[Event "?"] [Site "?"] [Round "0"] [White "Bronstein"] [Black "Boleslavsky"] [Result "1-0"] [ECO "D85"] [Opening "Gruenfeld: Exchange, 5.e4"] 1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 c5 7. Bc4 Bg7 8. Ne2 O-O 9. O-O cxd4 10. cxd4 Nc6 11. Be3 Bg4 12. f3 Na5 13. Bd3 Be6 {In this we ll known position the offer of the exchange by 14. Pd5 is very strong. The reason to be found in the following considerations: I) White gets the Bishop pair II) With the disappearance of the Bishop from g7, Black's ... Pg6 is only a weakening III) White pawn majority in the centre, and this always favours the attacker. Black's Queenside majority will have more significance in theendgame} 14. d5 $1 Bxa1 15. Qxa1 f6 {A further w eakening, which, however, is unavoidable, as White is threatening to regain the exchange with Bh6, leaving Black with no compensation for his weakened Kingside} 16. Bh6 Qb6+ ( 16... Re8 17. Nf4 (17. Bb5 $4 Qb6+) 17... Bf7) 17. Kh1 $1 { White values his positional advantages higher than the Exchange} (17. Nd4 Bd7 ( 17... -- 18. Rb1 Qc5 19. Rc1 Qa3 20. dxe6) 18. Rb1 Qc5 19. Rc1 Qb6 20. Bxf8 Rxf8 21. h4 Qd6) 17... Rfd8 { The only way to save the Exchange, but it doesn't improve Black's chances.} ( 17... Bf7) 18. Rb1 Qc5 $1 (18... Qf2 19. Qc3 Qh4 20. Bf4 $16) (18... Qd6 19. Qc3 b6 20. Bf4 Qd7 (20... Qc5 21. Qxc5 bxc5 22. Bc7) 21. Bb5 $18) (18... Qc7 19. Bf4 Qc8 20. Rc1) 19. Bd2 (19. Rb5 Qa3 20. Bc2 Bd7 (20... Rac8 $3 {Flohr} 21. Bc1 (21. Qb1 Bd7 22. Bc1 Qd6 23. Rxa5 Qc7) (21. Nd4 Rxc2 22. Nxc2 Qa4 23. Rxa5 (23. Qb2) (23. Nd4) 23... Qxa5 24. dxe6 Qxa2) 21... Qd6 22. Rxa5 Rxc2 23. dxe6 Qd1+ 24. Ng1 Qxg1+ 25. Kxg1 Rd1#) 21. Bc1 Qxc1+ 22. Qxc1 Bxb5 23. Nd4 Bd7 24. Qa3) 19... b6 20. Bb4 Qc7 21. Rc1 Qb7 (21... Qd7 22. Nd4 Bf7 23. Bb5 Qb7 24. Bxa5 bxa5 25. Bc6 $16) 22. Qb1 Rab8 (22... Bc8 23. Nf4 { rapidly winning attack}) 23. dxe6 {A rook is no match for two Bishops, especially when the position leaves something to be desired in other respects} 23... Nc6 24. Bc3 Ne5 25. Bb5 Rbc8 26. Bxe5 Rxc1+ 27. Qxc1 fxe5 28. Bd7 Qa6 29. Ng3 Qxa2 30. h4 Rf8 31. Qg5 Rf6 32. Qxf6 $1 1-0