Answers.Body: <p>This puzzle was by Tibor Orban in 1976, and is a great introductory puzzle for those who have never come across a proof game before. In its miniature form, it still shows two elementary technical features: Tempo Loss and Switchback. Tempo is already discussed: there are shorter (non-unique) solutions in 3.0 &amp; 3.5 moves. Switchback is where the Black King leaves his starting square and returns to it. Apart from their artistic effect, these two features also serve to conceal the solution better. </p>
  
  <p>Chess problems are a bit like high diving: you are trying to harmoniously combine a sequence of challenging effects before you hit the water. (See <a href="http://whdf.com/Information/WHDF%20formula%20and%20components%20for%20dd%20calculation%20EC%20090724.pdf" rel="noreferrer">here</a>. One difference is that in chess problems there is not the same rigorous point counting: appreciation is more subjective.)</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-05-26T12:42:02.610Z
Answers.Text: +1 for the attribution and mentioning two features. This PG4.0 by Orbán is unusual in that, although the specified length is not the shortest requred to reach the diagram, there is a unique solution.
Answers.UserDisplayName: Rosie F
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-09-07T17:38:18.540Z
Answers.LastActivityDate: 2015-09-07T19:27:57.200Z
Answers.LastEditDate: 2015-09-07T19:27:57.200Z
Answers.UserDisplayName: Laska
Answers.Body: <p>Interesting puzzle, particularly the requirement that the number of moves be exactly four per side.  But for that, a three-move-per-side solution would be easy:</p>
  
  <pre><code>rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
  
  1. e4 c6 2. Bc4 e6 3. Bxe6 dxe6
  </code></pre>
  
  <p>The difficulty is that all three of black's moves are pawn moves, and wasting a turn moving anything else would force Black to waste <em>another</em> turn moving it back.  It becomes apparent therefore that two of black's moves must be with something other than pawns, which in turn implies that White must capture d7 at its original location.  That capture cannot occur prior to White's third move, and cannot occur after c6.  Thus, Black will have only one move available after c6, and must move something off its original position before C6.  That piece must return to its original spot on its last move, and that spot must contain the bishop.  The only Black piece whose original spot White's bishop could reach are his king and his light-square bishop; of those, only the former can move before turn 3.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-03-16T20:21:45.883Z
Answers.LastActivityDate: 2014-03-16T20:21:45.883Z
Answers.UserDisplayName: supercat
Answers.Body: <p>Dag Oskar Madsen's (quite generous) hint:</p>
  
  <blockquote>
    <p>The last move was king takes e-eight.</p>
  </blockquote>
  
  <p>And here's the full solution:</p>
  
  <blockquote>
    <p>Pawn to e-four, pawn to e-six, bishop to b-five, king to e-seven, bishop takes d-seven, pawn to c-six, bishop to e-eight, king takes e-eight.</p>
  </blockquote>
  
  <pre><code>rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
  
  1. e4 e6 2. Bb5 Ke7 3. Bxd7 c6 4. Be8 Kxe8  
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-11-09T16:26:53.420Z
Answers.LastActivityDate: 2013-11-24T16:14:05.660Z
Answers.LastEditDate: 2013-11-24T16:14:05.660Z
Answers.UserDisplayName: ETD
Body: <p>In the following position, each side has made exactly 4 moves (8 in total).</p>
  
  <pre><code>[fen "rnbqkbnr/pp3ppp/2p1p3/8/4P3/8/PPPP1PPP/RNBQK1NR w KQkq - 0 1"]
  </code></pre>
  
  <p>I need to find what these moves were.</p>
  
Tags: <problems><retrograde-analysis>
Title: Problem: reconstruct the game
ThreadText: # Problem: reconstruct the game
  
  (Asked by: username_0 on 2013-11-09)
  
  In the following position, each side has made exactly 4 moves (8 in total).
  [fen "rnbqkbnr/pp3ppp/2p1p3/8/4P3/8/PPPP1PPP/RNBQK1NR w KQkq - 0 1"]
  
  I need to find what these moves were.
  
  **Tags:** problems, retrograde-analysis
  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_4 on 2013-11-09. Score: 9 | Accepted answer
  
  Dag Oskar Madsen's (quite generous) hint:
  
  The last move was king takes e-eight.
  
  And here's the full solution:
  
  Pawn to e-four, pawn to e-six, bishop to b-five, king to e-seven, bishop takes d-seven, pawn to c-six, bishop to e-eight, king takes e-eight.
  
  rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
  
  1. e4 e6 2. Bb5 Ke7 3. Bxd7 c6 4. Be8 Kxe8
  
  
  ---
  
  ### Answer by username_1 on 2015-09-07. Score: 9
  
  This puzzle was by Tibor Orban in 1976, and is a great introductory puzzle for those who have never come across a proof game before. In its miniature form, it still shows two elementary technical features: Tempo Loss and Switchback. Tempo is already discussed: there are shorter (non-unique) solutions in 3.0 & 3.5 moves. Switchback is where the Black King leaves his starting square and returns to it. Apart from their artistic effect, these two features also serve to conceal the solution better.
  
  Chess problems are a bit like high diving: you are trying to harmoniously combine a sequence of challenging effects before you hit the water. (See [here](http://whdf.com/Information/WHDF%20formula%20and%20components%20for%20dd%20calculation%20EC%20090724.pdf). One difference is that in chess problems there is not the same rigorous point counting: appreciation is more subjective.)
  
  > **Comments:**
  > **username_2**: +1 for the attribution and mentioning two features. This PG4.0 by Orbán is unusual in that, although the specified length is not the shortest requred to reach the diagram, there is a unique solution.  
  
  ---
  
  ### Answer by username_3 on 2014-03-16. Score: 7
  
  Interesting puzzle, particularly the requirement that the number of moves be exactly four per side.  But for that, a three-move-per-side solution would be easy:
  rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
  
  1. e4 c6 2. Bc4 e6 3. Bxe6 dxe6
  
  The difficulty is that all three of black's moves are pawn moves, and wasting a turn moving anything else would force Black to waste another turn moving it back.  It becomes apparent therefore that two of black's moves must be with something other than pawns, which in turn implies that White must capture d7 at its original location.  That capture cannot occur prior to White's third move, and cannot occur after c6.  Thus, Black will have only one move available after c6, and must move something off its original position before C6.  That piece must return to its original spot on its last move, and that spot must contain the bishop.  The only Black piece whose original spot White's bishop could reach are his king and his light-square bishop; of those, only the former can move before turn 3.
  
  
  ---
  
  