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Date: 10 Aug 2006 03:58:04
From: [email protected]
Subject: Can White draw this pawn endgame?
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With best play, can White draw this endgame against Black?
FEN: 5k2/2p2ppp/1p2p3/3pP3/8/2P1P3/5PPP/6K1 b - - 0 25
Diagram: http://tinyurl.com/mkpfb
I think no. Black should create a passed pawn on the queenside, while
his king gobbles up pawns on the kingside. White can only stop one of
these two threats.
In the actual game I played White Black's king went to the queenside,
so my king had free reign on the kingside. We both promoted and drew by
threefold repetition.
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Date: 12 Aug 2006 19:27:27
From: Ray Gordon
Subject: Re: Can White draw this pawn endgame?
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> With best play, can White draw this endgame against Black?
1....b5 would seem to win for Black, but endgames are tricky.
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Date: 12 Aug 2006 13:47:08
From: Enrico B. A.
Subject: Re: Can White draw this pawn endgame?
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[email protected] wrote:
> Enrico B. A. wrote:
>
> Here's your game a move before mate. Readers, can you spot the
> mate-in-one? ;-)
>
> FEN: 8/8/6K1/8/8/3k4/5q2/3qqq1q b - - 0 73
> Diagram: http://tinyurl.com/mdnsd
ahahahha ROTFL !!
hmmm I agree: it's a challenge for everyone to spot it...
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Date: 12 Aug 2006 02:34:06
From: [email protected]
Subject: Re: Can White draw this pawn endgame?
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Enrico B. A. wrote:
Here's your game a move before mate. Readers, can you spot the
mate-in-one? ;-)
FEN: 8/8/6K1/8/8/3k4/5q2/3qqq1q b - - 0 73
Diagram: http://tinyurl.com/mdnsd
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Date: 22 Aug 2006 10:48:35
From: David Richerby
Subject: Re: Can White draw this pawn endgame?
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[email protected] <[email protected] > wrote:
> Here's your game a move before mate. Readers, can you spot the
> mate-in-one? ;-)
>
> FEN: 8/8/6K1/8/8/3k4/5q2/3qqq1q b - - 0 73
> Diagram: http://tinyurl.com/mdnsd
It's very bad style to set puzzles with multiple solutions. ;-)
Dave.
--
David Richerby Salted Drink (TM): it's like a
www.chiark.greenend.org.uk/~davidr/ refreshing juice beverage but it's
covered in salt!
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Date: 11 Aug 2006 11:53:29
From: Enrico B. A.
Subject: Re: Can White draw this pawn endgame?
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[email protected] wrote:
> > Just to add my 2 cents, I did the ending vs. GNU Chess during my lunch break :
>
> That's great! I defeated Crafty (ELO:2657) on my first try, but I
> couldn't defeat Rybka (ELO:3015) until I learned the proper technique.
>
> > 1. Kg1 Ke7 2. Kf1 Kd7 3. Ke2 Kc6 4. Kd3 Kb5 5. g4 Ka4 6. e4 dxe4+ 7.
>
> 6.Kc2 is better, controlling the promotion squares (+4.37 vs +9.29,
> depth=20). Black won't be able to force the promotion, but he'll still
> win eventually by attacking the kingside pawns.
you're right, you need to move the kingside pawns... here's my game w/
6.Kc2
1. Kg1 Ke7 2. Kf1 Kd7 3. Ke2 Kc6 4. Kd3 Kb5 5. g4 Ka4 6. Kc2 g6 7. Kd3
c5
8. Ke2 h5 9. gxh5 gxh5 10. Kd3 Kb3 11. Kd2 c4 12. f4 Kb2 13. f5 b5 14.
Ke2
Kxc3 15. e4 d4 16. Kd1 b4 17. fxe6 fxe6 18. Ke2 b3 19. Kf2 b2 20. Kf3
b1=Q
{Then I started having some fan, notice the final position :-)}
21. Kf2 d3 22. Kg3 d2 23. Kh4 d1=Q 24. h3 Kd3 25. Kg5 c3 26. Kf6 Qb6
27.
Kg7 c2 28. Kh8 c1=Q 29. Kh7 Qbe3 30. Kg7 Qxh3 31. Kf8 h4 32. Ke7 Qhg4
33.
