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Up Topic Rybka Support & Discussion / Rybka Discussion / Nightmare positions
- - By oudheusa (*****) Date 2008-08-12 17:16
For years I have had a database called Nightmare compiled by Walter Eigenmann that contains 31 positions that so far haven't been solved by chess computers. Everytime a new program version comes out I cannot resist testing it against the first Nightmare position:

1qrrbbk1/1p1nnppp/p3p3/4P3/2P5/1PN1N3/PB2Q1PP/1B2RR1K w - - 0 21


I haven't given it a lot of time but my 1-cpu Rybka 3 version did not get very far. Also with IDeA (Aquarium), Rybka could not find it within a reasonable time limit. However, after entering the first move (Bh7x) it came to a positive score fairly quickly. It still hasn't found the final solution though.

Interested to know what the results are with faster hardware or a program like Zappa.

Solution:

[Event "Georgiev-Ionescu, Constantin 1986"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Nightmare Nr.001"]
[Black "?"]
[Result "*"]
[Annotator "W.Eigenmann"]
[SetUp "1"]
[PlyCount "11"]
[Source "Walter Eigenman"]
[SourceDate "2005.09.30"]

21. Bxh7+ $18 (21. Ng4 $2 Ng6 $11) (21. Ne4 $2 Ng6 $11) 21... Kxh7 (21... Kh8
22. Qh5 $18) 22. Ne4 Kg8 (22... g6 23. Qg4 Bg7 (23... Kg8 24. Qh4 $18) 24. Qh4+
Kg8 25. Qxe7 $18) 23. Ng5 g6 (23... Nf5 24. Nxf5 $18) (23... f6 24. exf6 $18)
24. Ng4 Nf5 (24... Bg7 25. Nf6+ Bxf6 (25... Nxf6 26. exf6 $18) 26. exf6 Nf5 27.
Qf3 $18) (24... b5 25. Qf3 Nf5 26. Qh3 $18) (24... Rc5 25. Qf3 $18) 25. Rxf5
exf5 (25... gxf5 26. Nf6+ $18) 26. Qf2 $18 *
Parent - - By Linus (***) Date 2008-08-12 17:22

> ... Rybka could not find it within a reasonable time limit.


I suppose it all depends how you define "reasonable time limit". For a serious correspondence chess player an analysis can very well last 24 hours or 48 hours and he might still call it a reasonable time limit.
Parent - By oudheusa (*****) Date 2008-08-12 17:24
Well let me know how far you get. I have had engines running for 24 hrs in the past but it was/is quite clear that they just don't get the position.
Up Topic Rybka Support & Discussion / Rybka Discussion / Nightmare positions

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