1. d4 Nf6 2. c4 e6 3. g3 Bb4+ 4. Nd2 c5 5. a3 Bxd2+ 6. Qxd2 cxd4 7. Nf3 b6 8. Bg2 Bb7 9. Qxd4 Nc6 10. Qh4 d5 11. cxd5 Nxd5 12. Qxd8+ Rxd8 13. O-O Na5 14. Nd2 Ne7 15. b4 Bxg2 16. Kxg2 Nb7 17. Nb3 f6 18. Bd2 Kf7 19. Rfc1 Rd7 20. a4 e5 21. b5 Rc8 22. Rxc8 Nxc8 23. Rc1 Ne7 24. Bb4 Nd5 25. Ba3 Rc7 26. Rxc7+ Nxc7 27. e4 a6 28. bxa6 Nxa6 29. Kf3 Ke6 30. Ke3 h5 31. h3 g6 32. Kd3 Nc7 33. Kc4 f5 34. f3 fxe4 35. fxe4 Nd6+ 36. Kd3 Nf7 37. Bc1 Kd7 38. Be3 Kc6 39. Nd2 Ne6 40. Nb3 Nd6 41. h4 Nb7 42. Kc4 Nf8 43. Bh6 Nd7 44. Be3 Nf6 45. Kd3 Nd6 46. Nd2 Ng4 47. Bg1 Kb7 48. Nb3 Ka6 49. Nd2 Ka5 50. Kc3

50. Nc4+ Nxc4 51. Kxc4 Nf6 52. Be3! ( not 52. Kd3? Nd7 53. Kc4 Kxa4 54. Kd5 b5 and White cannot stop the pawn ) draws easily, e.g. 52... Nxe4 (52... Nd7?? 53. Kd5 and White is actually winning ) 53. Kd5 Nxg3 54. Kxe5 Nf5 55. Bg5 and Black will have to give up the knight for White's last pawn.

50... Nf6 51. Kd3 Nd7 52. Nf3 Kb4 53. Bxb6 Nxb6 54. Nxe5 Nxa4 55. Nxg6 Nc5+ 56. Ke3 Ncxe4 57. Nf4 Nxg3 58. Kf3 Ndf5 59. Nxh5?

59. Nd5+ Kc5 60. Nf6 followed by Kf4-g5 and Nxh5 draws.

59... Nxh5

The Nalimov tablebases show that this would be winning for Black if not for the 50-move rule; Black wins in 81 moves witn best play.

60. Kg4 Nfg3 61. Kf3 Kc4 62. Kg4 Kd4 63. Kg5 Ke5 64. Kg4 Ke4 65. Kg5 Kf3 66. Kg6 Kf4 67. Kf7 Kf5 68. Ke7 Ne4 69. Kd7 Ke5 70. Kc6 Kd4 71. Kb5 Kd5 72. Kb4 Nd6 73. Kc3 Ke4 74. Kb3 Kd3 75. Kb4 Kd4 76. Kb3 Ne4 77. Kb4 Nc3 78. Kb3 Nd5 79. Kc2?

This shortens the path to mate with best play significantly: Black now wins in 39 moves, ignoring the 50-move rule. This would be 58 moves after the last capture, so the critical point has not yet been reached. Instead 79. Kb2 loses in 67 moves with best play. The difference is very far from obvious.

79... Kc4 80. Kd2 Ndf6 81. Kc2 Ne4 82. Kb2 Nc5 83. Kc2 Nb3 84. Kb2 Nd4 85. Ka3 Kb5 86. Ka2 Ka4 87. Kb2 Kb4 88. Ka2?

White shortens the path to mate by 12 more moves; Black now wins in 13 moves with best play, or 41 moves after the last capture. Instead 88. Kc1! allows Black to win in 25 moves with best play, or 53 moves after the last capture. Black carries out the rest flawlessly.

88... Nc2 89. Kb2 Ne3 90. Ka2 Nc4 91. Kb1 Kc3 92. Kc1 Nb2 93. Kb1 Nd3 94. Ka2 Kb4 95. Ka1 Kb3 96. Kb1 Nhf4 97. h5 Nd5 98. h6 Nc3+ 99. Ka1 Nb4 100. h7 Nc2#

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Annotator(s): Tarun Kanyamarala, Alex Baburin's Endgame Play at Irish Championship 2023, ICTL (Irish Chess Technology Limited) web site, August 18, 2023 (not shown here).

Source(s): Lichess (https://lichess.org/study/3gPrmzSf/gGAbCWUh).

Event information: Tournament report.

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