Post Sun Jun 10, 2012 9:35 am

Chess Opening - The Main Ideas?

[Event "ChessCube Game"]
[Site "www.chesscube.com"]
[Date "2012.06.10"]
[Round "-"]
[White "[email protected]"]
[Black "[email protected]"]
[Result "0-1"]
[WhiteElo "1400"]
[BlackElo "1405"]
[Time "01:14:06"]
[TimeControl "900"]

1. e4 e5 2. Nc3 Nf6 3. f4 d6 4. fxe5 dxe5 5. Nf3 Nc6 6. Bc4 Bb4 7. Ng5 O-O 8. d3 Bg4 9. Qd2 Nd4 10. a3 Bxc3 11. Qxc3 h6 12. h3 hxg5 13. hxg4 Nxg4 14. Bd2 b5 15. Bd5 c6 16. Bxc6 Rc8 17. O-O-O Rxc6 18. Qb4 Nxc2 19. Qb3 Nd4+ 0-1

In this game, the opening turned out to be the "vienna" (so says the ChessCube UI, anyway) opening. I don't know openings by heart or anything, but I was wondering about the main ideas beyond "development". Let's say that white plays e4, I play e5, and we get to his Nc3 move. What if, instead of Nf6, I had done something like playing a6? I don't think that there's any name ChessCube would give an a6 move response (like, Vienna Falkbeer Variation or some such).

So after this move, since there's no "main line", as it were, to follow - what are the main ideas? Should I be developing my pieces and castling? How about controlling space? When do I know to do what?

Thanks for reading!