Cursed win at TCEC

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Lyudmil Tsvetkov
Posts: 6031
Joined: Tue Jun 12, 2012 10:41 am

Re: fortress_draw_rule

Post by Lyudmil Tsvetkov » Fri Nov 25, 2016 8:32 am

Evert wrote:
Lyudmil Tsvetkov wrote:
Evert wrote:
Lyudmil Tsvetkov wrote:[d]8/4n3/4k3/8/8/4K1B1/2B5/8 w - - 0 1

why instruct the engine above position is a draw, when SF finds mate very quickly even at bullet?
I'm not sure what point you think you're making?
The position is apparently mate in 43 moves (starting with 1. Bb3+), so the 50 move rule is irrelevant even if the knight is not captured (which I haven't checked). Source: Nalimov tables from http://www.k4it.de/?topic=egtb&lang=en.
If you're saying adjudicating a game deprives the engine of the ability to mishandle a position, or swindle it's opponent, sure. Different discussion though.
score rises from 5 pawns to 48 pawns very quickly, SF has seen mate.
So why isn't it reporting a mate-score, then?
what if SF has pruned above position, because its counter says 50-moves threshold, draw, to the benefit of this one
The position is not a 50 move draw, so if it had done that there's a bug to fix.
You also seem to confuse "pruning" with returning the known evaluation (and stopping the search) in tablebase positions.
I specifically said 'during the search', but you seem not to read.
You don't understand.
As soon as you capture into a 5-man position you access the tablebase. The capture, of course, reset the 50-move counter. The situation you scetch never occurs because the search never probes the tablebase excpt when the 50-move counter is 0.
rigth, I missed the fact that, in order to arrive at a tbs position, the last move should be a capture.

essentially this changes nothing though, you just have to use tbs mates that go over the 50-move counter.

looking at TCEC, SF shows frequently more than 30 000 000 tbs hits, if 1% of those are so called "cursed wins", this makes 300 000 cursed win hits. Imagine the impact on search decisions, gameplay and picking the best move.

Lyudmil Tsvetkov
Posts: 6031
Joined: Tue Jun 12, 2012 10:41 am

Re: fortress_draw_rule

Post by Lyudmil Tsvetkov » Fri Nov 25, 2016 8:41 am

syzygy wrote:
Lyudmil Tsvetkov wrote:I specifically said 'during the search', but you seem not to read.

above position could be encountered by the engine at depth 20 (43+10=53>50) during search, and the tbs will instruct it it needs 43 moves more to mate, going over the 50-move threshold, so it will conisder it as a draw.
The only way to reach this position "during the search" is by a capture from 6 to 5 pieces. The capture resets the 50-move counter. So a probe during the search only needs to check whether the position is won with DTZ <= 100 ply.
as a result, the engine will lose half a point with no reason at all; by choosing the other node it goes for its 'best' move, which actually is suboptimal to the tbs position, and results only in a draw.
No, you are simply talking about a topic you don't understand very well.
rigth, the last move must be a capture.

essentially, what changes this though? any tbs mate longer than 50 moves will be considered as a draw, this node will return a score of 0.0, while another node, with no tbs hits and a score of, say 40cps, objectively a draw in the eg, will be considered by the engine stronger than the 0.0 cursed win node.

this definitely has implications on choosing the best move. why consider a node that is draw with slightly positive score better than a node with 0.0 score, objectively though a win?

during search, an engine might hit hundreds of thousands similar cursed win nodes, and take decisions accordingly. the impact on game play should not be small.

Milos
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Re: fortress_draw_rule

Post by Milos » Fri Nov 25, 2016 8:44 am

Lyudmil Tsvetkov wrote:looking at TCEC, SF shows frequently more than 30 000 000 tbs hits, if 1% of those are so called "cursed wins", this makes 300 000 cursed win hits. Imagine the impact on search decisions, gameplay and picking the best move.
Stop trolling and behaving retarded when you are not.
0% (and in words ZERO) of TB hits are cursed wins for SF or H. Reason is, they have correct TBs implemented that respect the rules of chess i.e. 50 moves rule.
Claiming to have an imaginary win based on some crappy TBs output is like requesting from the referee in FIDE match to adjudicate win in some position just because you announced mate in N (>50) moves claiming there is a win and you know it without any intentions to actually demonstrate it. Try doing it in official match and tell us your experiences. I bet you'd be laughed like hell and ppl would think you've gonne crazy.

