Answers.Body: <p>In one of my books I found this "uncredited" problem, it is probably not the problem you are referring to but I thought you may find it interesting, hope you like it.</p>
  
  <p>2018 Update, thanks to user @Evargalo for adding some light about the author, we can know it was composed by Gijs van Breukelen.</p>
  
  <pre><code>8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1
  
  1. Nf6+ Kg7 2. Nh5+ Kg6 3. Bc2+ Kxh5 4. d8=Q Nf7+ 5. Ke6 Nxd8+ 6. Kf5 e2 7.Be4 e1=N 8. Bd5 c2 9. Bc4 c1=N 10. Bb5 Nc7 11. Ba4 Ne2 12. Bd1 Nf3 13. Bxe2
  </code></pre>
  
  <p>White, with material inferiority, must act energically:</p>
  
  <p><strong><code>1.Nf6+ Kg7</code></strong> if 1...Kg6 2.Bc2+! Kg7 3.Nh5+ Kf7 4.d8=Q and black has lost the possibility of check on f7.</p>
  
  <p><strong><code>2.Nh5+ Kg6</code></strong>  The black King cannot go to the last rank, d7 will crown with check.</p>
  
  <p><strong><code>3.Bc2+ Kxh5 4. d8=Q Nf7+ 5. Ke6 Nxd8+ 6. Kf5</code></strong> This is the first part of the study: White has accomplished to place the black king in a mate position. In the next set of moves each defensive move by black will be forced.</p>
  
  <p><strong><code>6...e2 7.Be4!</code></strong> Threat on f3 the only move to prevent checkmate is a sub-promotion.</p>
  
  <p><strong><code>7...e1=N 8.Bd5!!</code></strong> Threats 9.Bc4 10.Be2# </p>
  
  <p><strong><code>8...c2 9.Bc4 c1=N! 10.Bb5!</code></strong> With the idea of checkmate on e8</p>
  
  <p><strong><code>10...Nc7 11.Ba4!</code></strong> and 4 Knights cannot prevent checkmate</p>
  
  <p><strong><code>11...Ne2 12.Bd1 Nf3 13.Bxe2</code></strong> followed by 14.Bxf3#</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2012-12-31T04:09:22.663Z
Answers.Text: Excellent, thanks for taking the time to share
Answers.UserDisplayName: NeilS
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2018-02-28T07:32:55.007Z
Answers.Text: You should credit the author of this beautiful problem.
Answers.UserDisplayName: Evargalo
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2018-03-04T18:58:27.693Z
Answers.Text: @Evargalo the author of the study is unknown, hence the NN-NN (no name), the author of the book however is Mexican IM Guil Russek, "Ajedrez; Finales Artisticos"
Answers.UserDisplayName: Helio
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2018-03-04T19:55:31.547Z
Answers.Text: The author of this study is Gijs van Breukelen. It was first published in the reviewSchakend Nederland in 1990.
  https://en.chessbase.com/post/solution-to-a-truly-remarkable-study
Answers.UserDisplayName: Evargalo
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2018-03-06T18:47:42.163Z
Answers.Text: I didn't see this post before, but a few days ago this study was posted as a puzzle on [Puzzling Stack Exchange](https://puzzling.stackexchange.com/q/61140/11110).
Answers.UserDisplayName: Glorfindel
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-09-03T14:20:35.927Z
Answers.Text: Why is `4. ... Nf7+` the best move?
Answers.UserDisplayName: user21820
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Answers.CreationDate: 2012-12-31T01:46:51.597Z
Answers.LastActivityDate: 2018-03-06T02:20:15.617Z
Answers.LastEditDate: 2018-03-06T02:20:15.617Z
Answers.UserDisplayName: Helio
Answers.Body: <p>You must be thinking of this classic Korolkov study (I-II Prize &quot;64&quot; 1937, according to Chernev's <em>Chessboard Magic!</em>; P1288537 in PDB).  It's not a problem, nor in 7 moves, but seems to match the rest closely:</p>
  <pre><code>[Title &quot;White to play and win (Korolkov 1937)&quot;]
  [Fen &quot;4N3/2PP2P1/6b2/2bN2R1/6pk/p7/K1pn4/8 w - - 0 0&quot;]
  
