Answers.Body: <h1>TL;DR</h1>
  <p>Stockfish 14+ NNUE (depth = 47, 4143k nodes/s) evaluates this position as <strong>+1.1</strong> due to 1. gxh5 and the follow-on perfect play (the 2nd best variation starting with 1. cxb7 evaluates at <strong>-1.7</strong>). See <a href="https://lichess.org/analysis/standard/2rq3r/1p3pk1/p1Pp2p1/P2Pp2n/1P4P1/5P2/6Pp/N1bRQB1K_w" rel="nofollow noreferrer">position on Lichess</a>.</p>
  <p>Engine evaluation suggests perfect play leads to a theoretical win for White (using 7 piece tablebases). There are multiple positions along the way where White has only 1 move to retain advantage where the 2nd best move loses (not draws).</p>
  <h1>The Game</h1>
  <pre><code>[Title &quot;Erenburg - Nakamura, Reykjavik (2004)&quot;]
  [FEN &quot;rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1&quot;]
  [startply &quot;54&quot;]
  
  1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. f3 e5
  7. Nb3 Be6 8. Be3 Nbd7 9. Qd2 h5 10. a4 Be7 11. Be2 g6 12. a5
  h4 13. O-O Kf8 14. Nd5 Bxd5 15. exd5 Rc8 16. c4 Kg7 17. Rac1
  Nh5 18. Rfd1 Nf4 19. Bf1 Bg5 20. Na1 Nf6 21. b4 N6h5 22. c5
  Ng3 23. c6 h3 24. hxg3 h2+ 25. Kh1 Nh5 26. Qe1 Bxe3 27. g4
  Bxc1 28. gxh5 Bb2 29. Nb3 b5 30. Qd2 Bd4 31. Nxd4 exd4
  32. hxg6 fxg6 33. Qxd4+ Kf7 34. Bd3 Re8 35. Be4 Qf6 36. Qb6
  Rb8 37. Qa7+ Qe7 38. Qe3 Qf6 39. Rc1 Re7 40. Qh6 Qg7 41. Qh3
  Rh8 42. Qg4 Qh6 43. Rc2 Qg7 44. Rc1 Qh6 45. Re1 g5 46. Rc1 Rc7
  47. Bf5 Qh4 48. Bd7 Qxg4 49. Bxg4 Ke7 50. Re1+ Kd8 51. Re6 Rf7
  52. Rxd6+ Kc7 53. Rg6 Rf4 54. Rg7+ Kd6 55. Rd7+ Ke5 56. c7 Rc4
  57. Bh3 Rh6 58. Kxh2 g4 59. fxg4 Rd6 60. Rf7 Kxd5 61. g5 Rdc6
  62. g6 1-0
  </code></pre>
  <h1>Analysis after 27...Bxc1</h1>
  <p>Using Stockfish's principal variation, after 8 moves Black controls the c-file while White's Bishop and Queen have open diagonals to the kingside. White has advanced the a-pawn to the 6th rank. Play proceeds with some exchanges and shuffling before heading to a QB+4 vs QB+2 ending with opposite colored Bishops and a dominant Black King.</p>
  <p>However, perfect play seemingly results in a Q+2 vs Q+1 endgame where White is theoretically winning (using 7 piece tablebases).</p>
  <pre><code>[Title &quot;Analysis - Position after 27...Bxc1&quot;]
  [FEN &quot;2rq3r/1p3pk1/p1Pp2p1/P2Pp2n/1P4P1/5P2/6Pp/N1bRQB1K w Q - 0 1&quot;]
  
