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MatPlus.Net Forum General Longest unique series mover
 
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(1) Posted by Hauke Reddmann [Monday, Oct 24, 2022 21:41]

Longest unique series mover


https://chess.stackexchange.com/questions/40837/longest-sequence-of-unique-series-moves
From the fleeting remark in the Obituaries section, here is a little
construction game: Starting position, remove black pieces, now
try the longest ser-SPG. Here are 22 by Evargalo:
1. Nc3 null 2. Ne4 null 3. c3 null 4. Qa4 null 5. Qa8 null 6. a4 null 7. Ra3 null 8. Rb3 null 9. Rb6 null 10. b3 null 11. Ba3 null 12. Be7 null 13. Bh4 null 14. Ng5 null 15. e4 null 16. Ke2 null 17. Kd3 null 18. Kc4 null 19. Kb5 null 20. Ka6 null 21. Ka7 null 22. Ba6
 
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(2) Posted by Kevin Begley [Tuesday, Oct 25, 2022 05:20]

Unless I'm missing something, the series mover in 31.0 by François Labelle (Phénix) is cooked by 25.Nf6 and 26.Nh5 (as opposed to 25.Ndf4 and 26. Nh5).

Nor can you fix this with 24.Bh2 25.Ndf4 26.Ng2 27.f4 etc, because that's cooked too (the Knight can go to g2 earlier).
 
 
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(3) Posted by James Malcom [Tuesday, Oct 25, 2022 06:28]

That is odd, because a comment on PDB said Jacobi verified it: https://pdb.dieschwalbe.de/P1347359. Which version of Jacobi is not specified, but it is clearly the latest given the date. That, and the fact it is Labelle. I used Heuristic mode to fast track obtaining the solution, and it found only that one. Yes, it is not a C+, but still, odd.
 
   
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(4) Posted by Georgy Evseev [Tuesday, Oct 25, 2022 08:04]

Nf6 is illegal as it is a check to black king
 
   
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(5) Posted by James Malcom [Tuesday, Oct 25, 2022 09:00]

I now realize it is unclear if Labelle's position is meant to have the Black pieces as well.
 
   
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(6) Posted by Joost de Heer [Tuesday, Oct 25, 2022 09:36]

I think Francois' problem is supposed to be a Kriegspiel composition.
 
   
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(7) Posted by Kevin Begley [Tuesday, Oct 25, 2022 09:39]

That would explain it -- it's a series mover in Kriegspiel.
Thanks Joost, Georgy, and James.

But, if that's the case, it doesn't explain other compositions on that same page.
For example:

1. Nc3 null 2. Ne4 null 3. c3 null 4. Qa4 null 5. Qa8

How can white play Qa8?

Also:

1. Nf3 null 2. Nd4 null 3. f3 null 4. Kf2 null 5. Ke3 null 6. Ke4 null 7. Kd5 null 8. Kc6 null 9. Kb7 null 10. Ka8

8.Kc6 should be illegal, as should 9.Kb7 -- how do you explain that?


I will assume you are correct, and not everyone on that page is in agreement about the task.
 
   
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(8) Posted by James Malcom [Tuesday, Oct 25, 2022 09:48]

I pulled my "solution" from Jacobi heuristics under the assumption it was a seriesmover. Kriegspiel, or not, it is clearly not so.
 
   
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(9) Posted by Kevin Begley [Tuesday, Oct 25, 2022 09:56]

@James,

You can not trust Heuristic Mode in Jacobi -- says so in the documentation (this mode will eliminate duals).
It is good for finding solutions faster (but it's not reliable for assuring soundness).
 
   
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(10) Posted by shankar ram [Tuesday, Oct 25, 2022 12:03]

I think there are two separate categories here:
1) With Black pieces in the initial game position. Here, moves like a WS going to f6 would be illegal (unless it was the last move!). No need to bring in Kriegspiel.
2) Without Black pieces. Here, White could happily move anywhere on the 7th and 8th ranks. So, a sequence like c3, Qa4, Qa8 is possible.

The PDB examples belong to the 1st type, as can be seen in the forsyth code which includes Black pieces.
 
   
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(11) Posted by Joost de Heer [Tuesday, Oct 25, 2022 21:21]

This is the diagram in Winchloe for Francois Labelle's composition:
(= 16+16 )

ser-dia31
 
   
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(12) Posted by James Malcom [Wednesday, Oct 26, 2022 04:04]

shankar is correct. These are Type 1s. My answer is partially salvageable, d my chipping off White moves until it is unique.

