3 Champs Highlights

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Lyudmil Tsvetkov
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3 Champs Highlights

Post by Lyudmil Tsvetkov » Thu Aug 29, 2013 7:52 am

I might post here a couple of intriguing positions from Clemens' 3Champs tournament.

The setup is great, there are some very interesting games, and it would be a sin not to comment a bit on it.

If someone would like to comment, contribute with engine analysis, refutations, etc., I would be only extremely happy, but even if not so, I will give my humble comments to a couple of games. I see in CSS Kurt (Utzinger) complaining about the lack of feedback on his posts about, for example, the Alekhine-Capablanca match, and I understand Kurt, but I know, that even if no one replies, someone still might be reading this, so it is not totally devoid of meaning. If one person reads this thread, I would still be happy.

And you never know, someone might contribute with a reply though :D

Best, Lyudmil

Lyudmil Tsvetkov
Posts: 6052
Joined: Tue Jun 12, 2012 10:41 am

The Pawn-eater

Post by Lyudmil Tsvetkov » Thu Aug 29, 2013 8:11 am

[D]1r2r1k1/1pn2p1p/2pb1qp1/p4p2/3P4/1QP3P1/PP3PBP/R1B2RK1 w - - 0 17

This is a position from the 57th game of the tournament.

Stockfish has played very well the opening with white against Houdini, but now decides to attack and eat with the queen an enemy pawn far from where the main battle takes place. Stockfish plays now 17.Qa4, upon which Houdini replies with 17...f4, takes the initiative and builds up a devastating king attack.

I think Stockfish could easily keep some edge by playing 17.f4 itself instead, depriving black of any attacking opportunities and using its majority pawn on the queen side, when the time is favourable for that. I think playing 17.f4 is a must in this position, even if black did not threaten with a very menacing attack, because this move would be very helpful in the long term: it fixes (blocks) the most advanced black double pawn (f5) with an own pawn, and that is a serious advantage, long-term at that, that should be worth some 10-15cps. In this way the weakness of the double pawn becomes difficult or almost impossible to straighten, and that is always a positional asset. I think that whenever a real possibility to block with an own pawn the most advanced enemy double pawn exists, such a move should enjoy priority status, because a move or 2 later it could already not be playable, thus missing a valuable positional edge.

Of course, white might have been afraid that f4 would leave the e3 square undefended, but that is much less important in this particular case.

Any engines there willing to play 17.f4?

Best, Lyudmil

Lyudmil Tsvetkov
Posts: 6052
Joined: Tue Jun 12, 2012 10:41 am

Grandmaster draw

Post by Lyudmil Tsvetkov » Thu Aug 29, 2013 8:34 am

This might be a bit off-topic, but, as I am observing very frequently such a behaviour, I decided to raise the issue.

[D]8/3b4/5kpp/8/6P1/4P3/4B3/4K3 w - - 0 67
This is a position from the 53rd game, pitting Komodo with white against Houdini. The position is obviously a draw, no possibilities whatever for a win for one of the sides, but both players trudge on heroically with this endgame for 40 more moves until finally, exhausted by the fervent battle, they agree to a draw at move 106.

[D]4b3/8/7K/8/6B1/4P3/3k4/8 b - - 0 106

Here the engines agree to a draw.

My question to all forumers, experts, possibly authors, is whether such a rather consistent behaviour of leading and non-leading engines is necessary and justified. Of course, I understand there are positions in which you should press on, but there are also some very simple, very obviously drawish positions whose martyrisation could very well be avoided.

It is really a pity, especially for the public watching the event, that some meaningless shuffling should become the center-piece of attention for quite some time. I could even call it the Ponomaryov syndrome, playing until your last pawn, but I think it is even worse than that, because modern engines are supposed to be very sophisticated, and they indeed are in a wide range of fields; however, for me, here they fail. It is not very much grandmasterly at all, really, to observe such a behaviour or be the mastermind behind it.

Any suggestions what could be done to avoid similar behaviour of engines?

