Answers.Body: <p>I discovered a game from a few weeks ago that features a <strong>forced mate in 13 moves</strong> that was administered OTB. The game in question is <a href="https://www.chessgames.com/perl/chessgame?gid=1978667" rel="nofollow noreferrer">Dubov-Svane</a>, and the claim came from <a href="https://youtu.be/cocbOmTO3ac" rel="nofollow noreferrer">Agadmator’s analysis</a>, for which engine analysis yielded his claim correct.</p>
  <p>Although Black made a move to try and trick White in the real game, shortening the sequence, in my eyes, it still qualifies as a forced mate in 13 moves.</p>
  <p>What Black &quot;should&quot; have played, in terms of engine analysis that is, is included as a sideline.</p>
  <pre><code>[Title &quot;Daniil Dubov-Rasmus Svane. European Team Championship, Batumi Georgia, 10/31/19&quot;]
  [FEN &quot;&quot;]
  [startply &quot;58&quot;]
  
  1. c4 e6 2. Nc3 d5 3. d4 Nf6 4. Nf3 Be7 5. Bf4 O-O 6. e3 b6 7. Qc2 Ba6 8. O-O-O dxc4 9. Ng5 Nc6 10. a3 g6 11. h4 Bd6 12. g3 Qe7 13. h5 e5 14. hxg6 hxg6 15. Bg2 exf4 16. Bxc6 fxg3 17. Kb1 Rad8 18. f4 Bc8 19. Rde1 Kg7 20. Nd5 Nxd5 21. Rh7+ Kg8 22. Rxf7 Rxf7 23. Qxg6+ Kf8 24. Qh6+ Rg7 25. Bxd5 Ke8 26. Qh5+ Kd7 27. Qh3+ Ke8 28. Qh5+ Kd7 29. Be6+ Kc6 30. Qf3+ Kb5 31. Bxc4+ Ka5 32. Qd5+ Bc5 33. b4+ Ka4 34. Qg2 (34... Bf5+ 35. Ka2 Rd5 36. Qxd5 Qd7 37. Qb7 a5 38. Ne4 Bxd4 39. exd4 Bxe4 40. Qxe4 Qf5 41. Qxf5 axb4 42. Bb3#) Bxb4 35. Qc6+ Kxa3 36. Bb3 Bd7 37. Qc1+ Kxb3 38. Qc2+ Ka3 39. Qa2#
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-06-28T21:13:43.010Z
Answers.Text: 34 . . . Bxb4 is not necessarily a mistake: it forced White to find 36 Bb3! to win, while after Bf5+ 35 Ka2 Rd5 36 Qxd5 the win is routine even if it takes a few moves longer to reach checkmate.
Answers.UserDisplayName: Noam D. Elkies
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-11-28T01:32:15.550Z
Answers.LastActivityDate: 2022-06-28T22:26:05.617Z
Answers.LastEditDate: 2022-06-28T22:26:05.617Z
Answers.UserDisplayName: Rewan Demontay
Answers.Body: <p>Wikipedia's
  <a href="https://en.wikipedia.org/wiki/Bishop_and_knight_checkmate" rel="nofollow noreferrer">article</a>
  on the KBN/K checkmate cites a blindfold game(!) between grandmasters
  (L. Ljubojević and J. Polgár)[https://www.chessgames.com/perl/chessgame?gid=1092636] at 1994 Amber Chess Tournament.
  Polgár won by checkmate, and the last ten moves were played correctly
  by both players (the last &quot;error&quot; was 96...Ke4-e3, when Bd1-f3 would have
  mated a move faster according to the &quot;tablebase&quot;):</p>
  <pre><code>[Title &quot;L. Ljubojević vs. J. Polgár, 1994 Amber Chess Tournament (blindfold)&quot;]
  [FEN &quot;&quot;]
  [startply &quot;192&quot;]
  
