The game has developed into a kind of Leningrad Dutch Defence. I wonder if the appellation "Leningrad" is still appropriate?

this is certainly of the leningrad ilk, i play this defence religiously to 1. d4.

i am of the understanding this move is to prepare for Qe8, preventing Nb5, threatening the queen/rook fork, and forcing black to move his queen back or his knight onto the side. for me a very important move, as i like my QS knight to be active.

The absence of queens seems likely to depreciate Black's K-side action without necessarily compromising White's chances on the other wing or in the centre. It's hard to say who got the better deal out of the exchange.

i agree, i would never seek to trade off queens here, personally i'd have moved the king onto h8 as soon as the queen comes onto that diagonal.

A manoeuvring phase: Black is a little congested at the moment, so has to be careful. It will be interesting to see what she has in mind for the f8-knight. It could have gone to f6, but maybe she felt it was too risky...

Now we have a very unusual game indeed: all 8 minor pieces, all present and correct, and not a single major piece in sight. This will be interesting!

Could White have defended the pawn? Instead of 24.a4, the only attempt that i can see is 24.b5 with a view to hold the pawn by 25.Ba3. But 24...c5 cuts that defence off.

Black has a great position, here: very centralised, yet applying pressure right across the board.... No wonder Black has the wood in the coming clash.

The situation calls for some fine calculation here - it's all a bit more complicated than it looks. What would have happened if White had just recaptured on g3? A] 31.hxg3 Nxe5 32.Nfxe5 (32.Ndxe5 Bxb4 33.Nd4 Bd5) 32...Nc3 33.a5 a6 after which, Black has only the one pawn extra, but the bishop pair on an open board: a big edge. B] The other pawn capture would meet much the same response. C] 31.Bxg3 Nxg3 32.hxg3 Nb6 33.a5 Nd5 ... and something will have to give on the Q-side.

Two pawns extra, a majority on both wings, pieces all centralised. Napoleon would certainly approve.

The right approach. It's in Black's interest to force piece exchanges when she can. It is difficult to find any kind of plan for White 2 pawns down. A remote possibility is to hope for an endgame in whilch Black is left with an a-pawn and LSB against White's lone king standing near a1. But how do you steer for that? Black has the initiative.

Bad luck. The king had no way forward, and f2 seemed to offer the only avenue by which he could approach the centre. It's not often you see such an effective restraint so late in the game in such an open position. Probably White had to try 42.h4, which would have forced a pair of pawns off. As it left Black with a passer on that side of the board, it would have been hard to contemplate. Note that 42.Bd2 was hopeless, as 42...Be3 at once forced off the bishops. The knight and pawn ending would have been hopeless for White.

Black is taking no chances ... and giving no chances. White has absolutely no play, nor is Black going to give him any.