I was thinking ...Nh7. But clearly Black is interested in freeing his f-pawn. Looking at this position reminds me of the sort of games GM Tigran Petrosian used to play.

yes, I used to have a book of Tigran Petrosian's best games, and that sort of play was in one of his games.

Isn't preparing f5 a little slow as black's cramped pieces can't regroup fast enough to attack the White kingside even if a pawn storm there opens a file? Why not Play on the queenside with rc8, a5, then opening the c file and undermining the overextended pawn chain with b5?

White is aiming at nothing on the Qside, and wants to attack on the Kside. I would have preferred Nh7 too, but this move is flexible: the N can redeployto c7 and play for the queenside. This move is worse than Nh7 if white decides to counter with g4, but this is not likely to happen, so the move seems ok to me.

Is it preparing some tactics on e5 for later on (sacking a piece for two pawns and making the d pawn past?)? If not, isn't the fianchettoed Bishop just looking at granite?

f4's break will be part of white's plan if black keeps so passive for long.

I really was expecting ...f5 hereabouts.

Very interesting again. Two games in a row that show a divergence about the flack on which the attack has to be performed. I like f5 here...

Nice freeing move... Opens the battle the the center with the constant threat of attacking the White kingside with pawns. But I think it's important to not improve his Bishop with a premature e4 (after bc2 or qe2)

It was wiser to wait to the Bd3 move before to play this one. Now it wins a tempo but for the next...

I am very curious about to know what were both player's thoughts about this "war for e4". Black is winning now (black CAN play d4).

It does look to me as though Black might be mixing plans, which doesn't usually go well. I thought ...e4 (anyway) or ...g6 might be worth thinking about.

It has to be said that e4 at once allows Nd4, and this threatens inmediately the f4 pawn. g6 would be required (?).

Now, e4 allows f3, and black is not ready to place a supported R on 8 - unless something weird like Qf8 is played. Still, black's answer looks too passive: now the f4 pawn is pinned and g6 is undefended. Black's attack is not easy.

Woo. This is looking uncomfortable for Black, now.

A pity the players have not sent about this move: was it forseen? Was it a surprise? Who calculated until when?

Black is playing at: "do you want to open the g file? Very well, do it! It will be in my favour."

This serves a defensive function as well, of course, blocking the g-file.

Because rg1, qh5, etc are looming, the black king could easily come under attack (and if the position opens and the two white Bishops come to bear in conjunction with a rook on the g file, black is dead)

A r on g1 was very dangerous for black.

The B can be diverted at any time by the sacrifice of the h3 pawn: h4, Bxh4, and the column is white's. Nf3 seems the most dangerous move for black.

Queen h5 and then h4 seems quite promising for White as the rook has to protect f5 and can't leave the f file to defend against h4 and the subsequent powerful attack in the g file.

I think white must think about undermine black's kingside. Nf3 allows h4, the freedom of the g column.

This also prepares the very venemous b4 from White which if black takes leads to white activating his queen with tempo and if not allows white to come crashing through with c4-c5. The black d pawn could not take because of d6 forking his pieces, and if black ignores that, White can choose between creating a covered past pawn with c6 or exchanging on d6 and piling up on the now weak e5 pawn.