If black is contemplating b5, that rook would have been more mobile on the b file.

This manoeuvre has been on the cards for quite some time now. The question is, does it want to be in front of the f-pawn, or behind it? If the latter, then Rf1 should follow shortly.

...b5 is coming...

In front, then.

Which f6 easily counters, but sticks the black queen on the 7th rank.

Black's K-side is looking very porous!

One of Napoleon's dictums was never to inhibit your opponent from making a mistake. Black would scarcely have dared to play ...g5 in response to any alternative move White might have chosen to play. I probably would have been inclined towards 23.Qh4, but continuing the knight's journey 23.Nf1 would have been equally strong. But what all this shows is that Black is extremely vulnerable on the light squares. If there were no lock on the White bishop, Black would be much worse off than he already is.

Practically forced. But now what?

But this manoeuvre has cost White a tempo.

Instead of this move, Black might have got himself some counter-play by 24...f5! with the idea 25.exf5 e4 26.Re1 Re5 27.Ng4 Rexf5 with further tactics to come that peg back White's material lead. White would probably still have a winning game, but Black would have the wherewithal to put up a decent show.

White has to be quite circumspect hereabouts. There is a slight chance of the queen getting itself trapped.

One has a vague feeling that, the light squares wanting defences, the bishop ought to have been kept on the board, whatever the knight's menace.

But 27.Qxg4 might have induced the weakening 27...g5. Certainly it would more securely have nailed down at least one of Black's remaining pieces. And that would be very much in White's interest.

(??) Oops... Now 28... h5! will be very embarrassing for White...

Black missed a fine chance to equalise the game: 28...h5! 29.Re3(best) g5! 30.Qg3 hxg4 etc. White would have lost the exchange, but might have maintained enough attack to hold out for a draw.

Whither is this rook bound? If he wanted to conjure up play on the Q-side maybe ...Rb8 was to be preferred.

OK, but maybe it could have waited upon 30.f5, to nail down the K-side. But Black isn't going to take on f4, is he?