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MatPlus.Net Forum General New ideas for solvers in Ohrid
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(1) Posted by Andrey Selivanov [Tuesday, Sep 11, 2018 20:15]

New ideas for solvers in Ohrid

An interesting novelty was applied by the Director of 42th the world championship in Ohrid. In a H#5.5 speed instead of the 3 solutions was actually 4 solutions. This result gives any program for the solution.
I think that such a problem cannot participate in competitions and it should be excluded.
Интересную новинку применил директор чемпионата мира по решению в Охриде. В кооперативном мате в 5,5 хода вместо 3 решений, на самом деле было 4 решения. Такой результат дает любая программа для решения. Я думаю, что такая задача не может участвовать в соревнованиях и она должна быть исключена.
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(2) Posted by Nikola Predrag [Tuesday, Sep 11, 2018 22:36]

Andrey, computer is only a helpful machine. Human mind is relevant for the interpretation of the computer's result.
For the correct interpretation we should apply the rules. I hope the Codex is clear about that h#5.5.
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(3) Posted by Andrey Selivanov [Wednesday, Sep 12, 2018 03:37]; edited by Andrey Selivanov [18-09-12]

Yes. Nikola!
"The selected problems should show a clear theme and a good level of quality and difficulty".
Solution in H$5,5 a) 1...Tg3+ 2.Kh1 c4 3.Ld4 cxd5 4.Lg1 dxc6 5.Tb7+ cxb7 6.Lh2 bxa8=D,L#
Meet the criteria of the codex? is it one or 2 solutions?
a1) 1...Tg3+ 2.Kh1 c4 3.Ld4 cxd5 4.Lg1 dxc6 5.Tb7+ cxb7 6.Lh2 bxa8=D#
a2) 1...Tg3+ 2.Kh1 c4 3.Ld4 cxd5 4.Lg1 dxc6 5.Tb7+ cxb7 6.Lh2 bxa8=L#
If it's a dual, then the solution is not clean.
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(4) Posted by Kostas Prentos [Wednesday, Sep 12, 2018 07:59]

Article 13 of the Codex (about Unsound Chess Compositions), paragraph 2 is as follows:

Help-play compositions are unsound also if they are dualized, except that in the final move a promotion into different pieces having partially the same power (for example queen/rook or queen/bishop) may be tolerated.

So, this dual may be tolerated, but the tolerance level is different for each one of us. Personally, I would avoid it by all means in my own compositions, but others might not. However, I would not count this dual as a new solution, as Andrey suggests. So, imho, the problem in question has 3 solutions, not 4. If the dual can be tolerated in composing tourneys, then it can certainly be tolerated in solving tourneys, despite the rules to solving directors.
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(5) Posted by Andrey Selivanov [Wednesday, Sep 12, 2018 08:49]

Yes, when composing a problem, such a dual is allowed, but does not add quality to the content of the problem. And in solving competitions the Director shouldn't give such problems!
For example, the solver will indicate two such solutions.
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(6) Posted by Nikola Predrag [Wednesday, Sep 12, 2018 10:31]

The point is that the "opinion" of a solving program IS NOT acceptable as an argument. Program can't understand that it is ONLY ONE SOLUTION with a dual.
Does anyone (human) think seriously that Loyd's Excelsior has two main variations (one ending 5.bxa8Q#? and the other 5.bxa8B#)?

But indeed, in some tourneys, there have been much bigger troubles with the quality of problems for solving, especially with studies.
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(7) Posted by Georgy Evseev [Wednesday, Sep 12, 2018 12:44]

Fortunately, the problem in question had twins, which generally makes the current dispute meaningless.
Nevertheless, I agree that such problems should be avoided.

There is also another issue: are twins really allowed?

I am not sure that they satisfy the following rules paragraph:
7.1. The problems to be solved must be presented on printed diagrams.
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(8) Posted by Juraj Lörinc [Wednesday, Sep 12, 2018 19:42]

I see plague of literally literal reading of rules has already spread from some legal systems to chess composition. Well, unless some of the questions posed are meant as irony...
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(9) Posted by Georgy Evseev [Thursday, Sep 13, 2018 07:13]

Juraj, if you refer to my post, then I am deadly serious.

My personal experience shows, that any written rule must be fully detailed and applied literally. Any ambiguity or implicit meaning may resurface at the worst moment with the worst consequences.
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(10) Posted by David [Thursday, Sep 13, 2018 16:11]; edited by David [18-09-13]

Rules? Rules! Rules... :) I think that there are no rules in W(E)CSC at all, but there are people who think up and interpret them depending on how it is beneficial for themselves or as they want.
For example, how much times "The Rules..." were broken in the last WCSC? Who counts more?
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(11) Posted by Juraj Lörinc [Thursday, Sep 13, 2018 21:01]

@Georgy: yes, your post #7 has prompted me to express my worries.

The problem with twins is printed as a whole, including description of the twin. Even if it is only symbolic, it is clear to anyone participating and it is printed.

If you insisted that every single position from the twin problem has to be printed separately, then you should probably insist on the whole wording of the stipulation and requirements from solvers printed (like: instead of "#2" there should be something like "White makes the first move and then mates regardless of the black defence. Write only key." - because this is exaclty what is requested from solvers - and maybe "key" is not a right word as it would require further explanations. And maybe the movement of pieces associated with symbols on the printed diagrams should be given too, in case somebody does not know it...) These all details are missing from printed sheets of the WCSC first rounds, aren't they?

I am exaggerating, obviously. But I mistily remember some participants in serious competitions that were puzzled by h#2 stipulation...
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(12) Posted by Georgy Evseev [Friday, Sep 14, 2018 11:29]


WCSC/ECSC are the competitions where we have written rules. From my point of view, such rules should be followed literally or it gives any solver potential reason to protest, like: Show me the printed diagram of the problem marked b) here.
And there is also another, not so obvious issue with twins. When you are solving the problem with several solutions, you are searching for any solution. With twins you are searching for specific solution in each twin which may be more difficult to find, especially when when the solutions are loosely connected (or even fully unconnected). Several conclusions may follow.

In fact, I did not insist on any specific changes. But I am sure that the solver who wants to interpret the rules literally should be able to do so, not seeing any contradictions to the rules and or suspicious decisions from director. The easiest change (concerning this issue, if the twins are accepted) should probably be the mention that twins may be allowed and only one diagram is enough in this case. (In fact, I am still waiting for nightmare of having three twomovers with 3-5 twins each in the first round. The current rules easily allow it.)

And moreover, current rules do not have the definition what correct solution is. This issue resurfaces from time to time in cases of problems with multiple threats, branching variations, duals, director's misprints, etc. Each such case is still resolved manually (and as a result often in different way). It looks like nobody sees this issues or is interested in resolving them (maybe, until next big scandal/conflict).
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(13) Posted by Miodrag Mladenović [Friday, Sep 14, 2018 11:34]

I do agree with Georgy completely. I believe that twins should be forbidden (in any round). The twins are increasing the number of problems without adding additional times. With a multiple solutions you do look same position for different solutions. With a twins there are two issues:

1) You can not solve problem from the diagram
2) You are looking into completely different positions and very often solutions are not analogue at all.

In my opinion we should not allow twins.
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MatPlus.Net Forum General New ideas for solvers in Ohrid