Best, Lyudmil

Lyudmil Tsvetkov
Posts: 6052
Joined: Tue Jun 12, 2012 10:41 am

I like it

Post by Lyudmil Tsvetkov » Thu Aug 29, 2013 10:40 am

[D]r1b1r1k1/1pb2q2/2p1pn2/3p3p/PBPPp1p1/1Q2P1P1/P1RNNP1P/5RK1 b - - 0 21

This is a position from the 46th game Stockfish-Komodo.

Stockfish has just played 21.g3 and sees itself in advantage by some 0.74 centipawns, very decisive one, while Komodo thinks it is about equal.

Objectively, I think the position is already won for black, because of the following reasons:

- very weak backward (backward-fated) white pawn on f2, part of the king shelter; that makes the shelter very inflexible and black can gradually concentrate attacking resources
- 2 weak squares on the 3rd rank, part of the king shelter (f3 and h3), whereupon different enemy pieces, especially the knight, might intrude
- play is more or less closed, because of the big diagonally connected pawn chains, which gives black sufficient time to prepare a decisive strike

Black has some difficulties with developing its queen side, but I think those could be solved and are less weighty than the above-mentioned serious weaknesses of the white king shelter.

I tell you, I like this position, because it is a bit uncommon and also rich in resources that should be sought out. I could suggest a plan like, for example, Nh7-g5, Kh7, Rh8, Kg8, and only then h4, if necessary, prepare for e5 and bring the a rook in support of the attack, etc. In that case it is difficult to imagine how white could defend.

Komodo, however, proceeds to lose the already won game in just 2 moves by playing h5-h4-h3 instead, closing entirely the side where it is supposed to open files for attack.

[D]r1b1r1k1/1pb2q2/2p1pn2/3p4/PBPPp1p1/Q3P1Pp/P1RNNP1P/5RK1 w - - 0 23

This is the picture 2 moves later, where already white is lost. Black has a single semi-open file at its disposal (f), but both f2 and f3 are well guarded, white can also play Nf4, blocking this file to good avail, etc. It takes Komodo, however, some 60 moves to understand it is losing; and the same amount of moves it takes Stockfish to find a way to finally break through, but it does it in great fashion. When I think about that, it makes me happy that it is not only me that can lose games in 2 moves, but also Komodo can do that. If Komodo can do that, I have the right to do it too :)

[D]r1b1r1k1/1pb2q2/2p1pn2/3p4/PBPPpNp1/Q3P1Pp/P1RN1P1P/5RK1 b - - 0 23

I think black should have attempted to play e5 here, whatever the result, there is simply no other option.

[D]k1N5/1p4R1/rP2p3/P1PpB2q/PQ2p3/4Pp1p/5P1P/7K b - - 0 101

But I do not like this: a Ponomaryov-style Komodo playing until the very last glimmer of hope.

Finally, let's go back for a while to the main diagram:

[D]r1b1r1k1/1pb2q2/2p1pn2/3p3p/PBPPp1p1/1Q2P1P1/P1RNNP1P/5RK1 b - - 0 21

Komodo played very well until now, both g5 and g4 are great moves, but the point is: how many engines will be able to judge correctly that black has a considerable, probably winning advantage, and to find the correct winning way?

Any distinct engine output on this position very much appreciated.

Best, Lyudmil

Lyudmil Tsvetkov
Posts: 6052
Joined: Tue Jun 12, 2012 10:41 am

Re: I like it

Post by Lyudmil Tsvetkov » Thu Aug 29, 2013 11:24 am

Again, I think black has a very clear plan here, while white can do basically nothing during this time: Nh7-g5, Kg7, Rh8-h6, Rb8, Bd7, h4, Rbh8 and it is difficult to believe there could be more than one outcome.

Also, it is worth noting that Komodo could have achieved that setup without sacrificing a pawn on a4 and consequently exposing its queen side to attack.

But again, engines that rely only on open, semi-open files, mobility, etc., will never judge the position as won for black. On the other hand, engines that use also in their eval concepts like different types of chains, weak squares (undefended by pawns) part of the king shelter, backward-fated pawns part of the king shelter, etc., will quickly judge the position as easily won for black. Where there is nothing specific, you have to rely on eval, and when the eval is wrong or imperfect, you will consequently have wrong or imperfect results.

