Answers.Body: <p>The longest, <strong>trivial</strong> (trivial in terms of this question that is) known forced wins where White has just a knight or a bishop are 48 moves and 38 moves,  respectively. These records can be seen in Grigory Popov’s Russain <a href="http://superproblem.ru/archive/S_record-N.html" rel="nofollow noreferrer">&quot;Chess Book Of Records&quot;</a> on superproblem.ru.</p>
  <pre><code>[Title &quot;Patrick O’Shea, The Problemist 1989, 1st Prize, Mate In 48&quot;]
  [FEN &quot;8/p2N4/p7/p7/p7/K5pp/1p3npk/6bn w - - 0 1&quot;]
  
  1. Ne5 b1=N+ 2. Ka2 Nd2 3. Ka1 Nb3+ 4. Kb1 Nd2+ 5. Ka2 a3 6. Ka1 Nb3+ 7. Kb1 a2+ 8. Kxa2 Nd2 9. Ka1 Nb3+ 10. Kb1 Nd2+ 11. Ka2 a4 12. Ka1 Nb3+ 13. Kb1 Nd2+ 14. Ka2 a3 15. Ka1 Nb3+ 16. Kb1 a2+ 17. Kxa2 Nd2 18. Ka1 Nb3+ 19. Kb1 Nd2+ 20. Ka2 a5 21. Ka1 Nb3+ 22. Kb1 Nd2+ 23. Ka2 a4 24. Ka1 Nb3+ 25. Kb1 Nd2+ 26. Ka2 a3 27. Ka1 Nb3+ 28. Kb1 a2+ 29. Kxa2 Nd2 30. Ka1 Nb3+ 31. Kb1 Nd2+ 32. Ka2 a6 33. Ka1 Nb3+ 34. Kb1 Nd2+ 35. Ka2 a5 36. Ka1 Nb3+ 37. Kb1 Nd2+ 38. Ka2 a4 39. Ka1 Nb3+ 40. Kb1 Nd2+ 41. Ka2 a3 42. Ka1 Nb3+ 43. Kb1 a2+ 44. Kxa2 Nd2 45. Ka1 Nb3+ 46. Kb1 Nd2+ 47. Ka2 Nb1 48. Nf3#
  </code></pre>
  <hr />
  <pre><code>[Title &quot;ChristopherJeremy Morse, The Problemist 1978, Mate In 38&quot;]
  [FEN &quot;8/2p2p2/5p2/1B3p2/5p2/p2n4/kp1K1p2/b4r2 w - - 0 1&quot;]
  
  1. Bc4+ Kb1 2. Bxd3+ Ka2 3. Bc4+ Kb1 4. Bxf1 Ka2 5. Bc4+ Kb1 6. Kd1 f3 7. Kd2 f4 8. Kd1 f5 9. Kd2 f6 10. Kd1 c6 11. Kd2 c5 12. Kd1 f1=Q+ 13. Bxf1 Ka2 14. Bc4+ Kb1 15. Kd2 f2 16. Kd1 f3 17. Kd2 f4 18. Kd1 f5 19. Kd2 f1=Q 20. Bxf1 Ka2 21. Bc4+ Kb1 22. Kd1 f2 23. Kd2 f3 24. Kd1 f4 25. Kd2 f1=Q 26. Bxf1 Ka2 27. Bc4+ Kb1 28. Kd1 f2 29. Kd2 f3 30. Kd1 f1=Q+ 31. Bxf1 Ka2 32. Bc4+ Kb1 33. Kd2 f2 34. Kd1 f1=Q+ 35. Bxf1 Ka2 36. Bc4+ Kb1 37. Kd2 a2 38. Bd3#
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-10-12T15:37:54.787Z
Answers.LastActivityDate: 2021-05-02T21:20:39.287Z
Answers.LastEditDate: 2021-05-02T21:20:39.287Z
Answers.UserDisplayName: Rewan Demontay
Answers.Body: <p>According to <a href="http://kirill-kryukov.com/chess/longest-checkmates/longest-checkmates.shtml" rel="noreferrer">this website</a>, the longest checkmate for K+B vs. K+P is a simple mate in one, e.g.</p>
  
  <pre><code>[FEN "8/8/8/8/8/8/p7/k1K1B3 w - - 0 1"]
  </code></pre>
  
  <p>The K+N vs. K+P case is slightly more interesting, the following position is mate in seven:</p>
  
  <pre><code>[FEN "8/8/8/8/p7/8/N7/k1K5 w - - 0 1"]
  
  1. Nb4 a3 2. Nc2+ Ka2 3. Nd4 Ka1 4. Kc2 Ka2 5. Ne2 Ka1 6. Nc1 a2 7. Nb3#
  </code></pre>
  
  <p>You can play these endgames with online tablebases, e.g. <a href="http://www.shredderchess.com/online-chess/online-databases/endgame-database.html" rel="noreferrer">this one</a> from Shredder.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2018-01-24T22:23:05.067Z
Answers.Text: Oh, now that's a helpful website. Looking at the 5-man ones, there appears to be one that isn't just a forced simplification to the above two positions: KB vs KNP. Neat.
Answers.UserDisplayName: eyeballfrog
Answers.ContentLicense: CC BY-SA 3.0
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Answers.LastActivityDate: 2018-01-24T20:56:46.417Z
Answers.UserDisplayName: Glorfindel
Body: <p>A single knight or bishop usually isn't enough to force checkmate. However, I know there are certain positions where the defending side has his king in front of a rook pawn where a win can be forced.</p>
  
  <p>So I have two questions related to this:</p>
  
  <ul>
  <li>What is the longest forced win where the winning side has only a knight or bishop?</li>
  <li>Are there any nontrivial (i.e., not mate in 1) forced wins that don't involve the losing side having his king trapped in front of a rook pawn?</li>
  </ul>
  
Tags: <endgame><checkmate><knights><bishops>
Title: Longest forced win with just a Knight or Bishop
ThreadText: # Longest forced win with just a Knight or Bishop
  
  (Asked by: username_0 on 2018-01-24)
  
  A single knight or bishop usually isn't enough to force checkmate. However, I know there are certain positions where the defending side has his king in front of a rook pawn where a win can be forced.
  
