Originally posted by tvochess
Thanks for posting this game and the analysis. Well done.
What do you think went wrong for Black? My guess is 16. .. c5, allowing 17. d5 so that black forever loses control of c4.
After Black allows 22.a5 he has practically no plan and he must only defend.With 2 weak pawns(a6 and d6) , and the lack of space , defending on k-side proved an impossible task for him.Black was in a positional zugzwang with no counterplay or any chance to improve his position.
Seems it was an evaluation mistake from Carouana who didn't play 21....a5(to prevent 22.a5) because of the additional weakness on b5 ( which though was much prefferable than the weak a6 pawn) or because he believed he could hold the position.
White remains better but Black has much more easy defense because there is a clear defensive plan ...Nd7-Nb6.If white decides to exploit b5-weakness with Nc4-Na3-Nb5 Black's position is again much better( in comparison with the game) and the attack on k-side much easier to be dealt with.
It is a very instructive game on how important pawn structure is and how one well placed piece can leave the opponent literally crippled.