Lyudmil Tsvetkov
Posts: 6031
Joined: Tue Jun 12, 2012 10:41 am

Re: fortress_draw_rule

Post by Lyudmil Tsvetkov » Fri Nov 25, 2016 8:51 am

syzygy wrote:
Evert wrote:
Lyudmil Tsvetkov wrote:[d]8/4n3/4k3/8/8/4K1B1/2B5/8 w - - 0 1

why instruct the engine above position is a draw, when SF finds mate very quickly even at bullet?
I'm not sure what point you think you're making?
The position is apparently mate in 43 moves (starting with 1. Bb3+), so the 50 move rule is irrelevant even if the knight is not captured (which I haven't checked). Source: Nalimov tables from http://www.k4it.de/?topic=egtb&lang=en.
Yes, one side to this discussion is rather unwilling to understand the stuff he's talking about.

https://syzygy-tables.info/?fen=8/4n3/4 ... _w_-_-_0_1

DTZ=59, so white can force a mate or winning capture in under 30 moves.

If this were impossible to win within the 50-move rule, SF would be expected not to find a mate in the first place. After all, SF knows about and accepts the 50-move rule.
I can not go check each and every tbs position whether is a longer or shorter than 50 mate. The general rule say BB vs N 66 moves longest mate, there are shorter mates of course. the point was to demonstrate that SF is able to deliver mate on its own in such positions, so why deprive it of a well-deserved win?

do not have quick access as well as the time to check tbs now, I hope you will help out with this, but here is a position I presume is longer than 50 mate:

[d]2kb4/1b6/8/8/3Q4/8/8/4K3 w - - 0 1

actually, a variation of the TCEC game

I presume SF will be able to deliver mate on its own above at blitz TC, will it not?

Is somebody able to check this?

duncan
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Joined: Mon Jul 07, 2008 8:50 pm

Re: fortress_draw_rule

Post by duncan » Fri Nov 25, 2016 9:30 am

Lyudmil Tsvetkov wrote: do not have quick access as well as the time to check tbs now, I hope you will help out with this, but here is a position I presume is longer than 50 mate:

[d]2kb4/1b6/8/8/3Q4/8/8/4K3 w - - 0 1

actually, a variation of the TCEC game

I presume SF will be able to deliver mate on its own above at blitz TC, will it not?

Is somebody able to check this?
qd4 -d6 win in 31

Joerg Oster
Posts: 609
Joined: Fri Mar 10, 2006 3:29 pm
Location: Germany

Re: fortress_draw_rule

Post by Joerg Oster » Fri Nov 25, 2016 10:26 am

Lyudmil Tsvetkov wrote:
syzygy wrote:
Evert wrote:
Lyudmil Tsvetkov wrote:[d]8/4n3/4k3/8/8/4K1B1/2B5/8 w - - 0 1

why instruct the engine above position is a draw, when SF finds mate very quickly even at bullet?
I'm not sure what point you think you're making?
The position is apparently mate in 43 moves (starting with 1. Bb3+), so the 50 move rule is irrelevant even if the knight is not captured (which I haven't checked). Source: Nalimov tables from http://www.k4it.de/?topic=egtb&lang=en.
Yes, one side to this discussion is rather unwilling to understand the stuff he's talking about.

https://syzygy-tables.info/?fen=8/4n3/4 ... _w_-_-_0_1

DTZ=59, so white can force a mate or winning capture in under 30 moves.

If this were impossible to win within the 50-move rule, SF would be expected not to find a mate in the first place. After all, SF knows about and accepts the 50-move rule.
I can not go check each and every tbs position whether is a longer or shorter than 50 mate. The general rule say BB vs N 66 moves longest mate, there are shorter mates of course. the point was to demonstrate that SF is able to deliver mate on its own in such positions, so why deprive it of a well-deserved win?

do not have quick access as well as the time to check tbs now, I hope you will help out with this, but here is a position I presume is longer than 50 mate:

[d]2kb4/1b6/8/8/3Q4/8/8/4K3 w - - 0 1

actually, a variation of the TCEC game

I presume SF will be able to deliver mate on its own above at blitz TC, will it not?

Is somebody able to check this?
Why don't you check yourself? :D

Here https://syzygy-tables.info/ you can insert the FEN of the position you want to know,
and you get all information you need.