  So I have two questions related to this:
  
  * What is the longest forced win where the winning side has only a knight or bishop?
  * Are there any nontrivial (i.e., not mate in 1) forced wins that don't involve the losing side having his king trapped in front of a rook pawn?
  
  **Tags:** endgame, checkmate, knights, bishops
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2018-01-24. Score: 9 | Accepted answer
  
  According to [this website](http://kirill-kryukov.com/chess/longest-checkmates/longest-checkmates.shtml), the longest checkmate for K+B vs. K+P is a simple mate in one, e.g.
  
  ```
  [FEN "8/8/8/8/8/8/p7/k1K1B3 w - - 0 1"]
  
  ```
  
  The K+N vs. K+P case is slightly more interesting, the following position is mate in seven:
  
  ```
  [FEN "8/8/8/8/p7/8/N7/k1K5 w - - 0 1"]
  
  1. Nb4 a3 2. Nc2+ Ka2 3. Nd4 Ka1 4. Kc2 Ka2 5. Ne2 Ka1 6. Nc1 a2 7. Nb3#
  
  ```
  
  You can play these endgames with online tablebases, e.g. [this one](http://www.shredderchess.com/online-chess/online-databases/endgame-database.html) from Shredder.
  
  > **Comments:**
  > **username_0**: Oh, now that's a helpful website. Looking at the 5-man ones, there appears to be one that isn't just a forced simplification to the above two positions: KB vs KNP. Neat.  
  
  ---
  
  ### Answer by username_1 on 2019-10-12. Score: 3
  
  The longest, **trivial** (trivial in terms of this question that is) known forced wins where White has just a knight or a bishop are 48 moves and 38 moves, respectively. These records can be seen in Grigory Popov’s Russain ["Chess Book Of Records"](http://superproblem.ru/archive/S_record-N.html) on superproblem.ru.
  
  ```
  [Title "Patrick O’Shea, The Problemist 1989, 1st Prize, Mate In 48"]
  [FEN "8/p2N4/p7/p7/p7/K5pp/1p3npk/6bn w - - 0 1"]
  
  1. Ne5 b1=N+ 2. Ka2 Nd2 3. Ka1 Nb3+ 4. Kb1 Nd2+ 5. Ka2 a3 6. Ka1 Nb3+ 7. Kb1 a2+ 8. Kxa2 Nd2 9. Ka1 Nb3+ 10. Kb1 Nd2+ 11. Ka2 a4 12. Ka1 Nb3+ 13. Kb1 Nd2+ 14. Ka2 a3 15. Ka1 Nb3+ 16. Kb1 a2+ 17. Kxa2 Nd2 18. Ka1 Nb3+ 19. Kb1 Nd2+ 20. Ka2 a5 21. Ka1 Nb3+ 22. Kb1 Nd2+ 23. Ka2 a4 24. Ka1 Nb3+ 25. Kb1 Nd2+ 26. Ka2 a3 27. Ka1 Nb3+ 28. Kb1 a2+ 29. Kxa2 Nd2 30. Ka1 Nb3+ 31. Kb1 Nd2+ 32. Ka2 a6 33. Ka1 Nb3+ 34. Kb1 Nd2+ 35. Ka2 a5 36. Ka1 Nb3+ 37. Kb1 Nd2+ 38. Ka2 a4 39. Ka1 Nb3+ 40. Kb1 Nd2+ 41. Ka2 a3 42. Ka1 Nb3+ 43. Kb1 a2+ 44. Kxa2 Nd2 45. Ka1 Nb3+ 46. Kb1 Nd2+ 47. Ka2 Nb1 48. Nf3#
  
  ```
  
  ---
  
  ```
  [Title "ChristopherJeremy Morse, The Problemist 1978, Mate In 38"]
  [FEN "8/2p2p2/5p2/1B3p2/5p2/p2n4/kp1K1p2/b4r2 w - - 0 1"]
  
  1. Bc4+ Kb1 2. Bxd3+ Ka2 3. Bc4+ Kb1 4. Bxf1 Ka2 5. Bc4+ Kb1 6. Kd1 f3 7. Kd2 f4 8. Kd1 f5 9. Kd2 f6 10. Kd1 c6 11. Kd2 c5 12. Kd1 f1=Q+ 13. Bxf1 Ka2 14. Bc4+ Kb1 15. Kd2 f2 16. Kd1 f3 17. Kd2 f4 18. Kd1 f5 19. Kd2 f1=Q 20. Bxf1 Ka2 21. Bc4+ Kb1 22. Kd1 f2 23. Kd2 f3 24. Kd1 f4 25. Kd2 f1=Q 26. Bxf1 Ka2 27. Bc4+ Kb1 28. Kd1 f2 29. Kd2 f3 30. Kd1 f1=Q+ 31. Bxf1 Ka2 32. Bc4+ Kb1 33. Kd2 f2 34. Kd1 f1=Q+ 35. Bxf1 Ka2 36. Bc4+ Kb1 37. Kd2 a2 38. Bd3#
  
  ```
  
  
  ---
  
  