This is one of those pawn endgames where you HAVE TO calculate everything out. It is Black to move. What is the best way for Black proceed? 
Chess Daily News from Susan Polgar
Important pawn endgame
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After 1. dxc5 dxc5,
2. b5!
white king is cut from c file! and can not make progress
Just got back from that Kid Chess Place that you featured a couple of weeks ago. My wife’s first ever chess tournament. (Speed chess.) She had fun and almost won a game. She was ahead in material but lost on time.
Big night for me. Never thought I’d ever get Kathy to play. She had thought that it was a men’s game until I showed her Susan’s blog. We’ve also been watching Susan’s DVD. Thank you, Susan!
As for the puzzle, I think the first move must be to capture that pawn.
1. dxc5 dxc5
2. b5 a5
looks kind of drawish to me.
Jack, I am glad your wife got started in chess. It is a fun game for everyone! Congratulations!
Best wishes,
Susan Polgar
http://www.PolgarChess.com
Anonymous said…
After 1. dxc5 dxc5,
2. b5!
white king is cut from c file! and can not make progress
+++
blunder. my bad …c6 wins in that case.
2. Kc7 is needed. If 2…c6 than 3. a5 wining tempo for black.
Draw
dc5
dc5 bc5
kc5 kc7
kb4 kb6 and black keeps the white king out … maybe
If I were black, I’d take a draw:
1. … dxc5
2. dxc5, bxc5
3. kxc5, a5
4. kb5, kd6
5. kxa5, kc5
… b5 in most lines gets answered by axb5, and black will lose the resulting double b-pawns.
1…dxc5! let’s have a look on other black moves first:
i)1…b5? with the silly idea to win this by a pawn break through
2.c6+ Kd8
3.Kxd6 bxa4
4.c7+ Kc8
5.Kc6 a3
6.d5 a2
7.d6 a1Q
8.d7#
ii)1…bxc5? looks pretty similar to 1…dxc5, but it is not
2.dxc5 dxc5
3.Kxc5 Kc7
4.a5! ( but not 4.Kxb4? Kc6 5.a5 Kd6 6.Kc4 Kc6 7.b4 Kd6 8.b5 axb5+ 9.Kxb5 Kc7=)
4…Kb7
5.Kd6! ( but not 5.Kxb4? Kc6 6.Kc4 Kd6 7.b4 Kc6 transposing into the draw line given above)
5…Kc8
6.Kc6 Kb8
7.Kb6 Ka8
8.Kxa6 Kb8
9.Kb5+-
mainline:
2.dxc5 Kc7!
(but not 2…bxc5? 3.Kxc5 transposing into the line 1…bxc5? given above ii); 2…b5 3.axb5 a5 4.c6++- is even worse)
3.Kc4 Kc6
4.cxb6 Kxb6
5.Kxb4 a5+
6.Kc4 Kc6 with a draw
e.g. 7.b4 axb4 8.Kxb4 Kb6 etc.
greetings
Susan, thank you for this endgame problems, it made me start studying again what I consider my biggest weakness in the game.
What’s wrong with b5 immediately?
After c6+, Kc67, white has to take the b-pawn (can’t let Black do bxa4, bxa4 and b3), so we have axb5,axb5 and White is in Zugwang (or however you spell it) – any King move lets Black take the c6 pawn.
@anonym 10.45
1.b5? c6+
2.Kc7? a5!
3.Kc8/b8/d8 (zugzwang) Kxd6 an white wins at once…
the other b5 refutation is given some posts above
greetings
exc5
ec5,kc7
if c6 kc7 and kxc6
if b6 kb6 =
Vohaul, was it very hard to find Kc7! what a fantastic drawing idea, and appently the only one. i wish i could have found it. i always look foward to your solid anaylsis. keep up the good work!
Kathy
go for it. it only gets to be more fun.
When you start to beat the guys they will do death flips. LOL.
That is where the guy flips off his chair backwards and is declared dead on the chess board.
this is hard susan. but good for me to work on.
after proceding a few calculations, black’s position is lost white move with a5 will ultimately anhilate any hope of promotion for black (observation… black needs 7 moves to promote the pawn if white trade a6xb5, but white will promote with only 6 moves putting an end in black’s game.
– samir