You can even download the full PGN of the main dtz winning line.

Code: Select all

&#91;Event ""&#93;
&#91;Site "http&#58;//syzygy-tables.info/?fen=2kb4/1b6/8/8/3Q4/8/8/4K3_w_-_-_0_1"&#93;
&#91;Date "2016.11.25"&#93;
&#91;White "Syzygy"&#93;
&#91;Black "Syzygy"&#93;
&#91;Result "1-0"&#93;
&#91;SetUp "1"&#93;
&#91;FEN "2kb4/1b6/8/8/3Q4/8/8/4K3 w - - 0 1"&#93;
&#91;Annotator "syzygy-tables.info"&#93;

&#123; DTZ 43 &#125; 1. Qd6 Bc7 2. Qe6+ Kd8 3. Kd2 Bc8 4. Qc6 Bd7 5. Qf6+ Kc8 6. Kc3 Kb7 7. Kc4 Bb6 8. Kd5 Bb5 9. Qe7+ Ka6 10. Kd6 Ba7 11. Kc7 Bb6+ 12. Kb8 Bc4 13. Qb4 Bb5 14. Qa3+ Ba5 15. Qb3 Bb6 16. Qa2+ Ba5 17. Qd5 Bb4 18. Qb7+ Ka5 19. Qa7+ Ba6 20. Kc7 Kb5 21. Qb6+ Ka4 22. Qxa6+ &#123; KQvKB with DTZ -16 &#125; 22... Kb3 23. Qd3+ Kb2 24. Kb6 Bc3 25. Kb5 Kb3 26. Kc5 Kb2 27. Kc4 Ba5 28. Qb3+ Ka1 29. Qa3+ Kb1 30. Qxa5 &#123; KQvK with DTZ -6 &#125; 30... Kb2 31. Qd2+ Ka1 32. Kb3 Kb1 33. Qb2# &#123; Checkmate &#125; 1-0
Jörg Oster

Lyudmil Tsvetkov
Posts: 6031
Joined: Tue Jun 12, 2012 10:41 am

Re: fortress_draw_rule

Post by Lyudmil Tsvetkov » Fri Nov 25, 2016 11:15 am

Milos wrote:
Lyudmil Tsvetkov wrote:looking at TCEC, SF shows frequently more than 30 000 000 tbs hits, if 1% of those are so called "cursed wins", this makes 300 000 cursed win hits. Imagine the impact on search decisions, gameplay and picking the best move.
Stop trolling and behaving retarded when you are not.
0% (and in words ZERO) of TB hits are cursed wins for SF or H. Reason is, they have correct TBs implemented that respect the rules of chess i.e. 50 moves rule.
Claiming to have an imaginary win based on some crappy TBs output is like requesting from the referee in FIDE match to adjudicate win in some position just because you announced mate in N (>50) moves claiming there is a win and you know it without any intentions to actually demonstrate it. Try doing it in official match and tell us your experiences. I bet you'd be laughed like hell and ppl would think you've gonne crazy.
for reference, "cursed win" is a definition for this type of positions, coming from Ronald's SF tablebase code. (I do not know if it is also a more general term)

so, SF him/her/itself (another retarded manifestation) regards such tbs positions as "cursed wins", it was not my invention of any sort.

if you want to help, just tell us, is SF able to win the Q vs 2 bishops tbs position I posted, or not. That would be of conisderable help for the discussion, labelling on the other hand is not.

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hgm
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Location: Amsterdam
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Re: fortress_draw_rule

Post by hgm » Fri Nov 25, 2016 11:23 am

Well, Duncan already posted that it is a mate in 31. So what else do you need to make yourself look foolish?

Lyudmil Tsvetkov
Posts: 6031
Joined: Tue Jun 12, 2012 10:41 am

Re: fortress_draw_rule

Post by Lyudmil Tsvetkov » Fri Nov 25, 2016 11:26 am

Joerg Oster wrote:
Lyudmil Tsvetkov wrote:
syzygy wrote:
Evert wrote:
Lyudmil Tsvetkov wrote:[d]8/4n3/4k3/8/8/4K1B1/2B5/8 w - - 0 1

why instruct the engine above position is a draw, when SF finds mate very quickly even at bullet?
I'm not sure what point you think you're making?
The position is apparently mate in 43 moves (starting with 1. Bb3+), so the 50 move rule is irrelevant even if the knight is not captured (which I haven't checked). Source: Nalimov tables from http://www.k4it.de/?topic=egtb&lang=en.
Yes, one side to this discussion is rather unwilling to understand the stuff he's talking about.

https://syzygy-tables.info/?fen=8/4n3/4 ... _w_-_-_0_1

DTZ=59, so white can force a mate or winning capture in under 30 moves.