  1.Rh5+ Kxh5 2.Nf4+ Kh6 3.g8=N+ Kh7 4.Ngf6+ Kh6 5.Nxg4+ Kh7 6.Nef6+ Kg7 7.Ne6+ Kf7 8.d8=N+ Ke7 9.c8=N#
  </code></pre>
  <p>In the starting diagram Black threatens mate with, appropriately, a checking Knight promotion: c1N+ and either Ndb3# or Bd4+ and mate.  If Black diverges from the main line then White usually promotes a Queen with check; exceptions are 1...Kg3 2.Rh1 and 4...Kh8 5.Nxg6#.</p>
  <p>It is possible that youur friend showed you the problem without the first two moves, thus making you think that it was a mate in 7.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
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Answers.LastEditDate: 2020-09-03T11:33:55.543Z
Answers.UserDisplayName: Noam D. Elkies
Answers.Body: <p>I don't know about 5 knights, but it has been shown that 3 knights and a king can force mate.</p>
  
  <p>The method is given in Reuben Fine's Basic Chess Endings, ISBN 0-679-14002-6, my copy of which seems to have disappeared, along with the memory of its contents in this instance. I do however, distinctly remember that this endgame situation is covered in the book.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2012-12-30T23:32:55.447Z
Answers.Text: Thank you. A few more thoughts: (1) I think it was mate in seven. (2) Unusually, every white move is forced because there is a mate threat from black. (3) Unless I have the memory of the board upside down, the black king starts in the middle of the board and ends up on his sixth or even seventh rank surrounded by two pairs of white knights protecting each other and the fifth one executing the mate. (4) The white king is somewhere really odd like h7 and the black mate threat comes from a minor piece - a bishop, perhaps?
Answers.UserDisplayName: NeilS
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Answers.UserDisplayName: mschultz
Body: <p>Many years ago, I was shown a problem involving three white pawns promoting to knights and ending up with a ring of five knights encircling the mated king. Does anybody know the starting position?</p>
  
  <p>A few more thoughts:<br>
  (1) I think it was mate in seven.  </p>
  
  <p>(2) Unusually, every white move is forced because there is a mate threat from black.  </p>
  
  <p>(3) Unless I have the memory of the board upside down, the black king starts in the middle of the board and ends up on his sixth or even seventh rank surrounded by two pairs of white knights protecting each other and the fifth one executing the mate.  </p>
  
  <p>(4) The white king is somewhere really odd like h7 and the black mate threat comes from a minor piece - a bishop, perhaps?</p>
  
Tags: <knights>
Title: Five Knights Problem
ThreadText: # Five Knights Problem
  
  (Asked by: username_0 on 2012-12-30)
  
  Many years ago, I was shown a problem involving three white pawns promoting to knights and ending up with a ring of five knights encircling the mated king. Does anybody know the starting position?
  
  A few more thoughts:  
  (1) I think it was mate in seven.
  
  (2) Unusually, every white move is forced because there is a mate threat from black.
  
  (3) Unless I have the memory of the board upside down, the black king starts in the middle of the board and ends up on his sixth or even seventh rank surrounded by two pairs of white knights protecting each other and the fifth one executing the mate.
  
  (4) The white king is somewhere really odd like h7 and the black mate threat comes from a minor piece - a bishop, perhaps?
  
  **Tags:** knights
  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_1 on 2012-12-31. Score: 13
  
  In one of my books I found this "uncredited" problem, it is probably not the problem you are referring to but I thought you may find it interesting, hope you like it.
  2018 Update, thanks to user @username_2 for adding some light about the author, we can know it was composed by Gijs van Breukelen.
  8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1
  
  1. Nf6+ Kg7 2. Nh5+ Kg6 3. Bc2+ Kxh5 4. d8=Q Nf7+ 5. Ke6 Nxd8+ 6. Kf5 e2 7.Be4 e1=N 8. Bd5 c2 9. Bc4 c1=N 10. Bb5 Nc7 11. Ba4 Ne2 12. Bd1 Nf3 13. Bxe2
  
