Cursed win at TCEC

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Evert
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Re: fortress_draw_rule

Post by Evert » Sat Nov 26, 2016 9:44 am

Lyudmil Tsvetkov wrote: we are talking about the most popular, and by far, chess mainstream variant, so no need to change basic rules, we would like to just change outdated/meaningless rules.
We are? Sorry, I thought we were talking about Orthodox Chess.
I agree with you that the Chase rules could do with some cleanup/stream-lining for engine play.

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Re: fortress_draw_rule

Post by hgm » Sat Nov 26, 2016 10:11 am

Lyudmil Tsvetkov wrote:Why not add a paragraph or 2 in UCI/winboard protocols, with following text:

' Engines implementing the UCI/winboard protocol follow the FIDE Rules of Chess, with the exception of the 50-moves rule.

For the purposes of engine competition, the FIDE 50-moves rule is transformed into 2 subrules:

1. the general 50-moves FIDE rule applies throughout the game, with the exception of pawnless endgames.
2. only in pawnless endgames, the 50-moves rule is extended to 550-moves rule (the longest known such mate being 1090 plies), to accomodate relevant winning positions.'

very consise, and very reasonable.
Very bad idea. For one it would mean that games would drag on nearly forever if they happen to reach KBBKN (or KQKQ), and the engines do not know how to win it (as would almost always be the case).

And of course this is not a protocol matter. You are just changing the rules of the game, and protocols do not involve themselves with the rules. In fact you are defining just another Chess variant, and WB and UCI already have g eeral mechanisms for handling variants. Just let the engine report they play 'variant fivehundredfifty', and then run a tourney for this variant.

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Evert
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Re: fortress_draw_rule

Post by Evert » Sat Nov 26, 2016 10:29 am

Evert wrote: I'll ask you again: how is it more unjust to be deprived of a win than to be deprived of a draw?
Let me rephrase this differently.

Once upon a time, it was realised that there are 5-men positions that could be won, except for the 50-move rule kicking in (I remember it came up during a Timman-Yusupov game). In current parlance, they are cursed wins. This was deemed unfair, and the rule was changed so it was 50 moves, except in certain endings where it was 75.
Just a few years later, more cursed wins, with longer move chains, were discovered. It was realised that the rule as it was just made arbitrary exceptions, and was not fair. So a choice had to be made:
1. Keep the unfair rule as it was.
2. Revise the rule every time a new cursed win was found.
3. Abolish the rule entirely.
4. Revert to the plain 50-move rule.

Obviously, 4 was the choice made. The other options all have more undesirable features (arbitrary, not scalable, open for abuse).

Now, you claim that the existence of cursed wins makes the game less interesting, at least for computer chess, and the cursed wins should be treated as normal wins. In effect, this is option (2) above, but we might as well consider (3) because as technology improves, that's what it'd end up coming down to anyway. Does this make for a better game? I'll argue why I think it does not. You're free, of course, to push for your "Tsvetkov's Chess" that has different rules.

First of all, many of these extremely long wins feature move sequences that are utterly incomprehensible. Is it interesting as a spectator game? Not really.
More importantly, the game-theoretic value of the opening position of FIDE Chess is (almost certainly) a draw. It's possible that this is entirely due to the 50-move rule. We don't know the outcome of Chess without this rule. If it's still a draw, then it doesn't really matter much in the end. On the other hand, perhaps the opening position is really a cursed win. If that is the case, abandoning the 50-move rule makes the game a win for white.

So, what is more interesting: a game where Black's job is to defend the draw and keep White from winning by playing accurately, or a game where Black's job is to hope White makes a mistake, because there's nothing he/she can actually do themselves to affect the outcome of the game?

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Re: fortress_draw_rule

Post by hgm » Sat Nov 26, 2016 10:36 am

It would certainly be a big time saver if we could adjudicate the game as a win to white even before any moves were done! Then we could all focus on serious business. :idea:

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Re: fortress_draw_rule

Post by syzygy » Sat Nov 26, 2016 11:00 am

Lyudmil Tsvetkov wrote:what about picking the best move controversy?

By keeping the 50-move rule/restriction, SF obviously chooses and plays suboptimal moves. Why do that? Is not the purpose of chess programming finding the best move?
SF will avoid the 50-move draw (which it internally scores as about +0.003) in favour of the far better move that keeps the pieces on the board in the hope of finding a real win.

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Re: fortress_draw_rule

Post by syzygy » Sat Nov 26, 2016 11:14 am

Evert wrote:
Lyudmil Tsvetkov wrote: when you know there is mate in 80 not involving any pushes/captures, you should give the engine 80 moves' time to deliver that mate, otherwise you are acting unjust to the engine, and chess in general as well.
So you say.
Yet you have repeatedly failed to demonstrate why that would be so.

I'll ask you again: how is it more unjust to be deprived of a win than to be deprived of a draw?
In Timman-Velimirovic, played without the help of computers, white had a "winning" KRPvKBP position but had to struggle against the 50-move rule to convert it (in which he finally succeeded). I don't believe anyone at that time seriously suggested that white should get its "well-deserved" point without playing out the position. Or that the 50-move rule should be somehow changed so that such endings in the future would not be influenced by the 50-move rule.

