Evil endings that embarrass engines

Technical questions regarding Openings, Middlegames, Endings etc.
Dan O'Dowd
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Evil endings that embarrass engines

Post by Dan O'Dowd » Sun Apr 21, 2013 2:07 am

Hey all,

While annotating (without an engine - I'm resolving not to use any engine again for annotation of any game except at the British tournaments for obvious reasons, this year) a game I played last Saturday, I came across a line where I could have ended up with a Bishop for 3 pawns. Feeling masochistic and curious, I decided to play out the stem imbalance position against the engine a few times, but it's the sort of game where any engine just plays horribly anti-strategic moves a lot.



White to move, what do you esteemed strong players on here think - is this the sort of thing that offers scope for winning chances on both sides at a high level, or is this a position where Black must be the only one who can try to win? Makes a nice position to play out anyways!
Last edited by Dan O'Dowd on Fri May 24, 2013 6:58 pm, edited 1 time in total.

Roger de Coverly
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Re: K+B+4P v K+7P

Post by Roger de Coverly » Sun Apr 21, 2013 9:33 am

Dan O'Dowd wrote: is this the sort of thing that offers scope for winning chances on both sides at a high level, or is this a position where Black must be the only one who can try to win?
I would suspect both players would try to secure at least a draw. I could potentially see how Black can lose, by advancing the pawns too far, equally that's how he'll win by advancing pawns and the King together. Alternatively he can draw by using the pawns as a blanket to stop White being able to try anything.

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Greg Breed
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Re: K+B+4P v K+7P

Post by Greg Breed » Sun Apr 21, 2013 11:33 am

I would prefer Black here. The White g and h pawns are on the same colour as his Bishop so the Black King can infiltrate on the dark squares allowing him to push e5. There's also b6 followed by c5 to consider.
If the black King gets to g5 then f5 is in the air allowing Black to pester the h pawn and create more passed pawns. Either way I would think White has the defensive task and Black the attacking possibilities.
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Christopher Kreuzer
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Re: K+B+4P v K+7P

Post by Christopher Kreuzer » Sun Apr 21, 2013 2:48 pm

As Black here, I would play for a win, concentrating on the queenside and attempting to make progress there and in the centre, hoping that if things go wrong that it will be possible to liquidate into at least an endgame with no White pawns, or at worst one where White only has the h-pawn left (which is the wrong colour for the bishop for the queening square of h8). As White I would be looking to be alert for chances to sacrifice the bishop for two pawns in the right sort of positions, plus tactics against b7 if Black misplays the next few moves.

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Re: Evil endings that embarrass engines

Post by Dan O'Dowd » Fri May 24, 2013 7:01 pm

In the same game, I've found another belter that could have come about.


White to move.
To my mind Black looks like the only one who can play for a win here but it wouldn't be easy.

I'm also looking at an inferior ending in a variation (Black could instead of this have gone into a clearly won B+3P v 4P ending) and would appreciate some opinion.


Black to move.
White's Rook is so active here! My intuition is this can be drawn with best play for White if he is circumspect with his King and is willing to loiter around for a good 40 moves. By the way, once I finish annotating this whole game (which is a beastly undertaking since it was so messy), I'll post it up. Thoughts? :) And just to reiterate, please, NO engine opinions since those won't help at all :)

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Jesper Norgaard
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Re: Evil endings that embarrass engines

Post by Jesper Norgaard » Thu Dec 26, 2013 9:06 am



Black to move and win. My engines don't find it, so I win with Black and draw with White. That is surely unusual, normally if there is a win in a position, you won't be able to defend against a computer. Suggestions?

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Tristan Clayton
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Re: Evil endings that embarrass engines

Post by Tristan Clayton » Thu Dec 26, 2013 10:12 am

I'd start with ...fxe3! :)
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Re: Evil endings that embarrass engines

Post by stevencarr » Thu Dec 26, 2013 11:01 am

Tristan Clayton wrote:I'd start with ...fxe3! :)
Err,,, In that case, how did the Bishop get out?

Answer. It is not the f1-Bishop, it is a promoted pawn!

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Jesper Norgaard
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Re: Evil endings that embarrass engines

Post by Jesper Norgaard » Thu Dec 26, 2013 5:22 pm

Ho-ho-ho, no the bishop is not a promoted pawn, so fxe3 is not possible. No Christmas present hidden in this position. The engines start with 1...Ne2+ 2.Kh2 Kf2 3.Bb3 which is fine. Keeping the white king locked in on h2/h1 is an essential element in this endgame. Now what?


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IM Jack Rudd
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Re: Evil endings that embarrass engines

Post by IM Jack Rudd » Thu Dec 26, 2013 6:50 pm

I want to get that knight to g2 somehow. Can we use corresponding squares, or something like that?

If I get the knight to e3 or e1, I win the pawn and the game. Therefore, white must stop me getting the knight to c4, c2, d3 or d1. Thus:

Nd4: bishop must be on a4, b1, d1, d3
Na3: bishop must be on b3, d3
Nc3: bishop must be on b3, c2
Nb4: bishop must be on b1
Nb2: ....

So b2 is a winning square for the knight - which means a4 is as well. Thus:

Nc5: bishop must be on b5, c2
Nb6: bishop must be on b5, b3

Hmmm. Is this getting us anywhere? (I can quite clearly see that it would be beyond the Event Horizon.)

