Cursed win at TCEC

[Lyudmil Tsvetkov]

no one knows how the game would have ended, as top engine analysis is imperfect, even in relatively simple positions.

I am afraid you have far too little knowledge of the engines and how they deal with tablebases.

It is 100% certain that the game would have ended in a draw. Thanks to its tablebases, H5 knew how to keep the mate beyond the 50-move horizon.

Try it out for yourself:
https://syzygy-tables.info/?fen=K5Q1/8/ ... _b_-_-_0_1

You are white and may play whatever moves you like. Black always plays the move shown at the top.

You won't get DTZ down by more than 1 ply on each move and black won't let DTZ go down by more than 1 ply on each move. Since you start at DTZ=124, you need more than 60 moves to get to a capture or mate. The 50-move rule kicks in after 50 moves. QED.

Now that you have learned something new, you might want to reconsider your earlier statements in this thread.

Rigth, I just start learning about engines and engine code, and often have hell of a time while reading and trying to understand some stuff: for example your SF tbs code, not the easiest code to read, but still understandable.

Nothing to reconsider for me, the GUI already adjudicated. (definitely this will be the longest thread of the year, and Nuno desrves some special prize for starting it)

Whether the game was won or draw depends on where you start analysing, you migth start a few plies earlier or later; in any case, if we are going to follow engine scores, the same way you proceed with your tablebases, then 105cps in the mg is certainly won. But, again, the point is not so much this particular game, but rather why on earth a KNOWN WIN should be adjudicated as a DRAW? Simply because there is some ancient rule concerning fortress drawing?

If we have witnessed at least a couple of similar developments in TCEC with only couple of hundred games played, then you can certainly imagine how many objective wins are adjudicated as artificial draws in a much larger pool of games that is statistically relevant. Why artificially distort the result?

btw., FIDE rules of chess are quite adamant on this: an existing mate on the board overrides any other possible outcome. A tablebase mate in 72 is certainly an existing mate, it should definitely override any other specific ad-hoc rule, like current TCEC draw rule, and the end position, as we all know perfectly well, was simply a mate in 72, rigth?

So, what should be done is for tbs adjudication to fall in line with FIDE rules, and the stupid 50-moves restriction be lifted as soon as possible, only in pawnless endgames.

[Lyudmil Tsvetkov]

[d]4k1n1/8/8/8/8/8/8/2B1KB2 w - - 0 1

why adjudicate above position as a draw, whatever the adjudication rules?
if tablebases are in force, that simply means there is mate on the board. if some software prunes that mate, it is the fault of the software, of course.

do you know how often similar positions occur? (above is mate in 66)

[d]2k1r3/2r5/8/8/8/8/5R2/2BR1K2 w - - 0 1

or, this one (again longer than 50 mate)

do you know how often above correlation occurs?
If I have seen this myself while watching/browsing through engine games at least 5 or 6 times, then it should be relatively frequent. Obviously, any wrong tbs adjudication will only distort the result.

[Uri Blass]

no one knows how the game would have ended, as top engine analysis is imperfect, even in relatively simple positions.

I am afraid you have far too little knowledge of the engines and how they deal with tablebases.

It is 100% certain that the game would have ended in a draw. Thanks to its tablebases, H5 knew how to keep the mate beyond the 50-move horizon.

Try it out for yourself:
https://syzygy-tables.info/?fen=K5Q1/8/ ... _b_-_-_0_1

You are white and may play whatever moves you like. Black always plays the move shown at the top.

You won't get DTZ down by more than 1 ply on each move and black won't let DTZ go down by more than 1 ply on each move. Since you start at DTZ=124, you need more than 60 moves to get to a capture or mate. The 50-move rule kicks in after 50 moves. QED.

Now that you have learned something new, you might want to reconsider your earlier statements in this thread.

Rigth, I just start learning about engines and engine code, and often have hell of a time while reading and trying to understand some stuff: for example your SF tbs code, not the easiest code to read, but still understandable.

