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MatPlus.Net Forum Competitions Jurmala Internet Tourney 2024 - #2

### Jurmala Internet Tourney 2024 - #2

It asks for the pattern that have been realized at least a dozen times,
but probably never discriminated as a separate theme:
The section for entering entries directly into MatPlus/Originals/Jurmala IT 2024 will be created soon.
Your feedback, including possible earlier examples and all the questions will be most welcome!

marjan, this looks quite unconventional and interesting!

just please clarify the "~" symbol in the provided tables:
a) what can it be?
b) what must it not be?

Thanks, Peter!
I used the sign "~" as "whatever" but now I see it should be explained better.

a1) Variations in the empty squares may physically not exist, as in Example 1.

a2) There may be no mates there, as after 1...Kxc5 & 1...Rxe5 in the set-play of Example 2

a3) There may be some new mates there, as 1...Kxc5 2.Qb6# in the solution of Example 2, or 1...Rxe5 2.Qf2#
in the try of the same problem (Sorry, I missed to underline this variation as thematically related!).

a4) All empty squares may be filled with new mates, as in Examples 3 & 4.

b) In "~" squares it is not allowed to repeat any thematic variation, even when the Black move
doesn't refute the threat (as in #2 by Baumann, explained on page 1).

So:

b1) In the two empty squares in the set-play there may be no X.

b2) In the only empty square in the try there may be no X and there should be no A (see Demand No.3).

b3) In the only empty square in the solution there may be no X and there should be no B (see Demand No.3).

Concretly, in the Example 5, set-variations 1...Kd1 2.Bh5# or 1...Kf3 2.Bh5# would eliminate the entry from this TT.

Other types of repetitions, such as 1...Kb4/Bd5 2.Qa3# in the solution of Example 6, damage thematic purity.

Applying the 3 demands/criteria (mentioned at the beginning of announcement) to the 16 thematic examples should help too,
but all further questions will be more than welcome!

Hi, Marjan.

Is it a TMC, if mate A returns in the solution in response to defence b, not d?

Scheme

Set
1...a 2.X

Try 1...a 2. A
1...b 2. X

Solution
1...a 2.B
1...b 2.A
1...c 2.X

What is it? Super TMC?

Excellent point, Anatoly, thanks!

This combination would be highly thematic for this TT and would be the 1st of its kind,
according to my investigations (thanks to Udo and Christian!)

The question of label is less important, but I would classify it as a more complex
and more compact type of TMC, adding one more change to the basic TMC pattern.

By the way, do you know of any analogously "compacted" type of TTC (that I used as model for TMC),
where the 1st and the 2nd threat reappear after the same defence in different phases?
This type of TTC could also be discriminated as a separate case.

No, Marjan, I don't know such examaples. I never was into TTC much.
As for TMC I hope to show my original examples in the tourney.

Found my problem with DMC

Anatoly Slesarenko
A673 Problemist Ukrаiny 2021
HM

(= 9+13 )

1...Q*e5 2.Qd7#
1...Sc4(a) 2.Sc2(X)#!
1.Rc*c5? - 2.Qd7, Sc2(X)#
1...Sb4 2.Sb3#
but
1...Q*e5!
1.Re3? - 2.Qd7#
1...Sc4(a) 2.Rd3# [Sc2?]
1...e5(b) 2.Sc2(X)#!
1...Sc~(c) 2.Q*c5#
but
1...c4!
1.Re*c5! - 2.Qd7# [Sc2?]
1...Sc4(a) 2.R1*c4#
1...e5(b) 2.Rd5#
1...Sc~(c) 2.Sc2(X)#!
1...Sb4! 2.Sb3#
DMC (X) with extra change of play and changed mates.

Many thanks for this important DMC specimen, Anatoly!

If anybody finds some more missing examples, please, post them here!

marjan,

in the announcement you wrote:
"Unique thematic Black defences are preferable, especially in the try and solution."

can be a random-move defence (like in anatoly´s example) considered "unique thematic defence"?

Thanks for the question, Peter.

If it is about the theory of chess composition, I don't know the exact answer.
What matters for this TT is that a random thematic defence will be considered
the same as unique moves.

Of all multiple defences it is probably the closest one in appearance to unique defence,
and even uses the same number of characters in notation (sometimes less).

When you check all 16 thematic examples from the announcement you will find random thematic defences
in Nos. 2, 7, and 8. None of them were criticised for using random thematic moves, and some were praised
for including Black Correction.

Anyway, what is "preferable" for the judge is only a slight guidance,
it will not be more important than the content and the overall impression.

thank you, majran.

one more comment to the examples 3 and 4 from your list.
they don´t have exactly the same structure. example no. 3 contains also reciprocal change, thus the formula is Z-33-36, while no. 4 has 7 mates altogether, so the formula is Z-33-37.

True, thanks a lot, Peter!

All corrections and additions will be included in future versions of the document.

Since week ago the section for entering problems has been working,

In case you have less experience with it, go to the Originals Section on the left vertical menu.
In it you will find "Jurmala 2024 IT #2" section, and the announcement.
Next, check the "Select a tournament (section)" and choose the right one.
If you choose Forsyth notation for starting position you may simply copy/paste the FEN.

When you enter your problem, don't forget to check the section "My originals: Jurmala 2024 IT #2".
There you can make all needed correction till the deadline 15th July.

Deadline is 10th of June, is it?!

In the announcement it says July 15th. Would be nice to be clarified.

Is there any other way how to submit the original to the tourney besides entering on the MatPlus site? Either by sending by e-mail somewhere or by having the entries entered by someone registered?
I am asking because I know some composers who would be interested in participation, but they are not registered on the site.

Sorry, Anatoly, the right deadline is 15th July, of course,
as written in the announcement amd in the MP section Originals!
My typo, after writing about YCCC-8 deadline (10th June), is now edited and corrected.

(17) Posted by Marjan Kovačević [Sunday, Jun 9, 2024 01:09]

Yes, Juraj, any registered Mat Plus user may enter a problem for his friend.

The last day!
20 entries by now for a demanding theme sounds very good!