  White, with material inferiority, must act energically:
  1.Nf6+ Kg7 if 1...Kg6 2.Bc2+! Kg7 3.Nh5+ Kf7 4.d8=Q and black has lost the possibility of check on f7.
  2.Nh5+ Kg6  The black King cannot go to the last rank, d7 will crown with check.
  3.Bc2+ Kxh5 4. d8=Q Nf7+ 5. Ke6 Nxd8+ 6. Kf5 This is the first part of the study: White has accomplished to place the black king in a mate position. In the next set of moves each defensive move by black will be forced.
  6...e2 7.Be4! Threat on f3 the only move to prevent checkmate is a sub-promotion.
  7...e1=N 8.Bd5!! Threats 9.Bc4 10.Be2# 
  8...c2 9.Bc4 c1=N! 10.Bb5! With the idea of checkmate on e8
  10...Nc7 11.Ba4! and 4 Knights cannot prevent checkmate
  11...Ne2 12.Bd1 Nf3 13.Bxe2 followed by 14.Bxf3#
  
  > **Comments:**
  > **username_0**: Excellent, thanks for taking the time to share  
  > **username_2**: You should credit the author of this beautiful problem.  
  > **username_1**: @username_2 the author of the study is unknown, hence the NN-NN (no name), the author of the book however is Mexican IM Guil Russek, "Ajedrez; Finales Artisticos"  
  > **username_2**: The author of this study is Gijs van Breukelen. It was first published in the reviewSchakend Nederland in 1990. https://en.chessbase.com/post/solution-to-a-truly-remarkable-study  
  > **username_3**: I didn't see this post before, but a few days ago this study was posted as a puzzle on [Puzzling Stack Exchange](https://puzzling.stackexchange.com/q/61140/11110).  
  > **username_4**: Why is `4. ... Nf7+` the best move?  
  
  ---
  
  ### Answer by username_5 on 2018-03-10. Score: 11
  
  You must be thinking of this classic Korolkov study (I-II Prize "64" 1937, according to Chernev's Chessboard Magic!; P1288537 in PDB).  It's not a problem, nor in 7 moves, but seems to match the rest closely:
  [Title "White to play and win (Korolkov 1937)"]
  [Fen "4N3/2PP2P1/6b2/2bN2R1/6pk/p7/K1pn4/8 w - - 0 0"]
  
  1.Rh5+ Kxh5 2.Nf4+ Kh6 3.g8=N+ Kh7 4.Ngf6+ Kh6 5.Nxg4+ Kh7 6.Nef6+ Kg7 7.Ne6+ Kf7 8.d8=N+ Ke7 9.c8=N#
  
  In the starting diagram Black threatens mate with, appropriately, a checking Knight promotion: c1N+ and either Ndb3# or Bd4+ and mate.  If Black diverges from the main line then White usually promotes a Queen with check; exceptions are 1...Kg3 2.Rh1 and 4...Kh8 5.Nxg6#.
  It is possible that youur friend showed you the problem without the first two moves, thus making you think that it was a mate in 7.
  
  
  ---
  
  ### Answer by username_6 on 2012-12-30. Score: 3
  
  I don't know about 5 knights, but it has been shown that 3 knights and a king can force mate.
  
  The method is given in Reuben Fine's Basic Chess Endings, ISBN 0-679-14002-6, my copy of which seems to have disappeared, along with the memory of its contents in this instance. I do however, distinctly remember that this endgame situation is covered in the book.
  
  > **Comments:**
  > **username_0**: Thank you. A few more thoughts: (1) I think it was mate in seven. (2) Unusually, every white move is forced because there is a mate threat from black. (3) Unless I have the memory of the board upside down, the black king starts in the middle of the board and ends up on his sixth or even seventh rank surrounded by two pairs of white knights protecting each other and the fifth one executing the mate. (4) The white king is somewhere really odd like h7 and the black mate threat comes from a minor piece - a bishop, perhaps?  
  
  ---
  
  