Kd7 h3 34. Ke7 h2 35. Ke8 h1=Q 36. Kd8 Qgxe4 37. Ke8 Qxe5 38. Kf8 Qed5
39.
Ke8 e5 40. Kf8 e4 41. Ke7 e3 42. Kf6 e2 43. Ke7 e1=Q+ 44. Kf6 Qde2 45.
Kg6
Q2f1 46. Kg7 Qcd1 47. Kg6 Q5f3 48. Kg5 Q3f2 49. Kg6 Q2g1#
{computer loses as white} 0-1
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Date: 11 Aug 2006 11:09:59
From: [email protected]
Subject: Re: Can White draw this pawn endgame?
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> Just to add my 2 cents, I did the ending vs. GNU Chess during my lunch break :
That's great! I defeated Crafty (ELO:2657) on my first try, but I
couldn't defeat Rybka (ELO:3015) until I learned the proper technique.
> 1. Kg1 Ke7 2. Kf1 Kd7 3. Ke2 Kc6 4. Kd3 Kb5 5. g4 Ka4 6. e4 dxe4+ 7.
6.Kc2 is better, controlling the promotion squares (+4.37 vs +9.29,
depth=20). Black won't be able to force the promotion, but he'll still
win eventually by attacking the kingside pawns.
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Date: 11 Aug 2006 09:44:51
From: Enrico B. A.
Subject: Re: Can White draw this pawn endgame?
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Just to add my 2 cents, I did the ending vs. GNU Chess during my lunch
break :
1. Kg1 Ke7 2. Kf1 Kd7 3. Ke2 Kc6 4. Kd3 Kb5 5. g4 Ka4 6. e4 dxe4+ 7.
Kxe4
Kb3 8. Kd3 c5 9. g5 b5 10. h4 c4+ 11. Kd4 b4 12. h5 bxc3 13. g6 hxg6
14. h6
gxh6 15. Ke3 c2 16. Kd2 Kb2 17. Ke3 c1=Q+
pretty easy even for me (unrated). I don't think W can draw if B has
the best play.
-enrico
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Date: 10 Aug 2006 12:52:21
From: [email protected]
Subject: Re: Can White draw this pawn endgame?
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Ron wrote:
> The winning strategy is simple. Black will create a queenside passed
> pawn. He will then use this pawn - and his king - to drive back the
> white king.
> His aim is for a position where, after trading his c-pawn for white's
> b-pawn, black's now-passed c-pawn is on c2. The black king is on d3, and
> the white king is on c1. Now black abandons his c-pawn and attacks the
> white pawns from the side/behind.
I read this before, but I've never had a chance to practice it in a
real game. It's much clearer now, after reading through your
explanations and lines.
> White shouldn't be able to counter this by going after the kingside,
> because that plan is simply too slow. Black can create a passed pawn too
> quickly.
In the real game I was White. You have to find some counterplay or
resign. In this case I got lucky, and managed a draw.
> Maybe there's a sophisticated subtlety that I'm missing here, but I
> doubt it.
The subtlety is that f6? exf6 gxf6 is not just bad form, it allows
White to create a passed pawn and draw the game. Moving the h-pawn has
a similar effect.
> I don't understand this at all. Who cares about the opposition?
> Furthermore, this allows white to liquidate his weakest pawn.
> So instead of ...f6, 32. ... Kb5! (your move numbers seem a little
> messed up) 33. Kb3 c5 34.Kc3 c4.
Doh!
> There are lots of ways for white to play here, but I don't think they
> make any difference:
>
> 35.h4 Kc5 36.g5 g6 37.f4 h5 38.g5
>
> Now black can be fancy or methodical:
>
> fancy: 38. ... d4+ 39.ed Kd5! 40.Kc2 Kxd4 41.Kd2 Ke4 etc ... white will
> lose all his kingside pawns.
That's nice. White is completely knocked out within a few moves.
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Date: 10 Aug 2006 12:24:13
From: [email protected]
Subject: Re: Can White draw this pawn endgame?
