Answers.Body: <p>@DM showed one possibility, which would also work with bishops (and on various other places on the board, with the three pieces at corners of a square). The only other option is with knights:</p>
  <pre><code>[FEN &quot;8/1k6/8/8/5N2/8/1N3NK1/8 w - - 0 1&quot;]
  
  1. Nf2d3
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-12-25T11:20:14.943Z
Answers.Text: The example with knights is best, only one promotion needed.
Answers.UserDisplayName: bof
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-01-04T03:46:53.413Z
Answers.Text: Why are knights "the only other option?" Surely it can occur with rooks...
Answers.UserDisplayName: Brian McCutchon
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-01-04T07:02:55.243Z
Answers.Text: @BrianMcCutchon no, you need some kind of diagonal movement for this kind of ambiguity.
Answers.UserDisplayName: Glorfindel
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Answers.CreationDate: 2020-12-25T09:18:25.940Z
Answers.LastActivityDate: 2020-12-25T09:18:25.940Z
Answers.UserDisplayName: Glorfindel
Answers.Body: <p>Yes, it's possible for a piece to need both the rank and file to distinguish it, although it's rare. For example:</p>
  <pre><code>[FEN &quot;8/1k6/8/8/5Q2/8/3Q1QK1/8 w - - 0 1&quot;]
  
  1.Qf2e3
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-12-25T09:17:23.803Z
Answers.Text: Incidentally, I once made a chess problem stipulating to play the fastest game leading to such a situation; try to find it!
Answers.UserDisplayName: Hauke Reddmann
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-12-25T11:02:39.500Z
Answers.Text: @HaukeReddmann I'm sure this is not it, but the fastest one I find is 11 moves, White's moves being 1. e4 2. exd5 3. Nc3 4. d6 5. dxe7 6. exf8N 7. Ne6 8. Ng5 9. Nge2 10. Ng3 11. Ng3e4.
Answers.UserDisplayName: bof
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-12-25T14:21:12.660Z
Answers.Text: Thanks for the quick answer. Clear and unambiguous!
Answers.UserDisplayName: Blunt Jackson
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Answers.CreationDate: 2020-12-25T04:03:38.597Z
Answers.LastActivityDate: 2020-12-25T04:03:38.597Z
Answers.UserDisplayName: D M
Body: <p>The PGN &quot;Standard&quot; (if you want to call it that, because it is very flawed and seems out of date), states:</p>
  <blockquote>
  <ul>
  <li>First, if the moving pieces can be distinguished by their originating files, the originating file letter of the moving piece is
  inserted immediately after the moving piece letter.</li>
  <li>Second (when the first step fails), if the moving pieces can be distinguished by their originating ranks, the originating rank digit
  of the moving piece is inserted immediately after the moving piece
  letter.</li>
  <li>Third (when both the first and the second steps fail), the two character square coordinate of the originating square of the moving
  piece is inserted immediately after the moving piece letter.</li>
  </ul>
  </blockquote>
  <p>What I want to know is this: what situation could give rise to the third case?</p>
  <p>As I think this through, I cannot for the life of me think up a scenario that the first or second disambiguation rules wouldn't comprehensively cover.</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-01-21T19:23:51.613Z
Comments.Text: Does anyone know if the third case every happened in a real game?
Comments.UserDisplayName: domotorp
Tags: <pgn><notation>
Title: When are both the rank and file required for disambiguation of a move in PGN/SAN?
ThreadText: # When are both the rank and file required for disambiguation of a move in PGN/SAN?
  
  (Asked by: username_0 on 2020-12-25)
  
  The PGN "Standard" (if you want to call it that, because it is very flawed and seems out of date), states:
  
  > * First, if the moving pieces can be distinguished by their originating files, the originating file letter of the moving piece is
  >   inserted immediately after the moving piece letter.
  > * Second (when the first step fails), if the moving pieces can be distinguished by their originating ranks, the originating rank digit
  >   of the moving piece is inserted immediately after the moving piece
  >   letter.
  > * Third (when both the first and the second steps fail), the two character square coordinate of the originating square of the moving
  >   piece is inserted immediately after the moving piece letter.
  
  What I want to know is this: what situation could give rise to the third case?
  
  As I think this through, I cannot for the life of me think up a scenario that the first or second disambiguation rules wouldn't comprehensively cover.
  
  **Tags:** pgn, notation
  
  > **Comments:**
  > **username_1**: Does anyone know if the third case every happened in a real game?  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_5 on 2020-12-25. Score: 8 | Accepted answer
  
  Yes, it's possible for a piece to need both the rank and file to distinguish it, although it's rare. For example:
  [FEN "8/1k6/8/8/5Q2/8/3Q1QK1/8 w - - 0 1"]
  
  1.Qf2e3
  
  > **Comments:**
  > **username_6**: Incidentally, I once made a chess problem stipulating to play the fastest game leading to such a situation; try to find it!  
  > **username_3**: @HaukeReddmann I'm sure this is not it, but the fastest one I find is 11 moves, White's moves being 1. e4 2. exd5 3. Nc3 4. d6 5. dxe7 6. exf8N 7. Ne6 8. Ng5 9. Nge2 10. Ng3 11. Ng3e4.  
  > **username_0**: Thanks for the quick answer. Clear and unambiguous!  
  
  ---
  
  ### Answer by username_2 on 2020-12-25. Score: 7
  
  @DM showed one possibility, which would also work with bishops (and on various other places on the board, with the three pieces at corners of a square). The only other option is with knights:
  [FEN "8/1k6/8/8/5N2/8/1N3NK1/8 w - - 0 1"]
  
  1. Nf2d3
  
  > **Comments:**
  > **username_3**: The example with knights is best, only one promotion needed.  
  > **username_4**: Why are knights "the only other option?" Surely it can occur with rooks...  
  > **username_2**: @BrianMcCutchon no, you need some kind of diagonal movement for this kind of ambiguity.  
  
  ---
  
  