram [#]} (23... Ne4+ 24.
Kf3 Qg3+ 25. Ke2 Qxg2+ 26. Kd3 Qg6 $19 (26... Rb8 $19)) 0-1