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1 problem(s) found in 3113 milliseconds (displaying 1 problem(s)). [PROBID='P1263434'] [download as LaTeX]

1 - P1263434
Milan Velimirovic
720 Rokada 1978
3. Preis
P1263434
(2+11)
#27
1. Ke1 e5 2. Ke2 e6 3. Ke1 e4 4. Ke2 e3 5. Ke1 e2 6. Kxe2 e5 7. Ke1 e4 8. Ke2 e3 9. Ke1 c6 10. Ke2 c5 11. Ke1 c4 12. Ke2 c3 13. Ke1 b6 14. Ke2 b5 15. Ke1 b4 16. Ke2 b3 17. Ke1 a6 18. Ke2 a5 19. Ke1 a4 20. Ke2 a3 21. Ke1 e2 22. Kxe2 a2 23. Ke1 h5 24. g6 h4 25. g7 h3 26. g8=D h2 27. Dg5#
play all play one stop play next play all
Alexej Oganesjan: Duals in non-author's full length variations:
- 21...a2 22.Ke2 h5 23.g6 h4 24.g7 h3 25.g8Q h2 26.Qg2/Qg3/Qd5/Qg5/Qe6/Qh7/Qa8/Qe8/Qh8 ~ 27.Qh1#/Qxe3# or 25.g8R h2 26.Rh8 h1Q 27.Rxh1#;
- 21...h5 22.g6 h4 23.g7 h3 24.g8Q h2 25.Qg2/d5/h7/a8/h8 h1Q 26.Qxh1 e2 27.Kxe2#/Qh6#. (2016-12-04)
Olaf Jenkner: Yes, but one dual-free variation should be enough to say C+. (2016-12-04)
Frank Müller: For me is one dual-free variation NOT enough to say C+ (2016-12-04)
VL: I fully agree with Olaf: C+! In general, "alternative black moves are not normally considered duals" (Codex for Chess Composition, version Ostroda 2015; Footnote 14A to Article 10 – Dual). (2016-12-05)
A.Buchanan: (1) This isn't just alternative black moves though. In the lines that Alexej quotes, there are alternative white moves. So formally yes there are duals, but I don't think it detracts from the problem in the slightest.
(2) These lines are core because it's here that we find the reason why 1. Ke2? doesn't work (which ought to be given as a non-solution here.)
(3) Codex does not mention phrase "C+" as notation. A problem might be considered to be sound but not C+. (2017-09-19)
VL: (1) We discuss exclusively the formal soundness, what suffices for long moremovers. The indicated line is dual free, ergo the problem is sound. Regardless of other
variations (including "non-author's" ones that represent weaker defenses of Black, etc.). The same for the natural attempt 1.Ke2?. It is desirable to have a dual-free
refutation of it (a proper thematic try). But this is not about the soundness of the problem as such. (Of course such a conclusion would be absolutely false, say, with respect to 2-movers, for which the notion of soundness is less formal, much more delicate and arguable sometimes.)
(2) Milan's problem was verified partially on popeye and fully on WinChloe, afaik. Analyses of the outputs confirmed: there are no cooks and there are dual-free full-length lines (a huge number of them, together with numerous shorter or dualized lines, etc.; it doesn't matter). So, the verdict "C+" is quite justified, imho. Of course, not merely because the problem is sound. (2017-09-19)
A.Buchanan: Thank you: I didn't know that was the definition of soundness for long moremovers. Certainly the Codex does not hint at it: maybe it's too detailed a point for that document. (2017-09-20)
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comment
Keywords: Minimal
Genre: n#
FEN: 8/ppp1p2p/4p3/6P1/8/8/1pp5/brk2K2
Reprints: Problemas 18, p. 479, 04/2017
Input: Frank Müller, 2013-02-26
Last update: A.Buchanan, 2017-09-18 more...
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