Being efficient with your (fifty) moves is just part of the game. If the opponent can delay you enough, he gets a well-deserved draw. Just like a player can lose a pawn but still draw the game. (But I have a proposal: when the game reaches a position with 7 pieces/pawns on the board, the side having more pieces immediately wins. This gets rids of all TB draws and gives excellent compression of 7-piece TBs.)

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Re: fortress_draw_rule

Post by syzygy » Sat Nov 26, 2016 11:41 am

syzygy wrote:In Timman-Velimirovic, played without the help of computers, white had a "winning" KRPvKBP position but had to struggle against the 50-move rule to convert it (in which he finally succeeded). I don't believe anyone at that time seriously suggested that white should get its "well-deserved" point without playing out the position. Or that the 50-move rule should be somehow changed so that such endings in the future would not be influenced by the 50-move rule.
Maybe this has to be relativised. At least the "general public" in Holland at the time "was incensed by the injustice of it".
http://russell-enterprises.com/hans19.html
Hans Ree wrote:According to the highest authority at that time, the series of endgame books by the great analyst André Chéron, this position was objectively winning for White, but impossible to win in practice, because of the 50-move rule. In fact the last capture had been at move 64, so Timman’s time was running out.

The Dutch chess public was incensed by the injustice of it and the fire of sadness and anger was stoked up by Hein Donner, who in his newspaper de Volkskrant wrote five highly emotional articles about this game, the first one on October 4, at the first adjournment, and the final one on October 20, after Timman’s eventual victory.

The dates show how long a game could drag on in those days of adjournments. But looking at Donner’s articles now, I am mostly struck by the liberties allowed then to a chess journalist in one of the most popular Dutch newspapers. Five articles about one game. And by far the longest of these was not about breaking news, but a background article: a highly technical and detailed explanation of Chéron’s winning method for White from the diagram position, which tended to show that Timman would only be able to capture the pawn at a3 on move 128, while according to FIDE’s rules he had only until move 114 to do so.

Many Dutch amateur analysts tried to shorten the winning process and implored Donner that he should phone Timman in Rio de Janeiro to communicate their findings. Donner wisely refrained and in fact it turned out that Timman and his second Ulf Andersson had indeed managed to shorten Chéron’s winning method considerably.

Timman won the game; the Dutch chess world was jubilant. Timman was expected to qualify for the Candidates matches after all. But then in the final round (round 19!) some things went badly wrong for Timman and he missed qualification anyway.

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Re: fortress_draw_rule

Post by Lyudmil Tsvetkov » Sat Nov 26, 2016 11:44 am

syzygy wrote:
Lyudmil Tsvetkov wrote:what about picking the best move controversy?

By keeping the 50-move rule/restriction, SF obviously chooses and plays suboptimal moves. Why do that? Is not the purpose of chess programming finding the best move?
SF will avoid the 50-move draw (which it internally scores as about +0.003) in favour of the far better move that keeps the pieces on the board in the hope of finding a real win.
but the 50-move draw is actually a win chesswise, while, quite frequently, epseically in the eg, 30-40-50cps 'winning' scores are actually draws.

without the restriction, SF would pick the objectively best longer than-50-move win. problem is, that happens frequently during search, and also is stats/tuning relevant.

I guess human can afford a 50-move restriction, for different reasons, but not top engines, aspiring to play perfect chess, especially when they never get tired, and playing couple hundred more moves is not an issue.

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Re: fortress_draw_rule

Post by hgm » Sat Nov 26, 2016 11:47 am

'Objectively best' only in your imagination, of course, and by the rest of the Chess-playing world considered the 'ultimately stupid' move...

And what about the human audience getting tired of it? Or should we drop teh 50-move rule only for matches played by computers AND watch by computers? :lol:

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Re: fortress_draw_rule

Post by Lyudmil Tsvetkov » Sat Nov 26, 2016 11:56 am

hgm wrote:
Lyudmil Tsvetkov wrote:Why not add a paragraph or 2 in UCI/winboard protocols, with following text:

' Engines implementing the UCI/winboard protocol follow the FIDE Rules of Chess, with the exception of the 50-moves rule.

For the purposes of engine competition, the FIDE 50-moves rule is transformed into 2 subrules:

1. the general 50-moves FIDE rule applies throughout the game, with the exception of pawnless endgames.
2. only in pawnless endgames, the 50-moves rule is extended to 550-moves rule (the longest known such mate being 1090 plies), to accomodate relevant winning positions.'

very consise, and very reasonable.
Very bad idea. For one it would mean that games would drag on nearly forever if they happen to reach KBBKN (or KQKQ), and the engines do not know how to win it (as would almost always be the case).

And of course this is not a protocol matter. You are just changing the rules of the game, and protocols do not involve themselves with the rules. In fact you are defining just another Chess variant, and WB and UCI already have g eeral mechanisms for handling variants. Just let the engine report they play 'variant fivehundredfifty', and then run a tourney for this variant.
excellent suggestion.

550 will become the mainstream variant (deservedly so), while authors could also include outdated variants like 50-moves. In this way no one will suffer, but the mainstream will be what makes more sense.

of course, any decent engine will win the aforementioned endings, and when I say any, I mean any. At least the tops would handle that easily, but are not all other engines following the tops' example, getting stronger and stronger with time?

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