Nothing to reconsider for me, the GUI already adjudicated. (definitely this will be the longest thread of the year, and Nuno desrves some special prize for starting it)

Whether the game was won or draw depends on where you start analysing, you migth start a few plies earlier or later; in any case, if we are going to follow engine scores, the same way you proceed with your tablebases, then 105cps in the mg is certainly won. But, again, the point is not so much this particular game, but rather why on earth a KNOWN WIN should be adjudicated as a DRAW? Simply because there is some ancient rule concerning fortress drawing?

If we have witnessed at least a couple of similar developments in TCEC with only couple of hundred games played, then you can certainly imagine how many objective wins are adjudicated as artificial draws in a much larger pool of games that is statistically relevant. Why artificially distort the result?

btw., FIDE rules of chess are quite adamant on this: an existing mate on the board overrides any other possible outcome. A tablebase mate in 72 is certainly an existing mate, it should definitely override any other specific ad-hoc rule, like current TCEC draw rule, and the end position, as we all know perfectly well, was simply a mate in 72, rigth?

So, what should be done is for tbs adjudication to fall in line with FIDE rules, and the stupid 50-moves restriction be lifted as soon as possible, only in pawnless endgames.

chess programs played based on the assumption that there is 50 move rule.
Chess programs are programmed to use rules of game A(with the 50 move rule).

Adjudicating based on rule B without the 50 move rule in 5 piece positions is not fair when you did not tell the programmers in advance about the rules.

Note that using distance to mate and not using the 50 move rule in tablebases also is not going to solve the problem because in this case a program may force 6 piece tablebases position that is mate in 80 but draw by the 50 move rule and TCEC does not adjudicate 6 piece tablebases positions.

If you want programs not to use the 50 move rule you are free to organize your own tournament when you declare the rules before the tournament
and invite programmers to change their programs in order to participate.

[hgm]

btw., FIDE rules of chess are quite adamant on this: an existing mate on the board overrides any other possible outcome. A tablebase mate in 72 is certainly an existing mate, it should definitely override any other specific ad-hoc rule, like current TCEC draw rule, and the end position, as we all know perfectly well, was simply a mate in 72, rigth?

The nonsense you spawn is of such an exceptional quality that I am starting to wonder whether it would not be my duty as moderator to delete it, in order to protect those inadvertantly reading it from brain damage.

The FIDE rule you abusively quote and misinterpret here of course refers to a mate in 0, not to a mate in 72. There is nothing 'existing' on a mate in 72. It is something that might or might not materialize somewhere in the future based on how the players move.

[Lyudmil Tsvetkov]

no one knows how the game would have ended, as top engine analysis is imperfect, even in relatively simple positions.

I am afraid you have far too little knowledge of the engines and how they deal with tablebases.

It is 100% certain that the game would have ended in a draw. Thanks to its tablebases, H5 knew how to keep the mate beyond the 50-move horizon.

Try it out for yourself:
https://syzygy-tables.info/?fen=K5Q1/8/ ... _b_-_-_0_1

You are white and may play whatever moves you like. Black always plays the move shown at the top.

You won't get DTZ down by more than 1 ply on each move and black won't let DTZ go down by more than 1 ply on each move. Since you start at DTZ=124, you need more than 60 moves to get to a capture or mate. The 50-move rule kicks in after 50 moves. QED.

Now that you have learned something new, you might want to reconsider your earlier statements in this thread.

Rigth, I just start learning about engines and engine code, and often have hell of a time while reading and trying to understand some stuff: for example your SF tbs code, not the easiest code to read, but still understandable.

Nothing to reconsider for me, the GUI already adjudicated. (definitely this will be the longest thread of the year, and Nuno desrves some special prize for starting it)

Whether the game was won or draw depends on where you start analysing, you migth start a few plies earlier or later; in any case, if we are going to follow engine scores, the same way you proceed with your tablebases, then 105cps in the mg is certainly won. But, again, the point is not so much this particular game, but rather why on earth a KNOWN WIN should be adjudicated as a DRAW? Simply because there is some ancient rule concerning fortress drawing?