If this were impossible to win within the 50-move rule, SF would be expected not to find a mate in the first place. After all, SF knows about and accepts the 50-move rule.
I can not go check each and every tbs position whether is a longer or shorter than 50 mate. The general rule say BB vs N 66 moves longest mate, there are shorter mates of course. the point was to demonstrate that SF is able to deliver mate on its own in such positions, so why deprive it of a well-deserved win?

do not have quick access as well as the time to check tbs now, I hope you will help out with this, but here is a position I presume is longer than 50 mate:

[d]2kb4/1b6/8/8/3Q4/8/8/4K3 w - - 0 1

actually, a variation of the TCEC game

I presume SF will be able to deliver mate on its own above at blitz TC, will it not?

Is somebody able to check this?
Why don't you check yourself? :D

Here https://syzygy-tables.info/ you can insert the FEN of the position you want to know,
and you get all information you need.

You can even download the full PGN of the main dtz winning line.

Code: Select all

&#91;Event ""&#93;
&#91;Site "http&#58;//syzygy-tables.info/?fen=2kb4/1b6/8/8/3Q4/8/8/4K3_w_-_-_0_1"&#93;
&#91;Date "2016.11.25"&#93;
&#91;White "Syzygy"&#93;
&#91;Black "Syzygy"&#93;
&#91;Result "1-0"&#93;
&#91;SetUp "1"&#93;
&#91;FEN "2kb4/1b6/8/8/3Q4/8/8/4K3 w - - 0 1"&#93;
&#91;Annotator "syzygy-tables.info"&#93;

&#123; DTZ 43 &#125; 1. Qd6 Bc7 2. Qe6+ Kd8 3. Kd2 Bc8 4. Qc6 Bd7 5. Qf6+ Kc8 6. Kc3 Kb7 7. Kc4 Bb6 8. Kd5 Bb5 9. Qe7+ Ka6 10. Kd6 Ba7 11. Kc7 Bb6+ 12. Kb8 Bc4 13. Qb4 Bb5 14. Qa3+ Ba5 15. Qb3 Bb6 16. Qa2+ Ba5 17. Qd5 Bb4 18. Qb7+ Ka5 19. Qa7+ Ba6 20. Kc7 Kb5 21. Qb6+ Ka4 22. Qxa6+ &#123; KQvKB with DTZ -16 &#125; 22... Kb3 23. Qd3+ Kb2 24. Kb6 Bc3 25. Kb5 Kb3 26. Kc5 Kb2 27. Kc4 Ba5 28. Qb3+ Ka1 29. Qa3+ Kb1 30. Qxa5 &#123; KQvK with DTZ -6 &#125; 30... Kb2 31. Qd2+ Ka1 32. Kb3 Kb1 33. Qb2# &#123; Checkmate &#125; 1-0
thanks Joerg.

because in that case there will be no one to ask questions and suggest new rules... :(

I have another request for you or anyone else capable of helping:

[d]K5Q1/8/8/8/5bb1/6k1/8/8 w - - 0 1

this already should be tbs win in more than 50.

is SF able to deliver mate in blitz mode without tbs?

Lyudmil Tsvetkov
Posts: 6031
Joined: Tue Jun 12, 2012 10:41 am

Re: fortress_draw_rule

Post by Lyudmil Tsvetkov » Fri Nov 25, 2016 11:35 am

hgm wrote:Well, Duncan already posted that it is a mate in 31. So what else do you need to make yourself look foolish?
getting a reply from Duncan, and asking Milos the same thing, to acknowledge SF is able to mate easily, are 2 different things.

besides, I did not ask if it is mate, but whether SF is able to deliver the mate without tbs. also 2 different things.

sometimes people are also in a hurry and post, before reading the whole thread.

the point is, if SF is able to mate below:

[d]K5Q1/8/8/8/5bb1/6k1/8/8 w - - 0 1

why adjudicate draw? why on Earth?

that is the real question, and not whether I have posted a mate shorter than 50 instead of a longer one. I guess everyone understands that.

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