Labelle's can be gutted to 24, C+ by Jacboi:

EnglishN
forsyth 8/8/8/8/8/8/PPPPPPPP/RNBQKBNR
stipulation ser-a=>b24 forsyth 8/8/Q6R/P2N2R1/6P1/2PPP2P/1P2NP1B/1B2K3

Perhaps it can be extended to 29 with a different move order, starting at 24.

1. Nc3 null 2. Nd5 null 3. c3 null 4. Qa4 null 5. Qa6 null 6. a4 null 7. a5 null 8. Ra4 null 9. Rg4 null 10. Rg5 null 11. g4 null 12. Bg2 null 13. Be4 null 14. Bb1 null 15. d3 null 16. Bf4 null 17. e3 null 18. Ne2 null 19. Rg1 null 20. Rg3 null 21. Rh3 null 22. Rh6 null 23. h3 null 24. Bh2 null 25 f4 null 26. Kf2 null 27. Kg3 null 28. Kh4 null 29. Ng3
 
   
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(13) Posted by Andrew Buchanan [Wednesday, Oct 26, 2022 07:48]

I agree with Shankar. There’s another dimension whether promotions are permitted. There’s a couple of way longer records in PDB involving White promotions (warning for the sensitive: non-standard material appears in these diagrams).
 
 
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(14) Posted by Joost de Heer [Wednesday, Oct 26, 2022 07:52]

Attempt for 30:
(= 16+0 )

23. Rc6 24. Bd6 25. f4 26. Kf2 27. Kg3 28. Kh4 29. Kh5 30. h4
 
   
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(15) Posted by Joose Norri [Thursday, Oct 27, 2022 13:28]

A related record is P1361958 "New attempt (not fully computer-tested...) for record of shortest Series Proof Game leaving black King alone." Now C+ according to Jacobi. So here you aim for a shorter one.

Suomen Tehtäväniekat 01/2015
Dedicated to Unto Heinonen
7. ehrende Erwähnung

(= 16+1 )


1. a4 2. Ta3 3. Th3 4. c3 5. Dc2 6. Dxh7 7. Dxg8 8. Txh8 9. h4 10. Th3 11. Td3 12. Txd7 13. d3 14. Lf4 15. Lxc7 16. Lxd8 17. Txb7 18. Txb8 19. Txc8 20. Txa8 21. Txa7 22. Lxe7 23. Lxf8 24. Txf7 25. Lxg7#
 
   
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(16) Posted by Joost de Heer [Thursday, Oct 27, 2022 14:26]

@Joose: As Francois wrote in his comment, there's no 24-mover with only a black king remaining (assuming no programming errors).
 
   
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(17) Posted by Joose Norri [Friday, Oct 28, 2022 14:48]

@Joost: now the question regarding that task is if there is another 25 mover...
 
   
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(18) Posted by James Malcom [Saturday, Oct 29, 2022 20:20]

Evargalo found a far different set up for 30 that I C+ed with Jacobi (EnglishN forsyth 8/8/8/8/8/8/PPPPPPPP/RNBQKBNR stipulation ser-a=>b30.0 forsyth K7/1B6/5B2/8/6PQ/1PN2N2/1RPPPP1P/1B3R2).

Evargalo, www.chessstackexchange.com, 10/28/2022
(= 16+0 )


https://chess.stackexchange.com/a/40842/15543
 
 
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(19) Posted by Olivier [Friday, Nov 4, 2022 16:03]

Re- Joost de Heer [Wednesday, Oct 26, 2022 07:52]

There is extra Ph2 on your diagram, but anyway I think this attempt is cooked because you can switch the role of each rook:
Ra4-c4-c6 and Rh1-g1-g3-h3-h5-g5, leading to many duals.

Maybe Ra8/Bb8 (or Qa7/Ra6/Bd6) instead of Rc6/Bd6 can save your idea.

Edit: no it doesn't. 1.h4 4.Rh3-g3-g5, bringing the Ra1 to a6 or a8, d3, Bf4-b8, e3, Ke2-h5, Be2-d1-c2-b1, etc... would give alternative 30-moves solutions.
You need to leave the h-pawn on h2 to prevent the fast escape of the Rh1, but then you reach only 29 moves...
 
   
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(20) Posted by Olivier [Friday, Nov 4, 2022 20:02]

This is not C+ (yet ?), but it attempts to reach 34 moves:

(= 16+0 )


This less ambitious version in 32 moves is C+ :

(= 16+0 )

 
   
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MatPlus.Net Forum General Longest unique series mover