What is the main idea behind the Petroff defense for black?

This gives some info, not sure if it will help : http://en.wikipedia.org/wiki/Petrov's_Defence

thanks forgiven!

Isn't the idea to create a somewhat symmetrical and drawish position to acheive a draw with the Black pieces?

i KillaBeez! I dont look for draw, i want to Win! ;)

Then you shouldn't play the Petroff.  If you want a win, play the Sicilian or an e5 opening that actually gives you winning chances.

so why grandmasters win with petroff and use it often?

Because the Petroff often requires outstanding endgame technique. Therefore, less experienced players can easily be outplayed by skillful grandmasters even if their position is slightly better.

Thanks for your comment Natalia! ..so what opening should i use for great winnig chance if i play black against e4?

 C5 i play pettrof and its very usefull vs big rtg players i beat a 1900 using it

The Petroff is actually considered to be a very sharp opening if played with the intent of producing sharp positions. Most amateurs only think it's drawish because it's often used as a drawing weapon at 2700+ level...

Article just up on the Petrov

I think black's basic idea is the Petroff defence is to trade both central e-pawns, and thus makes it easier to trade heavy pieces and defuse any kingside attack by white.

Installing a strong central Knight on e4 is another major idea, as far as I understand.

 I was just about to say that. Petroff's drawish reputation doesn't come from the actual positions occuring on the board, but from the fact that they have been analyzed to death by the elite.

Petroff lines, on the contrary to their reputation, look completely ming boggling to me, even the sicilian "makes more sense" to my patzerish eyes sometimes. I think OTB you'd have excellent chances of winning right out of the opening if you put in a lot of work into it. On CC, I'm not so sure about that, but it's my main weapon against e5 here anyway.

Thanks!

Also check out the article by Arun and Magesh:

http://www.chess.com/article/view/the-petroff-defense-by-gm-arun-and-gm-magesh

I agree with their conclusion: "If white decides to play for a draw, then Petroff may not be a good opening to try to win, but when White is playing for an advantage, the Petroff has always been a useful weapon as the defensive ideas are always combined with some active ideas when given a chance."

Thanks Atos!

The main idea of the Petroff is to aggressively respond to White's attack on the king pawn by a counterattack on his rather than by passively defending one's own.

To bore your opponent and all of the Chess World thus getting a draw and an early bus ride home. All at minimum effort