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MatPlus.Net Forum Selfmates Logical problem with false plan
 
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(1) Posted by Aleksey Oganesjan [Monday, Oct 4, 2021 14:01]

Logical problem with false plan


New (??) opportunity to expand a content of logical problems:

1) there is a try 1.Х? - false main plan that is not succeed due to some obstackle;
2) there is another try that begins with false foreplan 1.Y?, after which the false main plan X is threatening. But the plan X is not succeed again, herewith of course for some other reason (for example, during execution of false foreplan, White allow a new weakness that Black uses);
3) of course there is no successful realization of the false main plan (that's why it is false!);
4) further - everything is as in an usual logical problem: an actual main plan, its unsuccessful attempt at the beginning and successful after an actual foreplan.

It seems that a major difficulty is to achieve that the false plan is somehow clearly connected with the actual solution. Otherwise, a couple of false tries of the false plan can be seemed artificially "screwed" onto the rest of the solution.

Aleksey Oganesjan
Belyakin-100 MT, 2021
I-II Prize
(= 10+12 )

s#9

False main plan: 1.Qb8+? Rxb8 2.axb8B – 3.Be5 – 4.Rxg8+ Bxg8#, but 2...Sxb5! 3.Be5 Sd4+! 4.Bxd4 cxd4!
False foreplan: 1.Rxa3? (2.Qxb8+ and etc.), but 1...b1B! 2.Qb8+ Rxb8 3.axb8B Bf5+! 4.Ke5 – Black responded symmetrically to the threat of promotion in Bishop, and White did not have time to block e5.

Actual main plan 1.Qe5? is not succeed at once because in a few moves White Queen will need access to c5, which is now guarded by Black Bishop. Therefore, White needs to interfere this Bishop first.
Actual foreplan:

1.e4!

It's threatening 2.e5 ~ 3.Rxg8+ Bxg8#, and any attempt to check to wK leads to checkmate: 1...Sxb5 2.e5 Sxc7(d4)# or 1...b1Q(B) 2.e5 Q(B)f5#.
That's why Black is forced to en-passant capture:

1...fxe3 e.p.

And now – a familiar plot: forcing of castling and further uncastling for elimination of obstackle of main plan.

2.Qe5! 0-0-0 3.Bb7+ Kxb7 4.a8Q+! Rxa8 5.Rxb6+ Kc8 6.Qxc5+ (that's why White needed to interfere Bf2!) 6...Kd8 7.Qc7+ Ke8 8.Qe5! ~ 9.Rxg8+ Bxg8#.

Concept of problem: in false plan White eliminates Black castling by "ordinary" way but fails; in actual plan White uses non-standard way for eliminating of castling (well-known by https://yacpdb.org/#424634) – by forcing of it and further uncastling.

As compared with the pointed out partial self-anticipation, there were added: false plans, actual foreplan 1.e4 fxe3 e.p. and thus Valladao, a removal of dual a8Q(B)+.
 
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(2) Posted by Mark Kirtley [Wednesday, Oct 13, 2021 23:26]

Aleksey, thanks for showing this cool problem. I also tried 1.Bxh8 for another "ordinary" way of eliminating Black's castling option, while supporting the actual main plan, and I see why it doesn't work.
I myself have tried to compose a logical selfmate with foreplan, but I've yet to be successful!

It seems to me that your recent selfmate in The Problemist might trick many a solver into thinking it is logical problem with foreplan. I'll quote the problem here, now that the solution has been published, and then say what I mean.

Aleksey Oganesjan
S2849, The Problemist, March 2021
(= 11+8 )

S#8

solution: 1.Rc2+ Sc4 (1...Sxc2? 2.b4+ Scxb4#) 2.Qf2+ Sde3 3.Rf5+ Bd5 4.Sxd5+ Qxf8 5.Sxe3+ Qxf5 6.Sxc4+ Qxf2 7.Sxb6+ Qxc2 8.Sa4+ Qxa4#.

(What a problem!) Now what I mean is, 1.b4+ Sxb4# would work as an actual main plan, if some way could be devised to get the wQ off the 5th rank, and that way would be the actual foreplan. But there is no such way! So I wonder if it is fair to say that viewing the problem as logical is a sort of try!
 
