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Re: Cursed win at TCEC

Posted: Thu Nov 17, 2016 8:41 am
by syzygy
mwyoung wrote:
syzygy wrote:
Lets make an absurd example to show the point. I play GM Carlsen a 6 game match with 6 fixed and very unsound openings. So unsound I am able to win with white every game. And so is GM Carlsen.
And that is exactly what is not happening in TCEC.
I respect your opinion.

And I will let TCEC make my point.
It is not an opinion but a fact. There have not been any 1-1 openings so far.

Of course we might yet get openings that are so advantageous for one side that 1-1 is inevitable. But as hgm explained, even if that happens there is no damage. It will be as if TCEC had one round less. There would be no actual skew.

Re: Cursed win at TCEC

Posted: Thu Nov 17, 2016 9:07 am
by Sven
Dirt wrote:
Sven Schüle wrote:For the future I suggest to add a clarification to the rules saying that adjudicating a position as a TB win will be skipped if the shortest mate is not possible within the 50-moves rule.
How are you going to manage that? Cutechess does seem to have Syzygy support started, but it is still unreleased as far as I can tell.
I wrote "for the future", not for the current TCEC season. That should be possible. Of course following my suggestion would require appropriate tool support.

Re: Cursed win at TCEC

Posted: Thu Nov 17, 2016 9:13 am
by Laskos
syzygy wrote:
mwyoung wrote:
syzygy wrote:
Lets make an absurd example to show the point. I play GM Carlsen a 6 game match with 6 fixed and very unsound openings. So unsound I am able to win with white every game. And so is GM Carlsen.
And that is exactly what is not happening in TCEC.
I respect your opinion.

And I will let TCEC make my point.
It is not an opinion but a fact. There have not been any 1-1 openings so far.

Of course we might yet get openings that are so advantageous for one side that 1-1 is inevitable. But as hgm explained, even if that happens there is no damage. It will be as if TCEC had one round less. There would be no actual skew.
I have shown here:
http://www.talkchess.com/forum/viewtopi ... 45&start=0
that borderline, unbalanced openings (roughly 50% White wins and 50% draws, with very few Black wins) are more sensitive in discerning the strength difference, especially in TCEC conditions, where the draw rate from balanced openings can reach 90%. In both BayesElo and Davidson draw models. TCEC is right using unbalanced positions.

Re: fortress_draw_rule

Posted: Thu Nov 17, 2016 9:36 am
by Rochester
You want play different game but this game is not your thinking.

Re: Cursed win at TCEC

Posted: Thu Nov 17, 2016 9:46 am
by mohanjay
ICCF adjudicates positions as won once a Tablebase is reached even if the moves required to win are more than 50 - implying FIDE rules of chess have been overridden in Correspondence Chess. Computer chess should also follow similar principles (though the TCEC rules are ambiguous in the current scenario)

Re: Cursed win at TCEC

Posted: Thu Nov 17, 2016 9:56 am
by hgm
Dirt wrote:
bnemias wrote:The wider TCEC solution isn't so clear because it is possible to have one engine using Gaviota while the other is using Syzygy (or no TB). Luckily we don't have that case, because I doubt it is possible to adjudicate that case fairly under the current rules.
Nonsense. Syzygy is always right as far as I know. Gaviota can be wrong. If an engine uses Gaviota it has to expect it being wrong sometimes.
I think the point is that an engine using Gaviota might bungle a win that it gets awarded by adjudication with syzygy.

Note that the WinBoard method for quickly ending games that reached the EGT stage would not suffer from that. It would allow the Gaviota-using engine to bungle the win.

Re: Cursed win at TCEC

Posted: Thu Nov 17, 2016 10:36 am
by Lyudmil Tsvetkov
mohanjay wrote:ICCF adjudicates positions as won once a Tablebase is reached even if the moves required to win are more than 50 - implying FIDE rules of chess have been overridden in Correspondence Chess. Computer chess should also follow similar principles (though the TCEC rules are ambiguous in the current scenario)
+10

Re: fortress_draw_rule

Posted: Thu Nov 17, 2016 11:12 am
by Evert
Lyudmil Tsvetkov wrote: Concerning the real TCEC game, this is quite similar to FIDE rules concerning the situation when a player has been flagged, but he has just delivered his opponent a mate. In this case, although the flag of the player is already down, thus losing on time, he still wins the game, fully according to FIDE rules, as there is mate on the board, which overrides flagging.
Correct: I cannot claim a draw by 50 move rule if I have just been mated. Mate tumps the 50 move rule. Conversely, you cannot claim a win by mate-in-two if I can claim draw by 50 move rule first.
Very similarly, based on TCEC special draw rule, the game was declared drawn, but, when Cutechess adjudicated the tablebase position, it adjudicated a win, as the position is simply won. An existing win on the board, which is the case in current game, actually an existing mate, certainly overrides the special TCEC draw rule.
This, however, completely misses the point of what happened here.
The game was not declared a draw, and there was no mate on the board. The game was halted in a position that is drawn under the 50 move rule, but adjudicated as a win because of the existence of a mating line that ignores the 50 move rule.

Now, it could be argued that the referee has no business adjudicating a game as drawn under the 50 move rule: it is up to the player to claim the draw in that case. That is a separate discussion. Of course the UCI protocol lacks a way for engines to do this anyway, which is why the referee makes the claim on behalf of the player.

Re: fortress_draw_rule

Posted: Thu Nov 17, 2016 11:43 am
by hgm
You could also adjudicate this position as a win for white:
[d]7q/8/5k2/8/8/4K3/8/8 w - - 0 1
After all, it is a forced win in 3 (1. Kd4! Kg7 2.Ke5! Kf6 3.Kxf6 Qxf6 1-0). It would be a bit strange to do that in a game of orthodox Chess, however. Even if you announced that 3-men positions would be adjudicated.

Re: Cursed win at TCEC

Posted: Thu Nov 17, 2016 1:03 pm
by Dirt
syzygy wrote:It is not an opinion but a fact. There have not been any 1-1 openings so far.
Rounds 17 and 18 were the same opening and each was won by white. Not unexpected, of course.