  1. e4 c5 2. c3 d6 3. d4 Nf6 4. Bd3 g6 5. h3 Bg7 6. Nf3 O-O 7. O-O Qc7 8. Qe2 a6 9. Bf4 b5 10. e5 Nd5 11. Bg3 Qb6 12. Nbd2 cxd4 13. cxd4 Nb4 14. Be4 d5 15. Bb1 a5 16. Nb3 a4 17. Nc5 N8c6 18. Qe3 Na5 19. Bf4 Nc4 20. Qc3 Nc6 21. a3 f6 22. exf6 Rxf6 23. Bg5 Rf7 24. Be3 Rxf3 25. gxf3 e5 26. dxe5 Bxe5 27. Nd3 d4 28. Nxe5 N4xe5 29. Ba2+ Kg7 30. Bd5 Ra6 31. f4 Nc4 32. Bxc6 dxc3 33. Bxb6 Rxb6 34. Bxb5 Rxb5 35. bxc3 Bxh3 36. Rfd1 Rb3 37. Rd4 Rxc3 38. Rad1 Bf5 39. Re1 Nb2 40. Re3 Rxe3 41. fxe3 Be6 42. e4 Bb3 43. Rd7+ Kf6 44. Rxh7 Nc4 45. e5+ Ke6 46. Rg7 Bc2 47. Rc7 Nxa3 48. Rc3 Bb3 49. Rc6+ Kf7 50. Rc7+ Kf8 51. Rc6 Kg7 52. Rc7+ Kh6 53. Rc6 Kg7 54. Rc7+ Kf8 55. Rc6 Bf7 56. Ra6 Be8 57. Ra7 Nc2 58. Kf2 a3 59. Ke2 Nd4+ 60. Kd2 Nb5 61. Ra6 Ke7 62. e6 Nd6 63. Kc2 Nc4 64. Kc3 Bb5 65. Ra7+ Kxe6 66. Kb4 Nd6 67. Rxa3 Be8 68. Ra5 Nb5 69. Kc5 Kf5 70. Ra8 Nc7 71. Rc8 Ne6+ 72. Kd6 Ba4 73. Ra8 Bd1 74. Ra5+ Kf6 75. Ra1 Be2 76. Ra4 Bd1 77. Re4 Ng7 78. Re1 Bf3 79. Rf1 Be4 80. Re1 Kf5 81. Ke7 Nh5 82. Rg1 Nxf4 83. Rxg6 Nxg6+ 84. Kd6 Kf6 85. Kc5 Ke5 86. Kc4 Bd5+ 87. Kd3 Nf4+ 88. Ke3 Be4 89. Kd2 Kd4 90. Kc1 Kc3 91. Kd1 Bc2+ 92. Ke1 Kd3 93. Kf2 Ke4 94. Kg3 Bd1 95. Kf2 Nd3+ 96. Kg3 Ke3 97. Kh4 Kf4 98. Kh3 Ne1 99. Kh4 Ng2+ 100. Kh3 Kf3 101. Kh2 Kf2 102. Kh3 Be2 103. Kh2 Bg4 104. Kh1 Ne3 105. Kh2 Nf1+ 106. Kh1 Bf3#
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-06-29T04:33:14.757Z
Answers.LastActivityDate: 2022-07-09T23:59:19.277Z
Answers.LastEditDate: 2022-07-09T23:59:19.277Z
Answers.UserDisplayName: Noam D. Elkies
Body: <p>There are tons of questions about the longest forced mate on here and other chess forums. Usually the answers are the 2 Knights forced mate and another one that evidently takes 549 optimal moves. Ultimately those discussions often devolve into debate about the 50 move rule.</p>
  
  <p>However as a novice player it often boggles my mind when, in real games, players are able to recognize unavoidable checkmate on a non-empty board dozens of moves in advance. Hence, what I am wondering about is: what is the longest forced mate optimally played in documented competition? In other words, in competitive play (international, national, league, etc.), what comes to mind as the furthest time (in moves) from checkmate when resistance is futile? Something a la "that's mate in 15."</p>
  
  <p>Edit: I imagine that this situation usually brings about resignation, so I should clarify that I'm not interested in if it was ever played out, but rather what the maximum number of moves was in advance of checkmate when this futility was ensured.</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2018-01-20T22:21:09.027Z
Comments.Text: People resign when the position is "lost", but that doesn't mean there is a forced checkmate. It could just mean they are down enough material. I guess you could say mate is "unavoidable in dozens of moves" when you are down a piece, but that doesn't mean anyone can calculate how! The notion that anyone, even grandmasters, calculates dozens of moves in advance is a myth.
  
