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MatPlus.Net Forum General A Challenge-7 Black Queens In A Selfmate
 
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(1) Posted by Rewan Demontay (Real Name: James Malcom) [Monday, Jun 15, 2020 19:37]; edited by Rewan Demontay (Real Name: James Malcom) [20-06-15]

A Challenge-7 Black Queens In A Selfmate


Awhile ago, I managed 6 Black queens in a selfmate-http://superproblem.ru/archive/probl/Sn/Malcom-s15-2020.gif

But 7 black queen promotions has eluded me ever since. Below is the best and only scheme I have personally found so far that has potentional.

s#17
(= 6+14 )


The ideal solution-1. Nc7 or similar b1=Q 2. Ra8 Qa1+ 3. Rxa1 c1=Q 4. Ra8 Qa1+ 5. Rxa1 d1=Q 6. Ra8 Qa1+ 7. Rxa1 e1=Q 8. Ra8 Qa1+ 9. Rxa1 f1=Q 10. Ra8 Qa1+ 11. Rxa1 g1=Q 12. Ra8 Qa1+ 13. Rxa1 h1=Q 14. Ra8 Qa1+ 15. Rxa1 Bd7 16. Ra8+ Bc8 17. Rxc8+ Ne8# (16... Be8 leads to duals, but I think it is acceptable on the last move of such a monumental task.)


Who here can achieve it? I offer co-creation on my scheme, but I highly encourage you to try and make your own. If you do not wish to post here, my email-rewandemontay@gmail.com. In the event that you manage to create it and publish it elsewhere, please share it here when you can.
 
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(2) Posted by Rewan Demontay (Real Name: James Malcom) [Sunday, Aug 23, 2020 17:05]

Sucess at last!

After half a year, it is done at last. In the end, irony completed my quest. I spent so much time looking for a working matrix for 7 Black queen promotions, and yet the final product ended merely being an extension of what I found for 6

James Malcom, Superproblem 22/8/2020
s#17
(= 9+15 )


Although not computer tested, the number of possible checks is extremely limited and each has an easy refutation that leaves Qa1+ as the only possible option. The cage around White's selfmating threat is thick enough that no queen move can tear it down in one move.

This most certainly took a long time to accomplish!
 
 
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(3) Posted by Olaf Jenkner [Sunday, Aug 23, 2020 17:38]

The problem is C+ .
 
   
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(4) Posted by Hauke Reddmann [Sunday, Aug 23, 2020 23:15]

Impressive. Qxf5+ or Qh6+ only shorten it, right?
 
   
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(5) Posted by Olaf Jenkner [Monday, Aug 24, 2020 00:08]

??
Qh6+ Rg6## Doublecheck
Qxf5 exf5 Rxd8+ Sxd8#
 
   
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(6) Posted by Rewan Demontay (Real Name: James Malcom) [Monday, Aug 24, 2020 00:30]

Thanks for the confirmation Olaf. You used Gustav 41d, correct? (Eyeballs roll off and onto to floor to do donuts.) P1379233 needs updated with the info. Sucess succulently tastes so sweet, especially after defeat-https://pdb.dieschwalbe.de/P1372862
 
   
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(7) Posted by Rewan Demontay (Real Name: James Malcom) [Monday, Aug 24, 2020 19:13]

Also also, just for hijinks, here’s 8 in an illegal setting. :)

s#19
(= 11+17 )

 
   
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(8) Posted by Olaf Jenkner [Tuesday, Aug 25, 2020 00:14]

1.Bc6-c7 c2-c1D 2.c7xd8D Ke8xd8 3.Ta7-d7 Kd8-e8 4.Ta6-a8 Dc1-c8 5.Ta8xc8 Sf7-d8#
 
 
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(9) Posted by Rosie Fay [Tuesday, Aug 25, 2020 15:24]

Well done! That looks like a magnificent achievement.

There are many selfmates with multiple promotions in the solution, but, as far as I know, nearly all of these have multiple White promotions, but few with multiple Black promotions. I note the 6 black rooks in P1225124, 6 black knights in P1334568 and 5 black bishops in P1333241. Is it harder to motivate Black to promote in defence, than to motivate White to promote?

What other selfmates are known, where Black successively promotes 2 or more pawns? PDB's search language and keywords do not make it easy to seek such problems. There is no way to require that multiple search strings be found in successive moves of a single solution line rather than in different lines. And K='Allumwandlung, black' is applied to problems with AUW in parallel as well as AUW in series.
 
 
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(10) Posted by Rewan Demontay (Real Name: James Malcom) [Tuesday, Aug 25, 2020 17:57]

To Olaf-Eh, silly me. That’s why you should sleep before composing! I’ll “cook” up another later.

To Rosie-I did some minor pattern searches in YACPDB and I found a few. I’ll leave the solutions out.

Aleksandr Azhusin, Stratafems 2005, 6th Prize
s#5-https://www.yacpdb.org/#504490

(= 12+10 )


Vladimir Zheltonozhko, Magyar Sakkélet 1988
s#6-https://www.yacpdb.org/#67977

(= 7+11 )


Janos Csak,cJubilé Bo Lindgren-50 1992, 1st Prize
s#5 Duplex-https://www.yacpdb.org/#65562

(= 9+10 )

 
 
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MatPlus.Net Forum General A Challenge-7 Black Queens In A Selfmate