Martin Benjamin
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Re: Evil endings that embarrass engines

Post by Martin Benjamin » Thu Dec 26, 2013 7:37 pm

Dan O'Dowd wrote:Hey all,

While annotating (without an engine - I'm resolving not to use any engine again for annotation of any game except at the British tournaments for obvious reasons, this year) a game I played last Saturday, I came across a line where I could have ended up with a Bishop for 3 pawns. Feeling masochistic and curious, I decided to play out the stem imbalance position against the engine a few times, but it's the sort of game where any engine just plays horribly anti-strategic moves a lot.



White to move, what do you esteemed strong players on here think - is this the sort of thing that offers scope for winning chances on both sides at a high level, or is this a position where Black must be the only one who can try to win? Makes a nice position to play out anyways!

You are looking for stronger players than I (grade in steep decline), but I was interested in the opinions already expressed which all preferred Black. My instinct would be to take White, as with play still available on both sides of the board, the lone bishop will soon be at its most effective. White centralises his king and then Black has to start making crucial decisions about how to proceed. The classic example of a bishop v pawns ending would be game 1 of the 1972 World Championship match, which is tricky and may have still been drawn with best play even after Fischer's needless Bxh2, but Black had to find accurate moves all the way. I am not saying that White is winning with best play by any means, but I think Black has far less margin for error/manoeuvring. You can retract bishop moves, but not pawn moves.

Edit: "Retract" in the sense of returning it to an earlier location on a later move, not "J'adoubovic" in the style of a recently departed GM.

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Re: Evil endings that embarrass engines

Post by Martin Benjamin » Thu Dec 26, 2013 8:26 pm



Petrosyan v Hazai 1970, which I found the other day flicking idly through the instructive and entertaining "Blunders and Brilliancies" by Ian Mullen and Moe Moss. Black played 1.....Qb6 and after 2 Nxb6 cxb6, it was a draw. Black will play ...h4 if allowed, so if White plays 3 h4, Black draws after gxh4 followed by h3 and h4, maintaining the blockade. White should have smelled a rat, and it does not take much thought to see that 2 Qd2 and moving the king to a4 to win the a pawn was the winning manoeuvre. I ought to kick my older son off the family laptop, dust off Fritz 13 and see what the computer choice is, but as I am still recovering from illness, and he is bigger than I am now, maybe someone else would like to try it on some chess software.

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Re: Evil endings that embarrass engines

Post by Ray Sayers » Thu Dec 26, 2013 9:09 pm

IM Jack Rudd wrote:I want to get that knight to g2 somehow. Can we use corresponding squares, or something like that?

If I get the knight to e3 or e1, I win the pawn and the game. Therefore, white must stop me getting the knight to c4, c2, d3 or d1. Thus:

Nd4: bishop must be on a4, b1, d1, d3
Na3: bishop must be on b3, d3
Nc3: bishop must be on b3, c2
Nb4: bishop must be on b1
Nb2: ....

So b2 is a winning square for the knight - which means a4 is as well. Thus:

Nc5: bishop must be on b5, c2
Nb6: bishop must be on b5, b3

Hmmm. Is this getting us anywhere? (I can quite clearly see that it would be beyond the Event Horizon.)
That was pretty much my thinking too; win the g2 pawn. I'll be blowed if I can see how to force it there though. I gave up, figuring I must be a) missing something obvious or b) barking up the wrong tree.

I would be grateful for the solution!

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Re: Evil endings that embarrass engines

Post by Roger de Coverly » Thu Dec 26, 2013 9:12 pm

Martin Benjamin wrote: maybe someone else would like to try it on some chess software.
An interesting test to see which engines overcome the horizon effect or have some part of their expert knowledge coded to avoid totally blocked positions.

They either have to "know" that there's no breakthrough after the queen is taken and the tactical play with the h pawn, or be able to find it by eventually running into a 50 move or 3-fold repetition. I suppose it might eventually offer to trade the Queen for a Bishop to avoid the 50 move draw.

Incidentally, it might look like a Tigran position, but it was actually Arshak. There has been discussion about it at the chessgames site
http://www.chessgames.com/perl/chessgame?gid=1281614

Ray Sayers

Re: Evil endings that embarrass engines

Post by Ray Sayers » Thu Dec 26, 2013 9:15 pm

Martin Benjamin wrote:
Dan O'Dowd wrote:Hey all,

While annotating (without an engine - I'm resolving not to use any engine again for annotation of any game except at the British tournaments for obvious reasons, this year) a game I played last Saturday, I came across a line where I could have ended up with a Bishop for 3 pawns. Feeling masochistic and curious, I decided to play out the stem imbalance position against the engine a few times, but it's the sort of game where any engine just plays horribly anti-strategic moves a lot.



White to move, what do you esteemed strong players on here think - is this the sort of thing that offers scope for winning chances on both sides at a high level, or is this a position where Black must be the only one who can try to win? Makes a nice position to play out anyways!

You are looking for stronger players than I (grade in steep decline), but I was interested in the opinions already expressed which all preferred Black. My instinct would be to take White, as with play still available on both sides of the board, the lone bishop will soon be at its most effective. White centralises his king and then Black has to start making crucial decisions about how to proceed. The classic example of a bishop v pawns ending would be game 1 of the 1972 World Championship match, which is tricky and may have still been drawn with best play even after Fischer's needless Bxh2, but Black had to find accurate moves all the way. I am not saying that White is winning with best play by any means, but I think Black has far less margin for error/manoeuvring. You can retract bishop moves, but not pawn moves.

Edit: "Retract" in the sense of returning it to an earlier location on a later move, not "J'adoubovic" in the style of a recently departed GM.
I think if Black just didn't want to lose he can play b5, f6, K to d6 and sit. Play e5+ if Kd4.

So Black seems to have at least a draw, so I would rather be Black! ('2 results').