Author: Heiner Marxen
Date: 14:00:52 06/02/99
Go up one level in this thread
On June 02, 1999 at 08:13:00, Bernhard Bauer wrote: >On June 02, 1999 at 07:52:15, blass uri wrote: >> >>On June 02, 1999 at 06:58:04, Bernhard Bauer wrote: >> >>>On June 02, 1999 at 05:00:17, Dan Newman wrote: >>> >>>>Well, I tried mine out on these at 1 min / position on a P6/200 >>>>and got the key move in 10 out of 16, but no mates. I then tried >>>>them at 1/2 hr each and still got 10/16 and no mates. Finally, I >>>>tried the first one for two hours -- still no mate... >>>> >>>>On the next to last (BWTC.0647) my program likes to force a >>>>repetition draw all the way through the 18 ply search -- no >>>>guarantee there isn't a mate though >>> >>>This position is so simple and nice that you should have a look at it >>>and solve it yourselv. Not only your program fails, Crafty16.8 fails too. >>>I guess your program depends heavily on null move? >>>Oh, I'm missing the point again, sometimes I feel like a null-move-basher. >>>But as we all know such positions do *never* apear in practice, so why care? >> >>I do not believe that such positions never appear in practice. > >Ah hmm ... do I? > >>Junior has no problem to find the move but cannot find the mate because it >>does not use nalimov tablebases. >> >>I think that it is simple to find mate in X here. >>You only need to use the KQvs KPP tablebases and not to use the null move. > >Looks like a mate in 16. No, it is a mate in 12 (according to my problem solver): W: Kh2 Qh7 (2) B: Kh4 Qg4 Pg6 Ph5 (4) FEN: 8/7Q/6p1/7p/6qk/8/7K/8 w - - Time (user) = 122.05 sec (ca. 2.0 min) E.g.: 1.Qe7+ Qg5 2.Qe4+ Qg4 3.Qe3 Qg2+ 4.Kg2: Kg4 5.Qf3+ Kg5 6.Kh2 Kh6 7.Kg3 Kg7 8.Kh4 Kg8 9.Kg5 Kg7 10.Qb7+ Kf8 11.Kf6 Ke8 12.Qe7+ The critical move is 3.Qe3 (no check) putting black into zugzwang. Therefore this is a null move issue, again.
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