Cursed win at TCEC

[Rochester]

You want play different game but this game is not your thinking.

[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)

[hgm]

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.

[Lyudmil Tsvetkov]

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

[Evert]

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.

[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.

[Dirt]

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.

[Guenther]

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.

uhhmm... game 17 is the cursed win which was wrongly adjusticated

[MikeB]

Yea it pretty funny all over a 1/2 point between two chess engines and the only thing at stake is bragging rights. we need to move on. Oh. .. and do me a favor , next time try to get it right 😉

[Norm Pollock]

The fundamental unresolved issue has been around a long time, and it will be around long after tcec. What it comes down to is why should computer engines that see a mate in 51+ moves be penalized and forced to accept a draw. The 50 move rule was established solely for humans and it was established long before computer engines. Should it be changed to accommodate technological progress and if so, how?

As for this tournament and superfinal itself, no big deal, but the incident illustrates the bigger problem that is unresolved.