  1. gxh5 {Stockfish 14+ NNUE (depth = 47, 4143k nodes/s) evaluates this position as +1.1} Bf4 2. cxb7 Rb8 3. hxg6 Rxb7 4. Bxa6 Rc7 5. Bd3 Qc8 6. Nb3 fxg6 7. a6 Rf8 8. Ra1 Rh8 {Continuing (depth = 38, 4404k nodes/s)} 9. Rd1 Rf8 10. Na5 Rc3 11. Qe4 Qf5 12. Qe2 Qf7 13. Qe1 Ra3 14. Nc4 Rxa6 15. Nxe5 Bxe5 16. Bxa6 Ra8 {Continuing (depth = 43, 4506k nodes/s)} 17. Bd3 Qf4 18. b5 Ra3 19. b6 Rb3 20. Rb1 Rxb1 21. Bxb1 Qd4 22. b7 Bg3 23. Qe7+ Kh6 24. Qf8+ Kg5 {Continuing (depth = 64, 7058k nodes/s). From here, top two moves are 25. f4++ or 25. Qe7+, both with favorable evaluations at +2.3.} 25. f4+ Bxf4 26. Qe7+ Kh6 27. Qe1 Qb6 28. b8=Q Qxb8 29. Qe4 Kg7 30. Qxg6+ Kf8 31. Qf6+ Kg8 32. Qxf4 Qxb1+ (25. Qe7+ Kh6 26. Qf8+ Kg5 27. f4+ Bxf4 28. Qe7+ Kh6 29. Qe1 Qb6 30. b8=Q Qxb8 31. Qe4 Kg7 32. Qxg6+ Kf8 33. Qf6+ Kg8 34. Qxf4 Qxb1+ 35. Kxh2 {And White wins based on the 7 piece tablebases.}) 33. Kxh2 {And White wins based on the 7 piece tablebases.}
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-11-19T21:39:27.810Z
Answers.LastActivityDate: 2021-11-20T02:54:23.633Z
Answers.LastEditDate: 2021-11-20T02:54:23.633Z
Answers.UserDisplayName: SecretAgentMan
Body: <p>Did Erenburg operated a winning exchange sacrifice vs Nakamura in the Reykjavik 2004 game , Sicilian Najdorf opening ? Or could Nakamura have defended the position ?</p>
  <p>I analyzed the following position with Houdini 6.02 but reached only depth = 34 after 40 minutes. The position is the following. White to move.</p>
  <pre><code>[FEN &quot;2rq3r/1p3pk1/p1Pp2p1/P2Pp2n/1P4P1/5P2/6Pp/N1bRQB1K w - - 0 1&quot;]
  [White &quot;Erenburg&quot;]
  [Black &quot;Nakamura&quot;]
  </code></pre>
  <p>Is this position a win for White or a draw?</p>
  
Tags: <analysis><nakamura>
Title: Erenburg vs Nakamura 2004
ThreadText: # Erenburg vs Nakamura 2004
  
  (Asked by: username_0 on 2021-11-19)
  
  Did Erenburg operated a winning exchange sacrifice vs Nakamura in the Reykjavik 2004 game , Sicilian Najdorf opening ? Or could Nakamura have defended the position ?
  I analyzed the following position with Houdini 6.02 but reached only depth = 34 after 40 minutes. The position is the following. White to move.
  [FEN "2rq3r/1p3pk1/p1Pp2p1/P2Pp2n/1P4P1/5P2/6Pp/N1bRQB1K w - - 0 1"]
  [White "Erenburg"]
  [Black "Nakamura"]
  
  Is this position a win for White or a draw?
  
  **Tags:** analysis, nakamura
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2021-11-19. Score: 3
  
  TL;DR
  Stockfish 14+ NNUE (depth = 47, 4143k nodes/s) evaluates this position as +1.1 due to 1. gxh5 and the follow-on perfect play (the 2nd best variation starting with 1. cxb7 evaluates at -1.7). See position on Lichess.
  Engine evaluation suggests perfect play leads to a theoretical win for White (using 7 piece tablebases). There are multiple positions along the way where White has only 1 move to retain advantage where the 2nd best move loses (not draws).
  The Game
  [Title "Erenburg - Nakamura, Reykjavik (2004)"]
  [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
  [startply "54"]
  
