I was watching a live chess game. The opening was a Rossolimo, which I always thought was harmless. I was watching white slowly build up his centre and by move 13 he had achieved this. To my surprise, black resigned on move 19! To my eye, at move 13, black was okay, but clearly white disagreed! Even now, after reviwing the game several times, I still don't sense the danger on move 13 (like I would do with other tactics/positional ideas that I am familiar with). I found this game to be really instructive regarding the power of the mobile centre!
Black is already considerably worse by move 13 (although his 13...Na5 is simply losing by force).
17.ef6 is an easy win for White, but 17.Nxe7+ is even stronger. 17.Bh4 also leaves Black in a terrible mess, so it's apparent that Black had simply misplayed his position- it's not a matter of overlooking a tactical shot.
And no, the Rossolimo is not harmless at all- factly it's the most well-respected anti-Sicilian.
Thanks for your input pfren.
Is the Rossolimo as good as the mainline Sicilians for white? It seems more logical to me: instead of "sacrificing" the central d pawn (for black's inferior c pawn) in order to gain activity and a lead in development, white uses black's lack of development (1.c5) to slowly build the classical centre (pawns on e4 and d4). Should I make this my main weapon instead?
If black was worse by move 13, how should he have played the position beforehand?
Instead of developing routinely Black should apply as much pressure as possible against the d4 pawn. So 9...Qb6 or 9...Bg4 are both quite obvious reactions.
9...Qb6 has a dark side: White can offer the dangerous gambit 10.Be3!, so 9...Bg4 is rather the move to be preferred. Now 10.Be3 Bxf3 practically forces white to recapture with the pawn, while 10.d5 Nd4 (or 10...Ne5) is quite comfortable for Black.
White should likely play h3 before committing himself to d2-d4.