  Also, if you find a position from a real game that can be proven to be, say, mate in 20, that doesn't mean that either of the players noticed.
Comments.UserDisplayName: itub
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2018-01-21T05:18:56.830Z
Comments.Text: @itub: Interesting point; I hadn't realized that. The top players must at the least have profound recall of many permutations of moves given a number of scenarios. Perhaps it's just having played and studied so many games, almost any position is recognizable.
Comments.UserDisplayName: marcman
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2018-01-24T07:00:25.383Z
Comments.Text: It is not that almost any position is recognized but that it likely falls into a recognizable category.
Comments.UserDisplayName: DanielWainfleet
Tags: <checkmate><records><famous-games><forced-move>
Title: What is the longest forced mate optimally played in documented competition?
ThreadText: # What is the longest forced mate optimally played in documented competition?
  
  (Asked by: username_0 on 2018-01-20)
  
  There are tons of questions about the longest forced mate on here and other chess forums. Usually the answers are the 2 Knights forced mate and another one that evidently takes 549 optimal moves. Ultimately those discussions often devolve into debate about the 50 move rule.
  
  However as a novice player it often boggles my mind when, in real games, players are able to recognize unavoidable checkmate on a non-empty board dozens of moves in advance. Hence, what I am wondering about is: what is the longest forced mate optimally played in documented competition? In other words, in competitive play (international, national, league, etc.), what comes to mind as the furthest time (in moves) from checkmate when resistance is futile? Something a la "that's mate in 15."
  
  Edit: I imagine that this situation usually brings about resignation, so I should clarify that I'm not interested in if it was ever played out, but rather what the maximum number of moves was in advance of checkmate when this futility was ensured.
  
  **Tags:** checkmate, records, famous-games, forced-move
  
  > **Comments:**
  > **username_1**: People resign when the position is "lost", but that doesn't mean there is a forced checkmate. It could just mean they are down enough material. I guess you could say mate is "unavoidable in dozens of moves" when you are down a piece, but that doesn't mean anyone can calculate how! The notion that anyone, even grandmasters, calculates dozens of moves in advance is a myth.  Also, if you find a position from a real game that can be proven to be, say, mate in 20, that doesn't mean that either of the players noticed.  
  > **username_0**: @username_1: Interesting point; I hadn't realized that. The top players must at the least have profound recall of many permutations of moves given a number of scenarios. Perhaps it's just having played and studied so many games, almost any position is recognizable.  
  > **username_2**: It is not that almost any position is recognized but that it likely falls into a recognizable category.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_3 on 2019-11-28. Score: 11
  
  I discovered a game from a few weeks ago that features a **forced mate in 13 moves** that was administered OTB. The game in question is [Dubov-Svane](https://www.chessgames.com/perl/chessgame?gid=1978667), and the claim came from [Agadmator’s analysis](https://youtu.be/cocbOmTO3ac), for which engine analysis yielded his claim correct.
  
  Although Black made a move to try and trick White in the real game, shortening the sequence, in my eyes, it still qualifies as a forced mate in 13 moves.
  
  What Black "should" have played, in terms of engine analysis that is, is included as a sideline.
  
  ```
  [Title "Daniil Dubov-Rasmus Svane. European Team Championship, Batumi Georgia, 10/31/19"]
  [FEN ""]
  [startply "58"]
  
  1. c4 e6 2. Nc3 d5 3. d4 Nf6 4. Nf3 Be7 5. Bf4 O-O 6. e3 b6 7. Qc2 Ba6 8. O-O-O dxc4 9. Ng5 Nc6 10. a3 g6 11. h4 Bd6 12. g3 Qe7 13. h5 e5 14. hxg6 hxg6 15. Bg2 exf4 16. Bxc6 fxg3 17. Kb1 Rad8 18. f4 Bc8 19. Rde1 Kg7 20. Nd5 Nxd5 21. Rh7+ Kg8 22. Rxf7 Rxf7 23. Qxg6+ Kf8 24. Qh6+ Rg7 25. Bxd5 Ke8 26. Qh5+ Kd7 27. Qh3+ Ke8 28. Qh5+ Kd7 29. Be6+ Kc6 30. Qf3+ Kb5 31. Bxc4+ Ka5 32. Qd5+ Bc5 33. b4+ Ka4 34. Qg2 (34... Bf5+ 35. Ka2 Rd5 36. Qxd5 Qd7 37. Qb7 a5 38. Ne4 Bxd4 39. exd4 Bxe4 40. Qxe4 Qf5 41. Qxf5 axb4 42. Bb3#) Bxb4 35. Qc6+ Kxa3 36. Bb3 Bd7 37. Qc1+ Kxb3 38. Qc2+ Ka3 39. Qa2#
  
  ```
  
  > **Comments:**
  > **username_4**: 34 . . . Bxb4 is not necessarily a mistake: it forced White to find 36 Bb3! to win, while after Bf5+ 35 Ka2 Rd5 36 Qxd5 the win is routine even if it takes a few moves longer to reach checkmate.  
  