 
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(3) Posted by Aleksey Oganesjan [Thursday, Oct 14, 2021 08:45]

Dear Mark, thank you!

Hm, yes, in my s#8 the move 1.b4+? Sxb4#?? can be consider as a "false main plan". By the way, it's can be compared with my s#10 (https://pdb.dieschwalbe.de/P1359754) where a main plan (real, actual!) 1.e4+ fxe3ep# is also initially unlucky in view of pin, but in that s#10 the White finds a way to unpinning, unlike s#8!
 
   
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(4) Posted by Joost de Heer [Thursday, Oct 14, 2021 12:57]

 QUOTE 

By the way, it's can be compared with my s#10 (https://pdb.dieschwalbe.de/P1359754) where a main plan (real, actual!) 1.e4+ fxe3ep# is also initially unlucky in view of pin

Main plan fails because the mating piece can be captured, not because it's pinned.
 
   
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(5) Posted by James Malcom (Rewan Demontay) [Tuesday, Dec 14, 2021 19:32]

I have entered this problem into YACPDB: https://www.yacpdb.org/#554786

It now joins with its brethren of uncastling problems.
 
   
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(6) Posted by James Malcom (Rewan Demontay) [Friday, Dec 17, 2021 02:49]

I noticed a tidbit of irony when entering the SuperProblem TT "Logical castling" into YACPDB, of which Aleksey Oganesjan was the judge. The award is readily available: http://superproblem.ru/doc/tourneys/other/2017/tt_logical_uncastling_award_eng.pdf

(The announcement for the curious: http://superproblem.ru/doc/ads/2016/tt_logical_uncastling_rus.pdf)

At the end, he said: "The tourney theme requires at least 6 moves and can be shown only in genres with a struggle of sides. Therefore, at the present moment, after little more than a year of its existence, the theme is already embodied in all three possible genres – direct mates, selfmates and studies. In the future, it would be interesting to see a synthesis of this theme with another themes/ideas, for instance with downright obvious Vallodao task."

And what do we have here? An uncastling Valladao produced by the judge himself!
 
   
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(7) Posted by Aleksey Oganesjan [Friday, Dec 17, 2021 07:36]

> I have entered this problem into YACPDB

Thank you very much, James! I had been planning to do it myself for a long time, but there was no free time.


> And what do we have here? An uncastling Valladao produced by the judge himself!

Oh, yes, I recently thought of the same: if you do not fulfill your goal yourself, no one will do it for you! :-))
 
   
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(8) Posted by Joaquim Crusats [Saturday, Dec 18, 2021 08:27]

In 2015 I published a problem with a logical "uncastling" in retro form:

Joaquim Crusats
Problemas, 2015
(= 12+13 )

Proca -7 & #1

Main plan: -1.Sd7-b6 threatening -2.Sb6-a8 & 1.c8=S#; but there is an obstacle: -1…b6-b5! White needs a foreplan to illegalize Black’s defense:

Solution: -1.Kd2-e1 Rb2-a2 -2.Rd1-a1 R~-b2 -3.Kc1-d2 R~(+); note that White’s two first retractions do not transpose because the bR cannot be allowed to reach the c1 square; -4.0-0-0 R~ -5.d2-d4; note also that this move must be retracted after the uncastling because otherwise the bRc4 could prevent the uncastling (both bRs are used to assure that there are no transpositions of moves in the solution); -5…~ and now the main plan works: -6.Sd7-b6 ~ (-6…b6-b5? is now illegal because then the dark-squared bishops could not have crossed via a1 owing to the uncastling; with an empty b6 square, though, the bBb4 can retract to b8, then, the bPb5 retracts to b6 to uncapture the ds-wB implying that the bBb8 was promoted on g1, and then the original ds-bB can be uncaptured on c3 when the original ds-wB is back to his homebase; finally, the original ds-bB can go to f8 and the cage is released with e7xXd6; -7.Sb6-a8 & 1.c8=S#.
 
 
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MatPlus.Net Forum Selfmates Logical problem with false plan