## Saturday, January 18, 2014

### King and Pawn endgame improvement

3K4/kp6/p7/1P3p2/8/6P1/7P/8 w - - 0 1

White to move. Is this a win, draw or loss for White? How should White continue?

Oleg Mezjuev said...

1. b6+ (the only move; 1. bxa6 is not good, as black will play 1. ... b5) Kxb6 2. h4 a5 3. h5 a4 4. h6 a3 5. h7 a2 6. h8Q 1-0

Anonymous said...

b6 white wins

Anonymous said...

b6 white wins

Anonymous said...

White wins as follows:
1.b6+ Kxb
2.h4 a5
3.h5 a4
4.h6 a3
5.h7 a2
6.h8=Q

Yancey Ward said...

The key observation is that white can queen the h-pawn in 5 moves and black can queen either the a-pawn or b-pawn in 5 moves, as well. However, if black has to queen the a-pawn, white's new queen on h8 will cover the a1 square, but not the b1 square. White wins by playing b6 with check blocking the b-pawn and forcing black to push the losing a-pawn. If white takes at a6, black will play b5 rather than retake at a6

Yancey Ward said...

I just realized black has a tricky defense. I was just wondering why the f-pawn was in this puzzle since it didn't seem to play any threat since pushing it costs the tempo it gains by forcing white to capture at f4. I then suddenly realized the pawn was there to help hide a stalemate theme. Consider:

1. b6! Kb8!

As I mentioned in my first comment, Kxb6 loses the pawn race since the new white queen will cover the a1 square the half-move before black plays a1Q. However, Kb8 has a point if white is careless:

2. h4! f4
3. gf4! a5
4. h5 a4
5. h6 a3
6. h7 a2
7. h8Q a1Q

And, now, white cannot take at a1 on the next move without stalemating black. The quickest mate is to push the f-pawn at move 4 instead of the h-pawn. White can still mate with the line above by checking from e5 at move 8 and forcing the exchange of queens at e5 or forcing the black king to a8 so that the capture at a1 is with check.

Anonymous said...

The B5 white pawn to A6 first.

Whatever happens after that... won't stop the white pawn on H2 from reaching "queen" status. White for the win! A draw if you mess it up. ;)

My question is... how did black leave the B5 white pawn, all alone for a whole turn? :)

Anonymous said...

b6 wins since white's h pawn queens and controls the a1 square.

Luc Brussels said...

1.b6 Kxb6 2.h4 and black looses a tempo to clear the g file. A promotion on the "a" file doesn't work because the promoted queens are on the same diagonal

s.k.srivastava said...

1b6 wins

Umesh Tawde said...

It is a win for white
1. b6+ Kxb6
2. h5. a5
3. h4. a4
4. h3. a3
5. h2 a2
6. h1Q
And black can not queen on a1 because white queen is on the same diagonal.

Nichlas Demaras said...

b6

Anant said...

b6+ seems to be one way to make black delay pawn promotion by a move, and then march the h pawn to queening. Black can only queen a pawn which can be gobbled up. Seems like a victory for white?

Anand Gautam said...

b6+!! to ensure that Black can only try to Queen the a pawn which gets guarded from h8 :)

1. b6+!! Kxb6 (What else?)
2. h4 1-0

shlosso said...

1.b6+ Kxb6? 2.h4 a5 3.-6.h8Q a1Q 7.Qxa1 is a win for White but Black can play for a self stalemate:
1.b6+ Kb8! 2.h4 f4 3.gxf4 a5 4.-7.h8Q a1Q. This position without wPf4 is a very known study position by David Joseph but now it seems that 8.Qe5+ is an easy win and even 7.h8B should win.
Can Black improve on that?

Anonymous said...

You are right Yancy! In 1...Kb8 variation
After 3. gxf4.a5 4. f5 is faster...a4 5. f6..a3 6. f7..a2 7. f8=Q..a1=Q 8. Ke7#!

Harry

Anonymous said...

the ...2. Kb8-Variation doesn't work, cause white can queen with the f-pawn and then it's mate the next move.