kamalakanta: <patzer of patzers: Patzer that I am, 29. h3 is extremely confusing to me. Help?>Hi! I am a patzer myself...especially compared to the grandmasters.
They have a sense of rhythm is their game which is outstanding.
It seems to me that they attack specific problems at a time, one by one, in a sequence.
White came out of the opening with a space advantage, which he was about to turn into a direct attack on Black's King after 20.Bg5.
Black had to weaken his pawn structure to neutralize the direct attack against his King, but was left with a permanent positional disadvantage.
For example, in this game, by move 24 (24.Qf3) we can see that White has a distinct positional advantage: a superior pawn structure. He has two groups of pawns; Black has three.
Also, White's Queen is more active than Black's, and the open file is occupied with his rook.
And White's c-pawn is already on the move.
So White has the advantage. Now, how to convert it?
In the next five moves White's c-pawn advances to c6. If Black had tried to stop this with ...c6, the square d6 would become an invasion point for the White pieces. So Black had to allow this.
Once the pawn reaches c6, a further re-grouping of the White army is in order. 29.h3 takes care of any potential mating threats in the future; it creates breathing space for the White King.
And even though it is a "slow" move, White's advantage is so great, that Black cannot use that tempo to improve his position significantly.
AS the game progresses after this, White's pressure on the c-pawn, and the pressure his rooks exert from the square d7, proves too much for Black to match....
Kamalakanta