Answers.Body: <p><strong>Edit:</strong> Using the <a href="http://www.chessgames.com/perl/explorer?node=1928652&amp;move=4&amp;moves=e4.e5.Nf3.Nf6.Nc3.Bb4&amp;nodes=21720.21721.21722.24467.24468.1928652" rel="nofollow">chessgames Opening Explorer</a>, I confirmed the move is playable, here is the list of possible replays:</p>
  
  <pre><code>Move     #games
  ---------------
  4.Nxe5   175
  4.Bc4    151
  4.d3     52
  4.a3     14
  4.Nd5    12 &lt;- my option
  4.Be2    2
  4.d4     2
  4.Bd3    1
  4.g3     1
  </code></pre>
  
  <p><strong>4.Nd5</strong> looks viable and easily prevents that double pawn.</p>
  
  <p>It also pushes the game into an aggressive one, which can be good or bad depending on your play-style.</p>
  
  <p>Final position after <strong>4.Nd5</strong>:</p>
  
  <pre><code>rnbqk2r/pppp1ppp/5n2/3Np3/1b2P3/5N2/PPPP1PPP/R1BQKB1R b KQkq - 5 4
  </code></pre>
  
  <p>He will most likely do NxN, I don't see many other choices here as both the Bishop and the e Pawn are attacked:</p>
  
  <ul>
  <li>4...Nxd5</li>
  <li>4...Bd6 (weak move)</li>
  <li>4...a5 (weak move)</li>
  </ul>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-12-11T20:54:09.517Z
Answers.Text: But after 4.Nd5 Nxd5 5.exd5 White stills ends up with a doubled pawn, right? (Not that this is terrible, just that the OP wants to avoid it.)
Answers.UserDisplayName: TKR
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-12-10T19:37:19.707Z
Answers.LastActivityDate: 2013-12-10T19:54:26.843Z
Answers.LastEditDate: 2013-12-10T19:54:26.843Z
Answers.UserDisplayName: ajax333221
Answers.Body: <p>I will be brief with the answer, ask for further clarifications/advices if you need them:</p>
  
  <p>The opening is called <strong><em>Petroff's defense</em></strong>, but you have played a sideline in your game.</p>
  
  <p>The <strong><em>ECO code</em></strong> of the opening is <strong><em>C42</em></strong>.</p>
  
  <p>It usually goes like one of these two:</p>
  
  <ol>
  <li>e4 e5</li>
  <li>Nf3 Nf6</li>
  </ol>
  
  <p>And now first line is: 3. Nxe5<br>
  Second one is : 3. d4</p>
  
  <p>Your move is a sideline, I have never played it before, but you can look it up, it is not necessarily bad.</p>
  
  <p>Hopefully this helps.</p>
  
  <p>Good luck.</p>
  
  <p>Best regards.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-12-10T17:56:53.907Z
Answers.LastActivityDate: 2013-12-10T17:56:53.907Z
Answers.UserDisplayName: AlwaysLearningNewStuff
Answers.Body: <p><code>4. a3</code> should be a good move. It's like a reverse Ruy Lopez with an extra tempo.</p>
  
  <p>You can look it up in any opening database. Here's one (free): <a href="http://www.shredderchess.com/online-chess/online-databases/opening-database.html" rel="nofollow">http://www.shredderchess.com/online-chess/online-databases/opening-database.html</a></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-12-10T18:07:37.083Z
Answers.LastActivityDate: 2013-12-10T18:07:37.083Z
Answers.UserDisplayName: Sunny
Answers.Body: <p>Best line is 3. Nxe5.</p>
  
  <p>If you insist on 3. Nf3 Nf6, best is 4. Bb5 (Four Knights: Spanish Variation).</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-12-22T23:41:35.953Z
Answers.LastActivityDate: 2013-12-22T23:41:35.953Z
Answers.UserDisplayName: Geoffrey Hale
Body: <p>I am new to chess and am confused on what to do with the following opening</p>
  
  <pre><code>[fen ""]
  
  1. e4 e5
  2. Nf3 Nf6
  3. Nc3 Bb4
  </code></pre>
  
  <p>I have been playing <code>4. a3</code>, but the Bishop then proceeds to take c3 so I end up with a doubled pawn.</p>
  
  <p>If someone could offer some guidance or tell me what this opening is called so I can do some research, it would be very much appreciated.</p>
  
