[Event "Leeds 1990"]  [White "John Nunn"]  [Black "Glenn Flear"]  [Result "1-0"]  [ECO "C80"]  [Annotator "ATH"]  [PlyCount "55"]  [EventDate "1990.??.??"]  [SourceTitle "StarBase 4.56"]  [SourceDate "2004.11.04"]  [SourceVersion "1"]  [SourceVersionDate "2004.11.04"]  [SourceQuality "2"]   1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Nxe4 6. d4 b5 7. Bb3 d5 8. dxe5  Be6 9. Nbd2 Nc5 10. c3 d4 11. Bxe6 ({Karpov introduced the amazing piece sac}  11. Ng5 {against Korchnoi in 1978 but it's been analyzed out} Qxg5 ({Korchnoi  declined with} 11... dxc3 12. Nxe6 fxe6 13. bxc3 Qd3 {and was lucky to escape  with a draw. Interestingly, in the 1989 Batsford Chess Openings II, Kasparov  gave} 14. Bc2 $6 Qxc3 15. Rb1 O-O-O $15 {but in his 1995 match against Anand,  14. Bc2 got an exclam (in his Informant notes) and he uncorked 15. Nb3!!}) 12.  Qf3 O-O-O 13. Bxe6+ fxe6 14. Qxc6 Qxe5 15. b4 Qd5 $1 16. Qxd5 exd5 17. bxc5  dxc3 18. Nb3 d4 19. Ba3 $11) 11... Nxe6 12. cxd4 Ncxd4 13. a4 (13. Ne4 {  is the old main line, e.g.,} Be7 (13... Qd5 $5) 14. Be3 Nf5 15. Qc2 O-O 16.  Neg5 $11 {Karpov-Korchnoi, 16th match game, 1981}) 13... Rb8 ({Stockfish gives  } 13... Nc6 {as best, e.g.,} 14. Qe2 Be7 15. Qe4 Nb4 16. axb5 O-O 17. bxa6 Rxa6  18. Rxa6 Nxa6 19. Nc4 $14) (13... Bc5 14. Ne4 Bb6 15. Nfg5 Qd5 {has been  played many times but Stockfish's} 16. a5 $1 $14 {does not appear to be in the  database}) (13... Be7 14. Nxd4 Nxd4 15. Ne4 Ne6 16. Be3 O-O 17. f4 $16 {  gave Karpov a crushing win and the world championship in the 18th and final  game of his 1981 match against Korchnoi}) 14. axb5 axb5 15. Nxd4 (15. Ne4 $1  $14) 15... Nxd4 $2 (15... Qxd4 $11) 16. Ne4 ({Even stronger, according to  Stockfish, is} 16. Nb3 Nxb3 17. Qxb3 Qc8 18. Rd1 Qe6 19. Qxe6+ fxe6 20. Ra6 $16  ) 16... Be7 $6 (16... Qd5) 17. Be3 Nc6 $2 (17... Ne6 18. f4 $16) 18. Qg4 $18 g6  $2 (18... Qd5 19. Ra6 $18 (19. Qxg7 Qxe5 $16)) 19. Bh6 Nxe5 20. Qf4 Nd3 (20...  f6 {is a whole pawn equivalent better but what's the difference between being  up the equivalent of six pawns and being up the equivalent of seven pawns?})  21. Qe3 f5 22. Rad1 ({Again, not that it matters but} 22. Rfd1 {is a whole  pawn equivalent better}) 22... fxe4 23. Qxe4 Kd7 {In an apparent attempt to  end his misery quickly, the Black king walks the plank rather than endure} (  23... Rb6 24. Rxd3 Rd6 25. Rfd1 {etc.}) 24. Rxd3+ Bd6 25. Qg4+ (25. Rxd6+ {  leads to mate in 12 (don't you hate computers?)}) 25... Kc6 26. Rc1+ Kb7 27.  Qe4+ Kc8 28. Qe6+ 1-0