Sicilian with 2) ...Nc6 and 3) Bb5

Hi,

I am looking for some general guidance about pawn structure.  Against the Sicilian, I usually respond to 2...Nc6 with 3) Bb5.  My plan is to exchange on c6 before black can avoid doubled pawns.  So after 3)....e6 or 3) d6, I exchange, but after 3)...g6 I keep the bishop for a few moves.

My question is.....Is there a general principle about when to play c3 and d4 and when to play b3 and d3.  At first I always tried to play for the big centre with c3.  Then I thought if black plays dc6 I should play for the little centre with b3.  However, in the Carlsen v Radjabov Candidates game in London after 3....e6. 4) Bc6, bc6 Carlsen played 5) b3.

Do these positions need to be learnt on a case by case basis - or is there a general principle ?

Many Thanks

DoubleDum

Thanks for your reply.

I raised this query because of the following game.

Now, white has to decide where to put his pieces.  My plan of d3, b3, Bb2 and Na3-c4 was far less effective than blacks moves of Ne7, d6, 0-0 and f5...followed by h6, g5 and strong play on the kings side.  White pieces look well placed but are doing very little.

Doubledum