Answers.Body: <p>I don't think so, because, for example, the french defence can be reached in the following way: <code>1.Nf3 Nf6 2.Ng1 Ng8 3.Nc3 Nc6 4.Nb1 Nb8 5. e4 e6</code>. Of course, the knight moves can be repeated more times, with different combinations. Also, <code>e4</code> can be delayed with <code>e3</code>, when black "wastes" a move with a knight. Thus, it's not too useful to have such a resource.</p>
  
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Answers.CreationDate: 2013-01-21T18:11:04.643Z
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Answers.Body: <p>The point from <a href="https://chess.stackexchange.com/a/1909/167">chubbycantorset's answer</a> about the futility of seeking the number of <em>all</em> ways to reach a position is a good one. Scid has a way of offering more limited (and more practically useful anyway) information than that. Its <a href="http://scid.sourceforge.net/help/Reports.html" rel="nofollow noreferrer">Opening Report</a> tool allows you to input a position, and then generate a comprehensive statistical report covering games that reached that position (in whatever database you have open). Among the data presented is a tally of how many move-orders were used to reach the position in question <em>that appeared in actual games from the database</em>, as well as a list of the most popular.</p>
  
  <p>For instance, in my big database of millions of games, when I generate a report for the standard Sicilian Scheveningen position</p>
  
  <pre><code>[fen "rnbqkb1r/pp3ppp/3ppn2/8/3NP3/2N5/PPP2PPP/R1BQKB1R w KQkq - 0 1"]
  </code></pre>
  
  <p>part of the information I receive is as follows, where the numbers in parentheses indicate how many games feature the move-order in question:</p>
  
  <pre><code>There were 82 move orders reaching this position. The top 8 are:
    1:  1. e4  c5 2. Nf3  e6 3. d4  cxd4 4. Nxd4  Nf6 5. Nc3  d6 (18538)
    2:  1. e4  c5 2. Nf3  d6 3. d4  cxd4 4. Nxd4  Nf6 5. Nc3  e6 (11028)
    3:  1. e4  c5 2. Nf3  d6 3. d4  Nf6 4. Nc3  cxd4 5. Nxd4  e6 (646)
    4:  1. e4  c5 2. Nf3  e6 3. Nc3  d6 4. d4  cxd4 5. Nxd4  Nf6 (597)
    5:  1. e4  c5 2. Nc3  e6 3. Nf3  d6 4. d4  cxd4 5. Nxd4  Nf6 (258)
    6:  1. e4  c5 2. Nf3  e6 3. d4  cxd4 4. Nxd4  d6 5. Nc3  Nf6 (144)
    7:  1. e4  e6 2. d4  c5 3. Nf3  cxd4 4. Nxd4  Nf6 5. Nc3  d6 (117)
    8:  1. e4  c5 2. Nf3  d6 3. Nc3  Nf6 4. d4  cxd4 5. Nxd4  e6 (92)
  </code></pre>
  
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Answers.Text: Yeah I think I've seen that position a few times. :P I like #7, it starts out with the french defense, lol.
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Body: <p>Is there a resource (book/online) that shows how many ways an opening can be reached?</p>
  
Tags: <opening>
Title: A resource that shows how many ways an opening can be reached?
ThreadText: # A resource that shows how many ways an opening can be reached?
  
  (Asked by: username_0 on 2013-01-21)
  
  Is there a resource (book/online) that shows how many ways an opening can be reached?
  
  **Tags:** opening
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2013-01-21. Score: 8 | Accepted answer
  
  The point from [username_1's answer](https://chess.stackexchange.com/a/1909/167) about the futility of seeking the number of *all* ways to reach a position is a good one. Scid has a way of offering more limited (and more practically useful anyway) information than that. Its [Opening Report](http://scid.sourceforge.net/help/Reports.html) tool allows you to input a position, and then generate a comprehensive statistical report covering games that reached that position (in whatever database you have open). Among the data presented is a tally of how many move-orders were used to reach the position in question *that appeared in actual games from the database*, as well as a list of the most popular.
  
  For instance, in my big database of millions of games, when I generate a report for the standard Sicilian Scheveningen position
  
  ```
  [fen "rnbqkb1r/pp3ppp/3ppn2/8/3NP3/2N5/PPP2PPP/R1BQKB1R w KQkq - 0 1"]
  
  ```
  
  part of the information I receive is as follows, where the numbers in parentheses indicate how many games feature the move-order in question:
  
  ```
  There were 82 move orders reaching this position. The top 8 are:
    1:  1. e4  c5 2. Nf3  e6 3. d4  cxd4 4. Nxd4  Nf6 5. Nc3  d6 (18538)
    2:  1. e4  c5 2. Nf3  d6 3. d4  cxd4 4. Nxd4  Nf6 5. Nc3  e6 (11028)
    3:  1. e4  c5 2. Nf3  d6 3. d4  Nf6 4. Nc3  cxd4 5. Nxd4  e6 (646)
    4:  1. e4  c5 2. Nf3  e6 3. Nc3  d6 4. d4  cxd4 5. Nxd4  Nf6 (597)
    5:  1. e4  c5 2. Nc3  e6 3. Nf3  d6 4. d4  cxd4 5. Nxd4  Nf6 (258)
    6:  1. e4  c5 2. Nf3  e6 3. d4  cxd4 4. Nxd4  d6 5. Nc3  Nf6 (144)
    7:  1. e4  e6 2. d4  c5 3. Nf3  cxd4 4. Nxd4  Nf6 5. Nc3  d6 (117)
    8:  1. e4  c5 2. Nf3  d6 3. Nc3  Nf6 4. d4  cxd4 5. Nxd4  e6 (92)
  
  ```
  
  > **Comments:**
  > **username_3**: Yeah I think I've seen that position a few times. :P I like #7, it starts out with the french defense, lol.  
  
  ---
  
  ### Answer by username_1 on 2013-01-21. Score: 5
  
  I don't think so, because, for example, the french defence can be reached in the following way: `1.Nf3 Nf6 2.Ng1 Ng8 3.Nc3 Nc6 4.Nb1 Nb8 5. e4 e6`. Of course, the knight moves can be repeated more times, with different combinations. Also, `e4` can be delayed with `e3`, when black "wastes" a move with a knight. Thus, it's not too useful to have such a resource.
  
  
  ---
  
  