Move 20
 

What strikes me about their move 20.Bg4 is that it obviously pins the knight on d7, and they have an immediate threat of Qa4 winning a piece.

I think 20...Nd4 is possible because if 21.Qa4 f5.

20...Qb7 is an obvious way to get out of the pin. Maybe they're intending to exchange 21.Bxd7 then. They've then captured an important attacker of their b6 pawn and are holding onto this pawn for the time being.

20...Rb7 is possible too but doesn't look so natural to me as 20...Qb7.

Any other possibilities?

20... Qb7 loses a piece to 21.Qa4
20... Rb7 looks drawish
20... Nd5 forces White to commit to one side or the other with the queen

[QUOTE=WMHalsdorf;404120]20... Qb7 loses a piece to 21.Qa4
20... Rb7 looks drawish
20... Nd5 forces White to commit to one side or the other with the queen[/QUOTE]
Yes, 20...Qb7?? indeed does nothing to avert the threat of Qa4. I don't know what I was thinking there.

As I see things at the moment, 20...Rb7 seems an awkward move, putting the rook on a passive square where it no longer defends a8, where it blocks the potential queen sortie to a6, from where it can no longer reach the open a file, and where it is vulnerable to attack if their knight gets to a5.

That leaves 20...Nd4. It's an active move and forces them to commit their queen as you say. Also it enables us to play ...f5 (forces ...f5 actually if they reply 21.Qa4) and thereby avoid the exchange of their bishop for our d7 knight. If we allow the latter, I'm concerned we will end up with no compensation for the pawn deficit.

The only choices I see after 20... Nd5 are
21.Qa4 f5
21.Qd3 f5
21.Qd1 f5
21.Bxd7 Qxd7
Did I miss any?

[QUOTE=WMHalsdorf;404297]The only choices I see after 20... Nd5 are
21.Qa4 f5
21.Qd3 f5
21.Qd1 f5
21.Bxd7 Qxd7
Did I miss any?[/QUOTE]
They have no other moves as far as I can see after 20...Nd4. But 21.Bxd7 seems to blunder material because of 21...Nxc2 22.Bxc8 Nxa1, and if they play 21.Qd1 or 21.Qd3 we should consider carefully whether we want to reply 21...f5 (though the move is forced after 21.Qa4). Preventing Bxd7 is one thing, but allowing them to open our g file against our king with 22.exf5 at a moment when their queen has quick access to the kingside could be dangerous.

At the moment my preferred move is still 20...Nd4.

[QUOTE=Brian-E;404326]They have no other moves as far as I can see after 20...Nd4. But 21.Bxd7 seems to blunder material because of 21...Nxc2 22.Bxc8 Nxa1, and if they play 21.Qd1 or 21.Qd3 we should consider carefully whether we want to reply 21...f5 (though the move is forced after 21.Qa4). Preventing Bxd7 is one thing, but allowing them to open our g file against our king with 22.exf5 at a moment when their queen has quick access to the kingside could be dangerous.

At the moment my preferred move is still 20...Nd4.[/QUOTE]

21.Bxd7 Nxc2 22.Bxc8 Nxa1 23.Rxa1 and there is no way to tamke the bishop on c8 because of the pawn moves to b7 making us down a knight.

[QUOTE=WMHalsdorf;404336]21.Bxd7 Nxc2 22.Bxc8 Nxa1 23.Rxa1 and there is no way to tamke the bishop on c8 because of the pawn moves to b7 making us down a knight.[/QUOTE]
That's true. I was wrong.
Still, we have a fine position after 20...Nd4 21.Bxd7 Qxd7 (as you indicated before) 22.Q moves Qb5 with various threats against b2, c4 and a6. So 21.Bxd7 doesn't look like a good reply for them anyway.

What is your preferred move for us at the moment, WMH and davar55?

I'm going to have another look at Rb7 to see if I missed something, otherwise its Nd4

[QUOTE=WMHalsdorf;404387]I'm going to have another look at Rb7 to see if I missed something, otherwise its Nd4[/QUOTE]
If you (or davar55) spot anything new we need to hear about it urgently because otherwise there won't be time to discuss it. We have just over 24 hours.

I didn't find anything new. Will post 20... Nd4 latter in the day in case davar55 finds something.

[QUOTE=WMHalsdorf;404494]I didn't find anything new. Will post 20... Nd4 latter in the day in case davar55 finds something.[/QUOTE]
OK :tu: