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, Anand and Carlsen. 
  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.  
  
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  ## 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.
  
  
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