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David Richerby wrote:
> So I'd go for something like
>
> [FEN "5k2/2p2ppp/1p2p3/3pP3/8/2P1P3/5PPP/6K1 b - - 0 1"]
> [SetUp "1"]
>
> 1... Ke7 2.Kf1 Kd7 3.Ke2 Kc6 4.Kd3 Kb5 5.f4 c5 6.g4 Ka4 7.Kc2 b5 8.h4
> b4 9.cxb4 {Forced, or 9... b3.} Kxb4 10.f5 Kc4 11.f6 g6 12.h5 d4 13.e4
> (13.exd4 Kxd4 {-+}) 13... d3+ 14.Kd2 Kb3 15.Kxd3 c4+ 16.Kd2 Kb2 0-1
I played out the win a few different ways. I get it now, thanks.
continuation #2: 1...Ke7 2.Kf1 Kd7 3.Ke2 Kc6 4.Kd3 Kc5 5.g4 b5 6.h4 b4
7.Kc2 Kc4 8.cxb4 Kxb4 9.Kd3 c5 10.Kc2 c4 11.h5 c3 12.f3 Kc4 13.f4 Kb4
14.Kb1 Kb3 15.f5 c2+ 16.Kc1 Kc3 17.g5 g6 18.hxg6 hxg6 19.f6 Kd3 20.Kb2
Kd2 21.Kb3 c1=Q *
continuation #1: 1...Ke7 2.Kf1 Kd7 3.Ke2 Kc6 4.Kd3 Kb5 5.g4 Ka4 6.Kc2
Ka3 7.Kd3 c5 8.e4 b5 9.exd5 exd5 10.g5 b4 11.cxb4 cxb4 12.Kd4 b3
13.Kxd5 *
> > Neutralizing the e5 pawn first doesn't help.
>
> Of course not! The e5 pawn is a weakness for White and the last thing
> you want to do is neutralize your opponent's weaknesses.
Oops. In all my tries, at some point I played ...f6?? exf6 gxf6. This
error allowed White to create his own passed pawns and draw.
I thought I needed a lever so my king could have an entryway to gobble
up all the kingside pawns, but pushing the passed pawn, then abandoning
it when my king had a more favorable position than his, worked much
better. I'm lucky my opponent didn't understand this position.
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Date: 10 Aug 2006 07:35:43
From: [email protected]
Subject: Re: Can White draw this pawn endgame?
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David Richerby wrote:
> The position is surely lost. Any one of those problems is often survivable
> but all three once?
It seems like Black should win easily, but in practice:
As White, I drew against a human opponent.
As Black, I could not prove the win against a strong chess engine.
What is the winning technique?
> White has a disadvantage in material (a pawn down)
> pawn structure (an isolated pawn)
Black has two pawns to White's one on the queenside, that's definitely
a weakness.
> pawn structure (doubled pawns)
> king position (Black's already nearer the centre and it's his move too).
That's the crux of the matter. Doubled pawns are not always weak, and
here they prevent Black's king from occupying f6 or d6. That delays his
ch to the center and limits his access to White's kingside pawns.
Neutralizing the e5 pawn first doesn't help. After 25...f6 exf6 26.
gxf6 Black's ch to the center is one step shorter, but it's White's
move.
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Date: 10 Aug 2006 16:41:22
From: Ron
Subject: Re: Can White draw this pawn endgame?
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In article <[email protected] >,
"[email protected]" <[email protected] > wrote:
> It seems like Black should win easily, but in practice:
>
> As White, I drew against a human opponent.
> As Black, I could not prove the win against a strong chess engine.
>
> What is the winning technique?
>
> > White has a disadvantage in material (a pawn down)
> > pawn structure (an isolated pawn)
>
> Black has two pawns to White's one on the queenside, that's definitely
> a weakness.
>
> > pawn structure (doubled pawns)
> > king position (Black's already nearer the centre and it's his move too).
>
> That's the crux of the matter. Doubled pawns are not always weak, and
> here they prevent Black's king from occupying f6 or d6. That delays his
> ch to the center and limits his access to White's kingside pawns.
That shouldn't matter.
The winning strategy is simple. Black will create a queenside passed
pawn. He will then use this pawn - and his king - to drive back the
white king.
His aim is for a position where, after trading his c-pawn for white's
b-pawn, black's now-passed c-pawn is on c2. The black king is on d3, and
the white king is on c1. Now black abandons his c-pawn and attacks the
white pawns from the side/behind.
White shouldn't be able to counter this by going after the kingside,
because that plan is simply too slow. Black can create a passed pawn too
quickly.