  1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. f3 e5
  7. Nb3 Be6 8. Be3 Nbd7 9. Qd2 h5 10. a4 Be7 11. Be2 g6 12. a5
  h4 13. O-O Kf8 14. Nd5 Bxd5 15. exd5 Rc8 16. c4 Kg7 17. Rac1
  Nh5 18. Rfd1 Nf4 19. Bf1 Bg5 20. Na1 Nf6 21. b4 N6h5 22. c5
  Ng3 23. c6 h3 24. hxg3 h2+ 25. Kh1 Nh5 26. Qe1 Bxe3 27. g4
  Bxc1 28. gxh5 Bb2 29. Nb3 b5 30. Qd2 Bd4 31. Nxd4 exd4
  32. hxg6 fxg6 33. Qxd4+ Kf7 34. Bd3 Re8 35. Be4 Qf6 36. Qb6
  Rb8 37. Qa7+ Qe7 38. Qe3 Qf6 39. Rc1 Re7 40. Qh6 Qg7 41. Qh3
  Rh8 42. Qg4 Qh6 43. Rc2 Qg7 44. Rc1 Qh6 45. Re1 g5 46. Rc1 Rc7
  47. Bf5 Qh4 48. Bd7 Qxg4 49. Bxg4 Ke7 50. Re1+ Kd8 51. Re6 Rf7
  52. Rxd6+ Kc7 53. Rg6 Rf4 54. Rg7+ Kd6 55. Rd7+ Ke5 56. c7 Rc4
  57. Bh3 Rh6 58. Kxh2 g4 59. fxg4 Rd6 60. Rf7 Kxd5 61. g5 Rdc6
  62. g6 1-0
  
  Analysis after 27...Bxc1
  Using Stockfish's principal variation, after 8 moves Black controls the c-file while White's Bishop and Queen have open diagonals to the kingside. White has advanced the a-pawn to the 6th rank. Play proceeds with some exchanges and shuffling before heading to a QB+4 vs QB+2 ending with opposite colored Bishops and a dominant Black King.
  However, perfect play seemingly results in a Q+2 vs Q+1 endgame where White is theoretically winning (using 7 piece tablebases).
  [Title "Analysis - Position after 27...Bxc1"]
  [FEN "2rq3r/1p3pk1/p1Pp2p1/P2Pp2n/1P4P1/5P2/6Pp/N1bRQB1K w Q - 0 1"]
  
  1. gxh5 {Stockfish 14+ NNUE (depth = 47, 4143k nodes/s) evaluates this position as +1.1} Bf4 2. cxb7 Rb8 3. hxg6 Rxb7 4. Bxa6 Rc7 5. Bd3 Qc8 6. Nb3 fxg6 7. a6 Rf8 8. Ra1 Rh8 {Continuing (depth = 38, 4404k nodes/s)} 9. Rd1 Rf8 10. Na5 Rc3 11. Qe4 Qf5 12. Qe2 Qf7 13. Qe1 Ra3 14. Nc4 Rxa6 15. Nxe5 Bxe5 16. Bxa6 Ra8 {Continuing (depth = 43, 4506k nodes/s)} 17. Bd3 Qf4 18. b5 Ra3 19. b6 Rb3 20. Rb1 Rxb1 21. Bxb1 Qd4 22. b7 Bg3 23. Qe7+ Kh6 24. Qf8+ Kg5 {Continuing (depth = 64, 7058k nodes/s). From here, top two moves are 25. f4++ or 25. Qe7+, both with favorable evaluations at +2.3.} 25. f4+ Bxf4 26. Qe7+ Kh6 27. Qe1 Qb6 28. b8=Q Qxb8 29. Qe4 Kg7 30. Qxg6+ Kf8 31. Qf6+ Kg8 32. Qxf4 Qxb1+ (25. Qe7+ Kh6 26. Qf8+ Kg5 27. f4+ Bxf4 28. Qe7+ Kh6 29. Qe1 Qb6 30. b8=Q Qxb8 31. Qe4 Kg7 32. Qxg6+ Kf8 33. Qf6+ Kg8 34. Qxf4 Qxb1+ 35. Kxh2 {And White wins based on the 7 piece tablebases.}) 33. Kxh2 {And White wins based on the 7 piece tablebases.}
  
  
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