  ---
  
  ### Answer by username_4 on 2022-06-29. Score: 4
  
  Wikipedia's
  [article](https://en.wikipedia.org/wiki/Bishop_and_knight_checkmate)
  on the KBN/K checkmate cites a blindfold game(!) between grandmasters
  (L. Ljubojević and J. Polgár)[https://www.chessgames.com/perl/chessgame?gid=1092636] at 1994 Amber Chess Tournament.
  Polgár won by checkmate, and the last ten moves were played correctly
  by both players (the last "error" was 96...Ke4-e3, when Bd1-f3 would have
  mated a move faster according to the "tablebase"):
  
  ```
  [Title "L. Ljubojević vs. J. Polgár, 1994 Amber Chess Tournament (blindfold)"]
  [FEN ""]
  [startply "192"]
  
  1. e4 c5 2. c3 d6 3. d4 Nf6 4. Bd3 g6 5. h3 Bg7 6. Nf3 O-O 7. O-O Qc7 8. Qe2 a6 9. Bf4 b5 10. e5 Nd5 11. Bg3 Qb6 12. Nbd2 cxd4 13. cxd4 Nb4 14. Be4 d5 15. Bb1 a5 16. Nb3 a4 17. Nc5 N8c6 18. Qe3 Na5 19. Bf4 Nc4 20. Qc3 Nc6 21. a3 f6 22. exf6 Rxf6 23. Bg5 Rf7 24. Be3 Rxf3 25. gxf3 e5 26. dxe5 Bxe5 27. Nd3 d4 28. Nxe5 N4xe5 29. Ba2+ Kg7 30. Bd5 Ra6 31. f4 Nc4 32. Bxc6 dxc3 33. Bxb6 Rxb6 34. Bxb5 Rxb5 35. bxc3 Bxh3 36. Rfd1 Rb3 37. Rd4 Rxc3 38. Rad1 Bf5 39. Re1 Nb2 40. Re3 Rxe3 41. fxe3 Be6 42. e4 Bb3 43. Rd7+ Kf6 44. Rxh7 Nc4 45. e5+ Ke6 46. Rg7 Bc2 47. Rc7 Nxa3 48. Rc3 Bb3 49. Rc6+ Kf7 50. Rc7+ Kf8 51. Rc6 Kg7 52. Rc7+ Kh6 53. Rc6 Kg7 54. Rc7+ Kf8 55. Rc6 Bf7 56. Ra6 Be8 57. Ra7 Nc2 58. Kf2 a3 59. Ke2 Nd4+ 60. Kd2 Nb5 61. Ra6 Ke7 62. e6 Nd6 63. Kc2 Nc4 64. Kc3 Bb5 65. Ra7+ Kxe6 66. Kb4 Nd6 67. Rxa3 Be8 68. Ra5 Nb5 69. Kc5 Kf5 70. Ra8 Nc7 71. Rc8 Ne6+ 72. Kd6 Ba4 73. Ra8 Bd1 74. Ra5+ Kf6 75. Ra1 Be2 76. Ra4 Bd1 77. Re4 Ng7 78. Re1 Bf3 79. Rf1 Be4 80. Re1 Kf5 81. Ke7 Nh5 82. Rg1 Nxf4 83. Rxg6 Nxg6+ 84. Kd6 Kf6 85. Kc5 Ke5 86. Kc4 Bd5+ 87. Kd3 Nf4+ 88. Ke3 Be4 89. Kd2 Kd4 90. Kc1 Kc3 91. Kd1 Bc2+ 92. Ke1 Kd3 93. Kf2 Ke4 94. Kg3 Bd1 95. Kf2 Nd3+ 96. Kg3 Ke3 97. Kh4 Kf4 98. Kh3 Ne1 99. Kh4 Ng2+ 100. Kh3 Kf3 101. Kh2 Kf2 102. Kh3 Be2 103. Kh2 Bg4 104. Kh1 Ne3 105. Kh2 Nf1+ 106. Kh1 Bf3#
  
  ```
  
  
  ---
  
  