Sunday, December 13, 2009

Pawn endings are hard (part 2)

White to move
Bill Brock - Andrew Taylor, MCA FIDE, 6 Dec. 2009

Please consider the following notes provisional: I'm still not quite sure what's going on in this ending.

Every pawn ending starts as something else: in this case, a bishop ending.  In the diagrammed position, I thought I was slightly better despite the doubled f-pawns because the e5 pawn restricts the Black bishop's scope.  I should have been more worried about my kingside pawn structure.  My f2 pawn is on a dark square and part of a doubleton.

27. Kb4?! 
27. Be3 is equal
27... Bf8+ 28. Ka5
Is this king penetrating towards victory? Or is it hopelessly offsides?
28. Bc5 29. Be3 

After 29.Be3: Black to move

The pawn ending is not yet winning.  29... Bxe3 30. fxe3 g5 31.
Ka6?? h5 32. Kxa7 f5! 33. exf5 e4 34. fxe4 g4 35. f6 Kd7 is an easy win for Black.  But 31.Kb4! holds the draw.

30. Ka6??
I should have sacrificed a pawn to stay in the bishop ending with 30. Bg5!?
30... f5?
Black breaks through with 30... Bxe3!! 31. fxe3 g5 32. b4 h5 33. Kxa7

Analysis position: Black to move after 33. Kxa7
33...f5! is a beautiful breakthrough combination: if White takes the f pawn, then 34...e4! deflects the f3 pawn, after which the g5 pawn runs free.

31. exf5 gxf5 

After 31...gxf5: White to move
32. f4!
And somehow it's a draw again....
31... Bxe3 33. fxe3 exf4 34. exf4 b4!
I completely overlooked this strong and natural move (the b4 pawn paralyzes both a2 and b3).

White to move: 
there is nothing in the Rules of Chess that expressly prohibits counting on one's fingers
35. Ka5??
The only move is 35. Kxa7!: I simply did not believe that this move could possibly draw (it seems so time-consuming to grab a7, then run back to grab b4), but the a2 pawn runs quickly, and the Black king has to make a clearance move for the f5 pawn. 35... Kd5 36. Kb6 Ke4 37. Kc5 Kxf4 38. Kxb4 Kg3 39. a4 f4 40. a5 f3 41. a6 f2 42. a7 f1=Q 43. a8=Q

Analysis position: Black to play (looks like a draw)

Back to the game

35... Kc5 36. Ka4 h5 37. h4 Kd4 38. Kxb4 Ke4 39. Kc3 Kxf4 40. Kd2 Kf3! 41. b4 f4 0-1

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