If we have witnessed at least a couple of similar developments in TCEC with only couple of hundred games played, then you can certainly imagine how many objective wins are adjudicated as artificial draws in a much larger pool of games that is statistically relevant. Why artificially distort the result?

btw., FIDE rules of chess are quite adamant on this: an existing mate on the board overrides any other possible outcome. A tablebase mate in 72 is certainly an existing mate, it should definitely override any other specific ad-hoc rule, like current TCEC draw rule, and the end position, as we all know perfectly well, was simply a mate in 72, rigth?

So, what should be done is for tbs adjudication to fall in line with FIDE rules, and the stupid 50-moves restriction be lifted as soon as possible, only in pawnless endgames.

chess programs played based on the assumption that there is 50 move rule.
Chess programs are programmed to use rules of game A(with the 50 move rule).

Adjudicating based on rule B without the 50 move rule in 5 piece positions is not fair when you did not tell the programmers in advance about the rules.

Note that using distance to mate and not using the 50 move rule in tablebases also is not going to solve the problem because in this case a program may force 6 piece tablebases position that is mate in 80 but draw by the 50 move rule and TCEC does not adjudicate 6 piece tablebases positions.

If you want programs not to use the 50 move rule you are free to organize your own tournament when you declare the rules before the tournament
and invite programmers to change their programs in order to participate.

all programmers that sent engines knew in advance what the rules would be, rigth?
the fact that a bug is discovered in the process of the tournament, actually a good bug, does not mean engine authors did not have foreknowledge of the rules, they did.

besides, this tournament is supposed to be automated, rigth?

you wanna instruct the TD to change the game result and spark another outcry along the lines of the outcry against Komodo team when they lost their first game to H5 in stage 3? I guess then everyone agreed this should not have been done, but now suddenly everyone supports the opposite opinion.

why should anything be changed, when everything is automated and the GUI says black loses?

[Lyudmil Tsvetkov]

In case we do not solve this discussion in the next 2 and a half months, I suggest we go get Miguel and give him a good lashing.

[Maharadja]

btw., FIDE rules of chess are quite adamant on this: an existing mate on the board overrides any other possible outcome.

Sometimes it takes me more than 50 moves to mate with bishop and knight.
So when my opponent claims the 50 move rule after 50 moves I can show him this rule, no?

[hgm]

That the tournament is automated is not a rule, but just for convenience. If the automation malfunctions, e.g. because the GUI crashes, or they suffer a power blackout, they would obviously interfere, and restart it by hand, rather than declare the tournament finished.

[Lyudmil Tsvetkov]

That the tournament is automated is not a rule, but just for convenience. If the automation malfunctions, e.g. because the GUI crashes, or they suffer a power blackout, they would obviously interfere, and restart it by hand, rather than declare the tournament finished.

also in the case of a huge meteorite crashing somewhere close to Denmark, alien invasion, etc.

[Lyudmil Tsvetkov]

btw., FIDE rules of chess are quite adamant on this: an existing mate on the board overrides any other possible outcome. A tablebase mate in 72 is certainly an existing mate, it should definitely override any other specific ad-hoc rule, like current TCEC draw rule, and the end position, as we all know perfectly well, was simply a mate in 72, rigth?

The nonsense you spawn is of such an exceptional quality that I am starting to wonder whether it would not be my duty as moderator to delete it, in order to protect those inadvertantly reading it from brain damage.

The FIDE rule you abusively quote and misinterpret here of course refers to a mate in 0, not to a mate in 72. There is nothing 'existing' on a mate in 72. It is something that might or might not materialize somewhere in the future based on how the players move.

you migth delete whatever you want, would not be the first time; persons who say the truth are usually persecuted.

mate in 72=mate in 0 + tablebase adjudication, I think this is very obvious

following your logic of thought, a drawn tbs position is not a draw, because the draw is achieved in another 40 or so moves.

as soon as a tb position is reached, it gets adjudicated, an in the present case the tb position is a win, and the particular win=mate.