PS. Again, nothing bad meant for engines, just some hallucinatory remarks. :( Any harsh words addressed to me very much welcome.

Lyudmil Tsvetkov
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Do I have a storming pawn?

Post by Lyudmil Tsvetkov » Thu Aug 29, 2013 11:49 am

[D]2r3k1/p2b1pp1/1r2p2p/p1qpP3/P2N1P2/1PP2R2/2Q3PP/2R3K1 w - - 0 25

This is a position from the 55th game, pitting Komodo (white) against Stockfish.

Stockfish played a bad opening, unnecessarily doubled and isolated its a pawns for a semi-open file that brings almost nothing, and komodo actually manages to win the game convincingly in the late endgame. But my sollicitude is that in the above position white does not find a much quicker winning way, starting with the advance of a storming pawn, namely 25.g4.

I think the ambient is already prepared for such a push, as black could do nothing on the queen side, so formidable is the liability of the double horizontally isolated pawns plus the white asset of the excellent d4 knight versus the somewhat 'bad' black bishop. After g4, Rg3 with doubling or trebling of heavy pieces along the g file could follow, then h4, and either h5, g5 or f5, depending on circumstances, with a crushing attack.

I wonder why white is unable to see that 25.g4 is an excellent move, and plays h3 5 moves later, depriving its heavy pieces of the use of the h file, and only 15 moves later, but in quite a different setting, g4 starts deciding the game. Is that, actually, engines do not consider bonus points for storming pawns on the 4th rank (because I have observed such behaviour with most engines), starting with the 5th instead, or maybe there are some other reasons?

Anyway, any feedback would be very much appreciated.

PS. And again, this is not supposed to be criticising; it is just some curious topics that have been picked up. If you convince me that g4 is a bad move, I am ready to take my words back.

Lyudmil Tsvetkov
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Re: Grandmaster draw

Post by Lyudmil Tsvetkov » Thu Aug 29, 2013 3:05 pm

My suggestion for avoiding dull drawish positions might run somewhere along the following lines:

- both sides have only 2 pawns or less
- score is within the range 0.0-0.40
- both sides have only 2 minor pieces at most, or one rook at most, or just a queen,

then a draw agreement should follow very soon, probably in a couple of moves' time, if none of the above factors changes in the meantime.

I think avoiding dull drawish lines and consenting to a grandmaster draw instead would only enhance the quality and attractiveness of computer chess, but also save some testing time.

Btw., and this already might intrigue some people, in sharp distinction to the things said above, according to my rough assessments, such dull positions might constitute, at least with Clemens settings, some 1/4 to 1/3 of all executed moves, and probably a similar amount of time. But even if they take up just 1/5 of testing time, could someone do the maths how many additional meaningful testing games could be run when this amount of time is freed up, especially when large quantity of games are played? And when you factor in that also the additionally played games will last shorter.

I think scrapping in one or another way dull drawish positions definitely hides some opportunities.

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

Re: I like it

Post by Lyudmil Tsvetkov » Thu Aug 29, 2013 3:14 pm

And once again, I think factors like backward pawns part of the king shelter, or weak squares part of the king shelter should make up a necessary part of king safety eval.

Considering only terms like number of pawns around the king, or placement of the king might really be very rudimentary for a sophisticated state-of-the-art software.

Just my 2 cents.

tpetzke
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Re: Do I have a storming pawn?

Post by tpetzke » Thu Aug 29, 2013 3:17 pm

Hi,

I have no insights into Komodos eval but if he would consider a White pawn at g5 in this position good it would have no trouble finding g4 even if the bonus is not applied with a pawn on the 4th rank already. That is how search works.

In my engines eval I award a bonus for a pawn storm mainly in positions where the kings have castled to opposite sides.

So I discourage pawns from advancing if they are part of the own king shelter. If the penalty for a weaker shelter is higher than the bonus for a storming pawn the pawn will not be moved.
Thomas...

=======
http://macechess.blogspot.com - iCE Chess Engine

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Don
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Re: Grandmaster draw

Post by Don » Thu Aug 29, 2013 3:28 pm

Lyudmil Tsvetkov wrote:This might be a bit off-topic, but, as I am observing very frequently such a behaviour, I decided to raise the issue.