Maybe there's a sophisticated subtlety that I'm missing here, but I
doubt it.
In the game you played:
> 25...Ke7 26. Kf1 Kd7 27. Ke2 Kc6 28. Kd3 Kc5
> 26. g3 b5 27. f3 b4 28. Kc2 bxc3 29. Kxc3
> White takes the opposition in return. Second, black needs a way to
> shift his attention to the queenside. We'll make a window.
>
> 29...f6 30. exf6 gxf6 31. Kd3
I don't understand this at all. Who cares about the opposition?
Furthermore, this allows white to liquidate his weakest pawn.
The opposition is not important here because you're not going to queen
your c-pawn, you're going to sacrifice it.
So instead of ...f6, 32. ... Kb5! (your move numbers seem a little
messed up) 33. Kb3 c5 34.Kc3 c4.
Now notice how strong black's position is. He can send his king
anywhere, but the white king can now never go past the fourth rank, or
move to the g-file, else the c-pawn queens.
Now black can transfer his attention to the kingside - even if if means
retreating his king (after all, the black king can't advance!
It's also worth pointing out here that black simply doesn't care who has
the opposition when pawn moves run out. So long as he can keep at least
two of his pawns on the board, it doesn't matter. In most cases a single
kingside pawn will be sufficient. (Because note how, even without the
opposition) black can drive the white king back - and that's his real
goal.
There are lots of ways for white to play here, but I don't think they
make any difference:
35.h4 Kc5 36.g5 g6 37.f4 h5 38.g5
Now black can be fancy or methodical:
fancy: 38. ... d4+ 39.ed Kd5! 40.Kc2 Kxd4 41.Kd2 Ke4 etc ... white will
lose all his kingside pawns.
but even if you don't see the tactic, it's an easy win:
38. ... Kb5 39.Kc2 Kb4 40. Kb2 Kc4 41.Kc1 Kd3, again, winning all the
kingside pawns.
There appears to be a mistake or two in your remaining moves, making it
hard for me to comment on whether you threw away a win later or not. In
particular you give the move b4 when white's king is on that square and
he doesn't have a b-pawn.
-Ron
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Date: 10 Aug 2006 17:14:18
From: David Richerby
Subject: Re: Can White draw this pawn endgame?
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[email protected] <[email protected] > wrote:
> David Richerby wrote:
>> The position is surely lost. Any one of those problems is often
>> survivable but all three once?
>
> It seems like Black should win easily, but in practice:
>
> As White, I drew against a human opponent.
> As Black, I could not prove the win against a strong chess engine.
>
> What is the winning technique?
I've not looked at the position closely but Kf8-e7/e8-d7-c6-b5
followed by c5, Ka4, create a queenside passer and either promote it
or use it a decoy to keep White's king busy while you gobble up his
pawns. Black can ignore any attempt at kingside pawn play by White:
White can't create a passed pawn and the further White's pawns are
from his king, the easier they are to kill. Once the c3 pawn is
traded, Black can play d4 at the right moment, after which the e5 pawn
becomes very weak.
So I'd go for something like
[FEN "5k2/2p2ppp/1p2p3/3pP3/8/2P1P3/5PPP/6K1 b - - 0 1"]
[SetUp "1"]
1... Ke7 2.Kf1 Kd7 3.Ke2 Kc6 4.Kd3 Kb5 5.f4 c5 6.g4 Ka4 7.Kc2 b5 8.h4
b4 9.cxb4 {Forced, or 9... b3.} Kxb4 10.f5 Kc4 11.f6 g6 12.h5 d4 13.e4
(13.exd4 Kxd4 {-+}) 13... d3+ 14.Kd2 Kb3 15.Kxd3 c4+ 16.Kd2 Kb2 0-1
>> White has a disadvantage in material (a pawn down)
>> pawn structure (an isolated pawn)
>
> Black has two pawns to White's one on the queenside, that's definitely
> a weakness.
Two and a half! The d-pawn covers c4.
>> pawn structure (doubled pawns)
>> king position (Black's already nearer the centre and it's his move too).
>
> That's the crux of the matter. Doubled pawns are not always weak,
> and here they prevent Black's king from occupying f6 or d6. That
> delays his ch to the center and limits his access to White's
> kingside pawns.
