<21.?>

Target: 0:40;000
Taken: 0:08;386

Material: =

Candidates: <[Qxe8†]>

-ML-
<Once> words really well what makes this position extremely troublesome for Black, his Pg6. Black would have been pretty equal off with 20....Bg7, as White would rather not take the a6 pawn, however, as materialistic Black was playing already, 20....a5 is not an unexpected move, something White thought as well.

<21.Qxe8†!> utilizes the overworked Black Queen into a multiple-theme combo winning at least a Rook. 21....Nf8 wins another piece after 22.Nxf6† at the least, whereas 21....Kg7 22.Qxd8 Rxd8 23.Nxf6 Kxf6 24.e5† creates a very unfavorable position for Black and still a Rook down, Black might as well resign or go with:

1. Bishop and rook both guarded only by the Q.

2. Bishop and rook both under attack.

Here's a little idea for you to consider:

Make a game collection called "Instructive posts by Once" (or something like that), and when you make a post that is instructive beyond the game at hand, add that game to this collection.

Why, thank you for putting me straight. I'm going to rush out now and practise that really tricky alphabet and number thing.

And a double thank you for thinking up such a caring, polite and sympathetic way to point out my error.

<The Story>
The queen pulls at her flowing white garment as her armor-bearer, Strand, pulls the final strap on the back plate. Strand spoke "Madam, are you ready for the task the King has given you?" The Queen, Whitney, takes her sword and sheath and straps it to her waist. "Strand, I must do as my king says. The white landscape about them, known as Queens Rook, blows leaves off the trees in the rustling night. Yet it was the most solemn night for Whitney and Strand. Then Strand spoke again "Queen, we must go quickly.""Yes, let us leave." As the quickly mounted their steeds, the queens heart was troubled.

The humble knight Klaus was holding the reins of his horse tightly as he felt his throat constrict. He said to him self, "The time is coming, soon, soon, soon." His son came from the tent and spoke "Father, what is the matter?" "John, rest, for your cousin is coming to take you back so you will be safe." John strode back to the tent and quickly fell asleep. The night grew colder by feeling and temperature to Klaus, and he felt the weight of his job on his shoulder. Klaus thought "I should of not put my son in danger."

The Black king paced nervously in his study, when the door burst open with Daniel in the way, The King said, "What is it Daniel, these are urgent times!" Daniel said,"Sir, something is stirring.""I know."

As the final operation approaches the Queen destroys the tower right before she is struck and breathes her last knowing she has done good for the White Kingdom...

Klaus and his company jumps in to action upon seeing the signal and rushes to the the Black territory of King's Bishop....

After 20 Qa4 Bg7 what next? Playing against Crafty End Game Trainer, I really struggled to find anything at all for White:

click for larger view

Crafty link to the pre-puzzle position: http://www.chessvideos.tv/endgame-t...

I tried various alternative plans none of which worked and all of which allowed Black to escape with at least an equal position. Finally I gave up and input the position into Crafty with colours reversed. Crafty recommends as best for both sides 21.f4 Kh8 22.e5 Ra8 23.Qc6 b5 24.Rf1 Qc8 25.Rd2 Rd8 26.c4 dxe5 27.Ne7 Qb8 28.Rxd8+ Qxd8 and after further obscure complications White wins a Pawn in an ending that is eventually drawn.

21 f4! is positionally correct but somehow hard to see - the Pawn is on the same colour square as the Bishop, counter-intuitive, but increases White's Black square grip. It is interesting that 20 Nxf6 seems NOT to be the best move - the black Q gets right back in to the game and the weak Black squares cannot be exploited. The threat now is 22 e5. It is most interesting that Crafty defends with 21...Kh8 - again a move that is wholly counter-intuitive (to me) but guards aginst N check tactics.

The only reason I can see for 20...a5(+5.74) is to stop the Queen snipping up a6. Alternatives:-

Analysis by Rybka 3 1-cpu: depth 17:

1. (0.54): 20...Bg7 21.Qc6 a5 22.Rf1 Nc5 23.Bxc5 bxc5 24.c3 Re6 25.g3 Bh8 26.Kg2 Qe8 27.Qxe8+ Rexe8 28.Rh1 Be5

2. (0.62): 20...Bh8 21.g3 Bg7 22.Qc6 a5 23.Re2 Nc5 24.Bxc5 bxc5 25.Kg2 Re6 26.c3 Qe8 27.Qxe8+ Rexe8 28.Kf2

3. (0.81): 20...Be5 21.f4 Bh8 22.Qxa6 Ra8 23.Qc4 Rxa2 24.f5 Nc5 25.b4 Ra4 26.f6 c6 27.Ne7+ Rxe7 28.fxe7 Qxe7 29.Bd4 b5 30.Qc3 Bxd4+ 31.Qxd4 Nb7 32.c3

4. (1.06): 20...b5 21.Qxa6 Bg7 22.Qc6 Ra8 23.Qxb5 Rxa2 24.Qc4 Qh4 25.b4 Ra3 26.g3 Qh5 27.Qc6 Rb8 28.Kg2

5. (1.19): 20...Rf8 21.f4 Bg7 22.Qxa6 Re8 23.Qc4 c5 24.a4 Rb8 25.g3

My thinking - possibly flawed - went something like this:

White has several plans to try. He can go caveman style for the h or f file hack. He can aim to plug the black queenside with Qc6. He has space to double his rooks on the d or e file. His knight is beautifully placed and if black ever does play c6 we get some pressure against the d6 pawn. The Be3 has useful potential on either wing - the standard anti-dragon tactic of Qd2 and Bh6 might even be possible.

Black, on the other hand, doesn't have so many options. He can't double on the d and e files because e7 and d7 are mined by the white knight and queen. The Bg7 isn't doing anything useful and the knight doesn't have many useful squares to jump to. What's more I can't see any obvious pawn breaks for black. f5 looks exceedingly dodgy.

So white doesn't have a forced win or even a strong attack, but (to me at least) he seems more comfortable in this position. He has better pieces, and more chances to improve his position.