Answers.Body: <p>This position is discussed in many books, the consensus being that <code>10... a6</code> is the best and most flexible move. As you say, black waits for white to reveal their hand, and <code>a6</code> is generally useful. Play could continue <code>10... a6 11. Be3 Bf5</code> or <code>10... a6 11. Bd2 Rb8</code>.</p>
  
  <p>The move <code>10... Bf5</code> is a serious alternative since it provokes <code>11. e4</code>, blocking the diagonal for white's bishop. In this variation white would ideally like to hold back <code>e4</code> to keep the diagonal open. Still, white can keep an advantage in various ways. Marin in <em>Grandmaster Repertoire 5</em> says that white should try to emulate <a href="http://www.chessgames.com/perl/chessgame?gid=1126709" rel="nofollow">Smyslov-Timman, Moscow 1981</a>.</p>
  
  <p>White often chooses a set-up with <code>Bd2</code>, <code>b3</code> and <code>Rac1</code>, leaving black's <code>Bg7</code> bishop with nothing to attack. In such a position black needs the <code>b5</code> break to create active play. Therefore playing <code>a5</code> is usually not a good idea.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-02-09T19:39:13.480Z
Answers.LastActivityDate: 2014-02-10T09:20:53.520Z
Answers.LastEditDate: 2014-02-10T09:20:53.520Z
Answers.UserDisplayName: Dag Oskar Madsen
Body: <p>I observed that after </p>
  
  <pre><code>[fen ""]
  
  1.c4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 6.g3 Bg7 7.Bg2 O-O 8.O-O Nxd4 9.Qxd4 d6 10.Qd3
  </code></pre>
  
  <p>In many games, Black played the strange move <code>10...a6!?</code> It has been played by top players like <a href="http://www.chessgames.com/perl/chessgame?gid=1070483" rel="nofollow">Kasparov</a>, <a href="http://www.chessgames.com/perl/chessgame?gid=1406073" rel="nofollow">Anand</a> and <a href="http://www.chessgames.com/perl/chessgame?gid=1513055" rel="nofollow">Carlsen</a>. </p>
  
  <p>What is the point of <code>10...a6?</code> Is it a waiting move for White to reveal his hand? It seems like a preparation for a future <code>b5</code>, but why at this particular moment when Black could simply develop the bishop on <code>f5 (10...Bf5)</code>? Also, in some variations, the pawn could be useful on <code>a5</code> so that Black's knight can rest comfortably on <code>c5</code>, so <code>10...a6</code> could be a waste of a move. </p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2014-02-09T03:40:58.397Z
Comments.Text: [Here](http://meta.chess.stackexchange.com/questions/279/tool-used-to-create-chess-analysis-interactive-diagrams-in-many-chess-stack-exch) is the link to the question describing how to create chess diagrams. I think that my answer and response made to the member *RauanSagit*'s comment will be helpful to you. Best regards.
Comments.UserDisplayName: AlwaysLearningNewStuff
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2014-02-09T07:48:15.937Z
Comments.Text: Perhaps Black targets `Qc7` + `Be6` + `Rc8` lineup to pressure `c4` pawn and wishes to protect himself from `Nb5` jump. Also, in some cases Black can play `b5` to open lines which should give him compensation for the sacrificed pawn in view of active piece play. Just a thought... Best regards.
Comments.UserDisplayName: AlwaysLearningNewStuff
Tags: <opening><theory><english-opening>
Title: Why does Black play 10...a6 in the A39 variation of the English opening?
ThreadText: # Why does Black play 10...a6 in the A39 variation of the English opening?
  
  (Asked by: username_0 on 2014-02-09)
  
  I observed that after
  
  ```
  [fen ""]
  
  1.c4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 g6 6.g3 Bg7 7.Bg2 O-O 8.O-O Nxd4 9.Qxd4 d6 10.Qd3
  
  ```
  
  In many games, Black played the strange move `10...a6!?` It has been played by top players like [Kasparov](http://www.chessgames.com/perl/chessgame?gid=1070483), [Anand](http://www.chessgames.com/perl/chessgame?gid=1406073) and [Carlsen](http://www.chessgames.com/perl/chessgame?gid=1513055).
  
  What is the point of `10...a6?` Is it a waiting move for White to reveal his hand? It seems like a preparation for a future `b5`, but why at this particular moment when Black could simply develop the bishop on `f5 (10...Bf5)`? Also, in some variations, the pawn could be useful on `a5` so that Black's knight can rest comfortably on `c5`, so `10...a6` could be a waste of a move.
  
  **Tags:** opening, theory, english-opening
  
  > **Comments:**
  > **username_1**: [Here](http://meta.chess.stackexchange.com/questions/279/tool-used-to-create-chess-analysis-interactive-diagrams-in-many-chess-stack-exch) is the link to the question describing how to create chess diagrams. I think that my answer and response made to the member *RauanSagit*'s comment will be helpful to you. Best regards.  
  > **username_1**: Perhaps Black targets `Qc7` + `Be6` + `Rc8` lineup to pressure `c4` pawn and wishes to protect himself from `Nb5` jump. Also, in some cases Black can play `b5` to open lines which should give him compensation for the sacrificed pawn in view of active piece play. Just a thought... Best regards.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2014-02-09. Score: 5 | Accepted answer
  
  This position is discussed in many books, the consensus being that `10... a6` is the best and most flexible move. As you say, black waits for white to reveal their hand, and `a6` is generally useful. Play could continue `10... a6 11. Be3 Bf5` or `10... a6 11. Bd2 Rb8`.
  
  The move `10... Bf5` is a serious alternative since it provokes `11. e4`, blocking the diagonal for white's bishop. In this variation white would ideally like to hold back `e4` to keep the diagonal open. Still, white can keep an advantage in various ways. Marin in *Grandmaster Repertoire 5* says that white should try to emulate [Smyslov-Timman, Moscow 1981](http://www.chessgames.com/perl/chessgame?gid=1126709).
  
  White often chooses a set-up with `Bd2`, `b3` and `Rac1`, leaving black's `Bg7` bishop with nothing to attack. In such a position black needs the `b5` break to create active play. Therefore playing `a5` is usually not a good idea.
  
  
  ---
  
  