Correct: the knight is worth a deal more than the bishop right now. It can't easily be shifted from the d5-square, neither: 20.c4?? would leave the d-pawn backward and weak for the rest of its short life.

White should just get rid of the weak d-pawn with 22.d4. Black has nothing better than 22...cxd4 (22...Qc2 23.Re2 and white gains a tempo to double the rooks)

Yes: after 22.d4 (this seems to be the right time for it!0 22...cxd4 23.Bxd4 and the bishop isn't so badly placed either.

23.d4 is still playable.

Finally!

In these kinds of positions where every piece is contesting for the center, the player who breaks the tension usually ends up worse. 24...Qf5 is a useful waiting move here.

of course white can whip up some tactics of her own with 26.Qg4!

I think I'd just play 26.Re2. After 26.Qg4 g6 it's I find it hard to find a follow-up. But Black might have made a slight error with his knight move. It would have been fine had White's d1-Rook still stood on a1. See next...

27.Qe5! Active defense is the best defense!

Yep: 27.Qe5 and White seizes the initiative with advantage. To wrench it back again, Black just about has to sac on d4: 27.Qe5! Rxd4! 28.Rxd4 Rxd4 29.Qxd4 Nd3! At this point, Black's counterplay might well be good enough to hang on (White has to play 30.Ra1, by the look of things).

Of course you mean d4 instead of b4 (except for the first one)...

Better was Red1 methinx.

l-d-j yes d4, thanks for spotting it :*

Wonder why white didn't opt to play Rd1.

29.Rd1 Nxd4, everything trades off anyway. I guess white wanted to keep the 3:2 majority on the Q-side (if everything trades off on d4, white ends up with an isolated d-pawn, which is not as good as the 3:2).

With an isolated d-pawn, White would be at a slight disadvantage, but, with care, ought to survive the major piece ending. She would have to judge, though, whether it were better to keep a pair of rooks on as well as the Queens, or make it a 'pure' Queen and pawn ending: [[[Q+P ending]]]: 29.Red1 Nxd4 30.Rxd4 Rxd4 31.Rxd4 Rxd4 32.cxd4 g5! 33.Qd2 gxf5 34.gxf5. This line leaves Black with a positional advantage of the stronger pawn structure. [[[Rooks on]]]: 29.Red1 Nxd4 30.Rxd4 Rxd4 31.cxd4 ... A although Black's pawn structure is the stronger yet, White's only real weakness (apart from the light squares) is the isolated d-pawn. Black would have to play some tall chess to win this ending.

I'd try 30...h5, looking to break up white's K-side.

I'm beginning to wonder if Joanne is playing for the win. With 32.fxe5 she could draw fairly comfortably after 32...Nxe5 [a] 33.Bxh6! or simply [b] 33.Qxe5 Rxd2 33.Re2 Rd1ch 34.Re1. Trickier, though, is 32...Re8, when 33.Qb5 Qe6 keeps the battle raging. Not sure how White should proceed after that. Maybe 34.Kg2 - prevaricating. Not 34.c4?? Nd4! and Black is on the way to winning.