  <p>Cheers</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-12-10T16:31:33.720Z
Comments.Text: So you end up with a doubled pawn. Life goes on. You can't play chess without allowing your pawns to get doubled sometimes.
Comments.UserDisplayName: dfan
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-12-10T17:40:35.650Z
Comments.Text: ^Exactly. Plus, doubled pawns aren't always as bad as they're made out to be. The only time they can be called bad is when they're doubled and isolated, or stops a pawn majority's ability to create a passed pawn in an endgame (if it could've otherwise)
Comments.UserDisplayName: Sunny
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2013-12-23T15:15:02.430Z
Comments.Text: A doubled pawn means you have an expressway for your rooks.  The art is arranging it so the opponent is weak on that file.
Comments.UserDisplayName: Tony Ennis
Tags: <opening>
Title: Opening assistance for a beginner
ThreadText: # Opening assistance for a beginner
  
  (Asked by: username_0 on 2013-12-10)
  
  I am new to chess and am confused on what to do with the following opening
  [fen ""]
  
  1. e4 e5
  2. Nf3 Nf6
  3. Nc3 Bb4
  
  I have been playing 4. a3, but the Bishop then proceeds to take c3 so I end up with a doubled pawn.
  If someone could offer some guidance or tell me what this opening is called so I can do some research, it would be very much appreciated.
  Cheers
  
  **Tags:** opening
  
  > **Comments:**
  > **username_1**: So you end up with a doubled pawn. Life goes on. You can't play chess without allowing your pawns to get doubled sometimes.  
  > **username_2**: ^Exactly. Plus, doubled pawns aren't always as bad as they're made out to be. The only time they can be called bad is when they're doubled and isolated, or stops a pawn majority's ability to create a passed pawn in an endgame (if it could've otherwise)  
  > **username_3**: A doubled pawn means you have an expressway for your rooks.  The art is arranging it so the opponent is weak on that file.  
  
  ---
  
  ## 4 answers
  
  ### Answer by username_4 on 2013-12-10. Score: 4
  
  Edit: Using the chessgames Opening Explorer, I confirmed the move is playable, here is the list of possible replays:
  Move     #games
  ---------------
  4.Nxe5   175
  4.Bc4    151
  4.d3     52
  4.a3     14
  4.Nd5    12 <- my option
  4.Be2    2
  4.d4     2
  4.Bd3    1
  4.g3     1
  
  4.Nd5 looks viable and easily prevents that double pawn.
  It also pushes the game into an aggressive one, which can be good or bad depending on your play-style.
  Final position after 4.Nd5:
  rnbqk2r/pppp1ppp/5n2/3Np3/1b2P3/5N2/PPPP1PPP/R1BQKB1R b KQkq - 5 4
  
  He will most likely do NxN, I don't see many other choices here as both the Bishop and the e Pawn are attacked:
  
  4...Nxd5
  4...Bd6 (weak move)
  4...a5 (weak move)
  
  > **Comments:**
  > **username_5**: But after 4.Nd5 Nxd5 5.exd5 White stills ends up with a doubled pawn, right? (Not that this is terrible, just that the OP wants to avoid it.)  
  
  ---
  
  ### Answer by username_6 on 2013-12-10. Score: 2
  
  I will be brief with the answer, ask for further clarifications/advices if you need them:
  
  The opening is called ***Petroff's defense***, but you have played a sideline in your game.
  
  The ***ECO code*** of the opening is ***C42***.
  
  It usually goes like one of these two:
  
  1. e4 e5
  2. Nf3 Nf6
  
  And now first line is: 3. Nxe5  
  Second one is : 3. d4
  
  Your move is a sideline, I have never played it before, but you can look it up, it is not necessarily bad.
  
  Hopefully this helps.
  
  Good luck.
  
  Best regards.
  
  
  ---
  
  ### Answer by username_2 on 2013-12-10. Score: 1
  
  `4. a3` should be a good move. It's like a reverse Ruy Lopez with an extra tempo.
  
  You can look it up in any opening database. Here's one (free): <http://www.shredderchess.com/online-chess/online-databases/opening-database.html>
  
  
  ---
  
  ### Answer by username_7 on 2013-12-22. Score: 0
  
  Best line is 3. Nxe5.
  
  If you insist on 3. Nf3 Nf6, best is 4. Bb5 (Four Knights: Spanish Variation).
  
  
  ---
  
  