Sunday, August 12, 2007

Pawn Races II

Nimzowitsch-Tarrash, San Sebastian 1911

Black to move. Black has an outside passed pawn (a-pawn). While the White king rushes to the a-file to stop it, Black eliminates White's g-pawn. Now the race is on--it's Black's f-pawn vs. White's h-pawn. Both sides queen and draw.

But Tarrasch saw something much, much better: 1...a5 2.Ke4 f5+! 0-1.

White has no good moves. If 3.Kxf5, the a-pawn queens. If 3.Kd3 f4! and White's kingside pawns aren't allowed to connect and will be easy prey for the Black king. What a brilliant tactic--it's called "pawn dislocation".

Pelling-Miles, Ilford 1974

Black to move. Without any pawn moves, it's a draw. Black moves Ke4, Kf3, Kg2, Kxh2, Kxh3. White moves Ke7, Kxf7, Kxg6, Kxh6, Kg5. (Notice I look at Black's and White's moves independently--this is a fast and accurate way to calculate when the kings are moving independently of one another).

But consider 1...g5. If 2.fxg5 hxg5 and Black can begin racing his e-pawn right away. If 2.f5 e5 and Black will win the race. If White doesn't make a pawn move at all then 2...gxf4 3.gxf4 f5 and Black's f-pawn will promote.

In actual play, I ran across this variation: 1...g5 2.fxg5 hxg5 3.h4?! gxh4 4. gxh4 Black to move. What now?

Continuing the race loses! You must reappraise a pawn ending every time you see an unexpected move. Black wins with accurate play. He's in the square of White's passer so he can capture it. Black's connected passers are untouchable, because if White attacks the back-pawn, the front-pawn promotes.

4...Ke4! 5.h5 Kf5! 6.h6 Kg6 7.h7 Kxh7 -/+.

Grigoriev, 1933

This one comes from my favorite composer. It's obvious the immediate race only draws. In 5 tempos White queens, but in 4 tempos Black's pawn is in the perfect position to draw the resulting Queen vs Pawn ending.

We can use the "Rule of Exclusion". Since b4 draws for certain, and Kf6 (getting into the square of the h-pawn) doesn't lose, play it immediately. One trick to pawn endings is knowing when not to calculate!

1.Kf6! h5 2.Kg5! Kg2

Now Black is one tempo closer to queening, and is threatening to get inside the square of our pawn, so advancing our pawn makes sense.

3.b4! Kg3 4.b5! h4 5.b6! h3 6.b7! h2 7.b8=Q!

Now it's Queen vs Pawn. Against a rook pawn, these positions are usually drawn, so we must calculate very carefully in order to win.

8.Qb2+ Kg3 9.Qc3+ Kg2 10.Qd2+ Kg3 11.Qe3+ kg2

Our Queen has approached. Now it's time for our king to approach, but again we must calculate the next few move very carefully.

12.Kg4 h1=Q 13.Qe2+ Kg1 14.Kg3 Qh4+ 15.Kxh4 +/-


Anonymous said...

Beautiful stuff....I think you will become a master. I'm an IM and was quite impressed by your thorough approach...rubyxx

likesforests said...

Wow... thank you rubyxx.