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MatPlus.Net Forum General Troublesome Position
 
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(1) Posted by Bob Baker [Thursday, Jun 1, 2023 03:49]

Troublesome Position


Below I have listed a position and a 26.0 move proof game for it. When I give the position to Euclide 1.11, it halts immediately after reporting "Analysis completed. Some promoted pieces can't be explained". When I give the position to Stelvio 1.2, it halts immediately after reporting "Done. No solutions found".

I am wondering if those who use other solving programs could see what they do with the position.

rnb3nk/2ppppb1/1r2rr2/7p/P7/K1RR2R1/1BPqPP2/1N2QBNR

1. h4 a5 2. h5 a4 3. h6 a3 4. hxg7 axb2 5. a4 h5 6. Ra3 Rh6 7. Rc3 Rf6 8. Na3
Nh6 9. g8=R b1=R 10. Rgg3 Rbb6 11. Rgd3 Rbe6 12. g4 b5 13. g5 b4 14. g6 b3 15.
g7 b2 16. g8=R b1=R 17. Rgg3 Rbb6 18. Bb2 Bg7 19. Qa1 Kf8 20. Kd1 Kg8 21. Kc1
Kh8 22. Kb1 Qg8 23. Ka2 Qh7 24. Qe1 Ng8 25. Nb1 Qh6 26. Ka3 Qxd2
 
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(2) Posted by Kevin Begley [Thursday, Jun 1, 2023 04:58]

I'm on it.

This will take a while, but it looks like I can completely verify (or cook) this with Jacobi (I'm at 0.04% after 600 seconds).

I'm also running in Demolition mode (at pass 16 after 600 seconds), and I'm running in Demolition+Heuristic Mode (at pass 33 after 600 seconds).

I'll let you know when a solution is found.
 
 
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(3) Posted by Kevin Begley [Thursday, Jun 1, 2023 06:02]

I found a solution, at or before pass 46 (4600 seconds)

1.h4 a5 2.h5 a4 3.h6 a3 4.hxg7 axb2 5.a4 h5 6.Ra3 Rh6 7.Rc3 Rf6 8.Sa3 Sh6 9.g8=R b1=R 10.Rgg3 Rbb6 11.Rgd3 Rbe6 12.g4 b5 13.g5 b4 14.g6 b3 15.g7 b2 16.g8=R b1=R 17.Rgg3 Rbb6 18.Bb2 Bg7 19.Qa1 Kf8 20.Kd1 Kg8 21.Kc1 Kh8 22.Kb1 Qg8 23.Ka2 Qh7 24.Qe1 Sg8 25.Sb1 Qh6 26.Ka3 Qxd2


Note: this does not mean this solution is unique -- it may take a few days to confirm there is no alternative solution.
 
   
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(4) Posted by Bob Baker [Thursday, Jun 1, 2023 06:58]

Thank you. I will be interested in what you learn about uniqueness. I have made reports to the maintainers of Euclid and Stelvio.
 
   
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(5) Posted by Georgy Evseev [Thursday, Jun 1, 2023 07:23]

Natch under WinChloe found this very fast

1.Nc3 Nf6 2.h4 a5 3.h5 a4 4.h6 a3 5.hxg7 axb2 6.a4 b1=R 7.Ra3 Rb6 8.g8=R Re6 9.Rg3 b5 10.Rd3 b4 11.g4 b3 12.g5 b2 13.g6 b1=R 14.g7 Rb6 15.Bb2 h5 16.g8=R Rh6 17.Rg3 Bg7 18.Qa1 Kf8 19.Kd1 Kg8 20.Kc1 Kh8 21.Kb1 Qg8 22.Ka2 Qh7 23.Qe1 Ng8 24.Nb1 Rf6 25.Rc3 Qh6 26.Ka3 Qxd2
 
   
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(6) Posted by shankar ram [Thursday, Jun 1, 2023 07:34]

Reto replied: "...Stelvio solves this in less than 4 minutes. (it is cooked)".
https://cdn.discordapp.com/attachments/758335042752741386/1113701279357747271/grafik.png
 
 
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(7) Posted by Kevin Begley [Thursday, Jun 1, 2023 07:37]

Yep. I can confirm that the problem is cooked.

I'd say good luck fixing this, but I'm frankly not sure exactly what you are trying to achieve (whatever it is, promoted force is not a pretty way to get there).
I'd suggest you go back to the drawing board.
 
   
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(8) Posted by seetharaman kalyan [Thursday, Jun 1, 2023 07:55]

Well... There are four solutions listed
 
   
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(9) Posted by Joost de Heer [Thursday, Jun 1, 2023 08:04]

Well, Stelvio can be configured to stop after X (in this case 4) solutions are found.
 
 
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(10) Posted by Bob Baker [Thursday, Jun 1, 2023 08:19]

Here is an update on my troublesome position. After getting replies from Reto Aschwanden and Étienne Dupuis that they had solved the position with no problems, I started over and did my testing again. My results were the same as theirs. I must have had a mistake in my input file, although I had checked it several times. The solution is not unique, and both programs cooked the position in about one minute.

I want to thank Kevin Begley for his effort to help me check on what I had thought was a strange bug in two programs.
 
   
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(11) Posted by Kevin Begley [Thursday, Jun 1, 2023 15:17]

Seems many people helped you, some more than I did.
You are welcome.
 
   
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(12) Posted by Bob Baker [Saturday, Jun 3, 2023 10:27]

Keving Begley wondered exactly what I was trying to achieve, so I wanted to explain that. The position I was testing was posted by a regular poster in the the Shortest-Proof-Game Challenge topic in the Fun With Chess forum at chess.com. It was being proposed as a possible new record for the longest unique SPG composed by a regular contributor to that topic.

Except for James Malcom, the participants in that topic are not recognized problemists and are known to me only by their chess.com screen names. They are not trying to create competition-level compositions, but are just seeking to have fun by solving proof games, not necessarily unique, that they have found in various sources or composed themselves. The latest record position for longest unique SPG is given below, composed by EvinSung, with a length of 29.5 moves and verified as unique by Stelvio 1.2 after analyzing it for 49 minutes and 13 seconds.

rnb5/1Qppppbk/4rr1R/P6p/4B3/N1RR4/2PPPP1n/1nBq1NQK
 
   
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(13) Posted by Kevin Begley [Saturday, Jun 3, 2023 11:46]

I see. Thanks for the clarification, Bob.
I fully support that challenge (anything that encourages more interest in proofgames).
 
 
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MatPlus.Net Forum General Troublesome Position