[D]8/3b4/5kpp/8/6P1/4P3/4B3/4K3 w - - 0 67
This is a position from the 53rd game, pitting Komodo with white against Houdini. The position is obviously a draw, no possibilities whatever for a win for one of the sides, but both players trudge on heroically with this endgame for 40 more moves until finally, exhausted by the fervent battle, they agree to a draw at move 106.

[D]4b3/8/7K/8/6B1/4P3/3k4/8 b - - 0 106

Here the engines agree to a draw.

My question to all forumers, experts, possibly authors, is whether such a rather consistent behaviour of leading and non-leading engines is necessary and justified. Of course, I understand there are positions in which you should press on, but there are also some very simple, very obviously drawish positions whose martyrisation could very well be avoided.

It is really a pity, especially for the public watching the event, that some meaningless shuffling should become the center-piece of attention for quite some time. I could even call it the Ponomaryov syndrome, playing until your last pawn, but I think it is even worse than that, because modern engines are supposed to be very sophisticated, and they indeed are in a wide range of fields; however, for me, here they fail. It is not very much grandmasterly at all, really, to observe such a behaviour or be the mastermind behind it.

Any suggestions what could be done to avoid similar behaviour of engines?

Best, Lyudmil
Very often both programs KNOW it's a draw but there is no provision in most chess software for 2 programs to agree to a draw between themselves. You would have to be able to propose and also accept or reject the proposal. So humans often make the adjudication decisions. Such a protocol thing could be added and it would help in some of these positions. (**) Why would you expect a computer to stop playing without being instructed to stop?

Even if such a protocol was instituted there are clearly some positions which computers do not understand to the point of knowing it's a dead draw. They might play them correctly but not understand. That is because at the current time chess programs do not do chains of reasoning like humans do. For example a computer will never reason like this:

1. I cannot win because I have only a knight
2. My opponent has a knight and pawn.
3. I cannot hope to win, only draw.
4. I must stop that pawn and it's ok to SAC my knight to do it

Most programs KNOW that a lone knight is a draw so they will SAC their knight in this situation, but not because they reasoned it out like the above - only because they were given a rule about the specific values of the configurations.

Bishop of opposite color when trivially drawn is easy to spot because a human can sweep the board with his eyes and apply a "general case" to potentially dozens of positions. Computers simply cannot do that - or at least cannot do that now. So we just tell them that if you have bishops of opposite color the advantage of an extra pawn or two is LESS. We cannot even reliably specify exactly when it's a draw and when it's not.

Another example is locked pawn draws. You can be up a queen and a win is impossible and a human can see this at a glance. It's actually more non-trivial than you think to create rules which cover situations that are intuitive to a human and never go wrong. For example determining if a locked pawn is a draw is possible but you have to cover a bunch of things such as can something like a knight pass to the opponent side? Is a sacrifice possible to break the lock? Even knowing which side of the locked pawn structure a piece is has to be explicitly coded even though humans see it at a glance. It's not as simple as just saying, "on the opponents half of the board." Sometimes there are holes (the pawns are rammed but not connected) but a king still cannot pass through - or maybe it can and it's still an obvious draw - so all of these cases have to be explicitly coded.

So even the relatively simple case of fully locked pawns - is only "relatively" simple, requiring several checks to avoid being pathologically wrong. And then it comes down to whether it is a true benefit. There will be a speed penalty for any knowledge added. I made a rule that said if there are 8 pawns and they are locked together AND also connected then consider the position very drawish (multiple the score by something like 0.10
or so) and after 50,000 games it came out slightly weaker. This is such a rare corner case that it was not measurable - and perhaps it was even wrong in some cases. However it WAS able to solve positions like QxP (giving up the queen) to break open the pawn structure when it was ahead in material. It LOOKED very impressive in hand-picked situations.

In some ways you remind me of the early days of computer chess, it's like you are noticing things for the first time that seem like major insights to you but we knew about 30 years ago. That's ok - we have never stopped thinking about them and we still listen on the off chance that you will propose a solution instead of just reiterating the problem. We know the problem, please give us a solution.
Capital punishment would be more effective as a preventive measure if it were administered prior to the crime.

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