Answers.Body: <p>For a partial answer, here are a semi-unique sequence sin 11 moves. They are no doubt revealing of the true solution's strategy.</p>
  <pre><code>[FEN &quot;&quot;]
  
  1. e4 h5 2. Qxh5 Rxh5 3. g4 Re5 4. Bc4 Rxe4+ 5. Kf1 Re1+ 6. Kg2 Rxc1 7. g5 Re1 8. Be6 Rxe6 9. g6 Rxg6+ 10. Kf1 Rh6 11. Ke1 Rh8
  </code></pre>
  <p>Or this.</p>
  <pre><code>[FEN &quot;&quot;]
  
  1. e3 h5 2. Qxh5 Rxh5 3. g3 Rh3 4. Bd3 Rxg3 5. Kf1 Rxe3 6. Kg2 Re1 7. Bf5 Rxc1  8. Bg4 Re1 9. Bh3 Re3 10. Kf1 Rxh3 11. Ke1 Rh8
  </code></pre>
  <p>And this.</p>
  <pre><code>[FEN &quot;&quot;]
  
  1. e4 h5 2. Qxh5 Rxh5 3. g3 Re5 4. Bh3 Rxe4+ 5. Kf1 Re1+ 6. Kg2 Rxc1 7. Kf3 Re1  8. Kg2 Re3 9. Kf1 Rxg3 10. Ke2 Rxh3 11. Ke1 Rh8
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-25T17:43:52.863Z
Answers.Text: Good experiments! But the actual solution is a lot shorter!
Answers.UserDisplayName: Laska
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-25T17:31:07.313Z
Answers.LastActivityDate: 2020-11-25T18:37:24.533Z
Answers.LastEditDate: 2020-11-25T18:37:24.533Z
Answers.UserDisplayName: Rewan Demontay
Answers.Body: <p>I have no idea about this kind of problems, but my guess would be something like this.</p>
  <pre><code>[FEN &quot;&quot;]
  
  1. g4 h5 2. Bg2 hxg4 3. Bf3 gxf3 4. Kf1 fxe2+ 5. Kg2 exd1=R 6. Kf3 Rxc1 7. Ke2 Re1+ 8. Kxe1
  </code></pre>
  <p>Is that unique? I have no idea.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-25T18:59:56.963Z
Answers.Text: @RewanDemontay thanks for the edit, how does that work? Simply adding [FEN ""] before the moves? And then presumably enter the position in the quotation marks if it's not the starting position.
Answers.UserDisplayName: koedem
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-25T19:10:51.807Z
Answers.Text: Very nice - and yes it’s unique. Can you make sure this is concealed by spoiler protection, so others can have a go
Answers.UserDisplayName: Laska
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-25T19:16:39.653Z
Answers.Text: @Laska do you happen to know if there is a way to hide a diagram? So apparently spoilers can be used through the usage of >! ? But then the diagram is gone again.
Answers.UserDisplayName: koedem
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-26T08:54:04.190Z
Answers.Text: @koedem I don't know how to hide a diagram: maybe ask in meta
Answers.UserDisplayName: Laska
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-26T09:29:50.210Z
Answers.Text: Spoilers are very limited in what formatting they support; the replayer won't work in them. I feel that people who visit the page *know* there must be solutions below, so a spoiler isn't really necessary.
Answers.UserDisplayName: Glorfindel
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-11-25T18:23:09.963Z
Answers.LastActivityDate: 2020-11-25T19:14:31.880Z
Answers.LastEditDate: 2020-11-25T19:14:31.880Z
Answers.UserDisplayName: koedem
Body: <p>&quot;Homebase&quot; is where all the surviving pieces are apparently on their starting squares. Here is a very easy new example proof game: can you find the unique shortest game that leads to this position?</p>
  <pre><code>[Title &quot;A.Buchanan 26-11-2020 Facebook: shortest proof game?&quot;]
  [FEN &quot;rnbqkbnr/ppppppp1/8/8/8/8/PPPP1P1P/RN2K1NR w - - 0 1&quot;]
  </code></pre>
  <p>Yes c1 is empty!</p>
  
Tags: <problems><retrograde-analysis>
Title: How many moves needed to reach this position?
ThreadText: # How many moves needed to reach this position?
  
  (Asked by: username_0 on 2020-11-25)
  
  "Homebase" is where all the surviving pieces are apparently on their starting squares. Here is a very easy new example proof game: can you find the unique shortest game that leads to this position?
  
  ```
  [Title "A.Buchanan 26-11-2020 Facebook: shortest proof game?"]
  [FEN "rnbqkbnr/ppppppp1/8/8/8/8/PPPP1P1P/RN2K1NR w - - 0 1"]
  
  ```
  
  Yes c1 is empty!
  
  **Tags:** problems, retrograde-analysis
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2020-11-25. Score: 4 | Accepted answer
  
  I have no idea about this kind of problems, but my guess would be something like this.
  
  ```
  [FEN ""]
  
  1. g4 h5 2. Bg2 hxg4 3. Bf3 gxf3 4. Kf1 fxe2+ 5. Kg2 exd1=R 6. Kf3 Rxc1 7. Ke2 Re1+ 8. Kxe1
  
  ```
  
  Is that unique? I have no idea.
  
  > **Comments:**
  > **username_2**: @username_1 thanks for the edit, how does that work? Simply adding [FEN ""] before the moves? And then presumably enter the position in the quotation marks if it's not the starting position.  
  > **username_0**: Very nice - and yes it’s unique. Can you make sure this is concealed by spoiler protection, so others can have a go  
  > **username_2**: @username_0 do you happen to know if there is a way to hide a diagram? So apparently spoilers can be used through the usage of >! ? But then the diagram is gone again.  
  > **username_0**: @username_2 I don't know how to hide a diagram: maybe ask in meta  
  > **username_3**: Spoilers are very limited in what formatting they support; the replayer won't work in them. I feel that people who visit the page *know* there must be solutions below, so a spoiler isn't really necessary.  
  
  ---
  
  ### Answer by username_1 on 2020-11-25. Score: 2
  
  For a partial answer, here are a semi-unique sequence sin 11 moves. They are no doubt revealing of the true solution's strategy.
  
  ```
  [FEN ""]
  
  1. e4 h5 2. Qxh5 Rxh5 3. g4 Re5 4. Bc4 Rxe4+ 5. Kf1 Re1+ 6. Kg2 Rxc1 7. g5 Re1 8. Be6 Rxe6 9. g6 Rxg6+ 10. Kf1 Rh6 11. Ke1 Rh8
  
  ```
  
  Or this.
  
  ```
  [FEN ""]
  
  1. e3 h5 2. Qxh5 Rxh5 3. g3 Rh3 4. Bd3 Rxg3 5. Kf1 Rxe3 6. Kg2 Re1 7. Bf5 Rxc1  8. Bg4 Re1 9. Bh3 Re3 10. Kf1 Rxh3 11. Ke1 Rh8
  
  ```
  
  And this.
  
  ```
  [FEN ""]
  
  1. e4 h5 2. Qxh5 Rxh5 3. g3 Re5 4. Bh3 Rxe4+ 5. Kf1 Re1+ 6. Kg2 Rxc1 7. Kf3 Re1  8. Kg2 Re3 9. Kf1 Rxg3 10. Ke2 Rxh3 11. Ke1 Rh8
  
  ```
  
  > **Comments:**
  > **username_0**: Good experiments! But the actual solution is a lot shorter!  
  
  ---
  
  