The Black king doesn't want to go anywhere near f6! The action's on
the queenside. Not being able to go via d6 costs Black a move but,
since he already has a two-move head start on the king ch, that
isn't a problem.
> Neutralizing the e5 pawn first doesn't help.
Of course not! The e5 pawn is a weakness for White and the last thing
you want to do is neutralize your opponent's weaknesses.
Dave.
--
David Richerby Disposable Drink (TM): it's like a
www.chiark.greenend.org.uk/~davidr/ refreshing juice beverage but you
never have to clean it!
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Date: 10 Aug 2006 06:16:27
From: [email protected]
Subject: Re: Can White draw this pawn endgame?
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Crafty is easy to beat, but that engine is rather weak at endgames.
25... Ke7 26. Kf1 Kd7 27. Ke2 Kc6 28. Kd3 Kc5 29. g4 g5 30. h3 b5 31.
f3 b4 32. Kc2 bxc3 33. Kxc3 h6 34. f4 Kb5 35. Kd3 Kb4 36. e4 dxe4+ 37.
Kxe4 c5 38. f5 c4 39. fxe6 fxe6 40. Ke3 c3 41. Kd3 Kb3 42. Kd4 c2 43.
Kc5 c1=Q+
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Date: 10 Aug 2006 05:50:44
From: [email protected]
Subject: Re: Can White draw this pawn endgame?
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[email protected] wrote:
> With best play, can White draw this endgame against Black?
>
> FEN: 5k2/2p2ppp/1p2p3/3pP3/8/2P1P3/5PPP/6K1 b - - 0 25
> Diagram: http://tinyurl.com/mkpfb
I decided to play this against a strong chess computer (10s/move).
First, Black wants to threaten to promote his passed pawns. To do that,
he'll capture or exchange away White's c3 pawn. His king only needs to
make it to c5, and he can beat White in a direct race to that square.
25...Ke7 26. Kf1 Kd7 27. Ke2 Kc6 28. Kd3 Kc5
Now we exchange away the c3 pawn.
26. g3 b5 27. f3 b4 28. Kc2 bxc3 29. Kxc3
White takes the opposition in return. Second, black needs a way to
shift his attention to the queenside. We'll make a window.
29...f6 30. exf6 gxf6 31. Kd3
White's stepped to the queenside. Black outflanks and moves towards
promotion.
31...Kb4 32. g4 b4 33. Kc2 Kc4 34. f4
d4! will form invincible connected passed pawns, or allow Black's king
free access to the queenside.
34...d4! 35. e4
Black has a won game. It only looks even. He can leave the connected
passed pawns and go to work on the queenside without worrying (as long
as we can get to them before they promote, of course, and that seems
likely).
35...Kb5 36. h4 Kc6 37. g5 fxg5 38. fxg5 Kd6 39. h5 Ke7 40. e5 Kf7 41.
Kb3 Kg7
The chess program still thinks it has a draw, but it's last two
semi-random moves prove it has no way to make progress.
42. Kc4 h6 43. g6
Uhoh. This looks like a draw... drat. So we've shown once again in
practice this game can be drawn, but with best play, should White be
able to draw?
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Date: 10 Aug 2006 14:55:03
From: David Richerby
Subject: Re: Can White draw this pawn endgame?
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[email protected] <[email protected] > wrote:
> [email protected] wrote:
>> With best play, can White draw this endgame against Black?
>>
>> FEN: 5k2/2p2ppp/1p2p3/3pP3/8/2P1P3/5PPP/6K1 b - - 0 25
>> Diagram: http://tinyurl.com/mkpfb
>
> I decided to play this against a strong chess computer (10s/move).
Even strong computers don't always exhibit the long-range planning
needed to win endgames and this is a long way from tablebases. I'd be
very wary of conclusions drawn from such an exercise, especially at
10s/move.
The position is surely lost: White has a disadvantage in material (a
pawn down), pawn structure (doubled pawns and an isolated pawn) and
king position (Black's already nearer the centre and it's his move,
too). Any one of those problems is often survivable but all three at
once?
Dave.
--
David Richerby Technicolor.com (TM): it's like
www.chiark.greenend.org.uk/~davidr/ an E-commerce portal but it's in
realistic colour!
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