Author: blass uri
Date: 08:45:54 04/09/98
Go up one level in this thread
On April 08, 1998 at 14:24:34, Christophe Theron wrote: >On April 08, 1998 at 02:45:39, Bernhard Bauer wrote: > >>On April 08, 1998 at 01:56:58, Christophe Theron wrote: >> >>>I think it's a zugzwang problem. I don't know exactly why, but it looks >>>like the black queen has to stay on the a1-h8 diagonal (or else the >>>white queen goes on this diagonal, check, and mate in 2), and has also >>>to stay on the the a file. >>> >>>Or something like that. Anyway, I think black is quickly caught in >>>zugzwang. >>> >>>Programs relying on null move like Fritz (and maybe Crafty?) have >>>problems with this, because a general rule in those programs is that >>>they don't care of zugzwang problem if the queens are on the board. This >>>is correct 99.99% of the time, but not in this position... >>> >> >>Here is some output from crafty: >> >>White(1): hash table memory = 6M bytes. >>White(1): pawn hash table memory = 1.3M bytes. >> >> +---+---+---+---+---+---+---+---+ >> 8 | | | | | | | | *K| >> +---+---+---+---+---+---+---+---+ >> 7 | | | | | K | | | *P| >> +---+---+---+---+---+---+---+---+ >> 6 | | | | | | | | P | >> +---+---+---+---+---+---+---+---+ >> 5 | | | | *P| | | Q | | >> +---+---+---+---+---+---+---+---+ >> 4 | | | | | | | | | >> +---+---+---+---+---+---+---+---+ >> 3 | | | | | | | | | >> +---+---+---+---+---+---+---+---+ >> 2 | | | | | | | | | >> +---+---+---+---+---+---+---+---+ >> 1 | *Q| | | | | | | | >> +---+---+---+---+---+---+---+---+ >> a b c d e f g h >> >>White(1): end-game phase >> clearing hash tables >> time surplus 0.00 time limit 5:00 (5:00) >> depth time score variation (1) >> 6-> 0.84 0.29 1. Qf4 Qa7+ 2. Ke6 Qb6+ 3. Kxd5 Qb3+ >> 4. Kc5 Qe6 5. Qf8+ >> 7-> 1.79 0.00 1. Qf4 Qa7+ 2. Ke6 Qb6+ 3. Kxd5 Qb5+ >> 4. Ke6 Qe8+ 5. Kf6 Qf8+ 6. Kg5 Qxf4+ >> 7. Kxf4 >> 8-> 3.70 0.12 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qe1+ 4. >> Kxd5 Qd2+ 5. Ke5 Qd3 >> 9-> 5.00 0.22 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4. >> Ke5 Kg8 5. Kxd5 Qb6 >> 10-> 9.78 0.00 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4. >> Kxd5 Qb5+ 5. Ke6 Qe8+ 6. Kf6 Qf8+ 7. >> Kg5 Qxf4+ 8. Kxf4 >> 11-> 16.43 0.00 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4. >> Kxd5 Qb5+ 5. Ke6 Qe8+ 6. Kd5 Qf7+ 7. >> Qxf7 >> 12 22.23 ++ 1. Qe3!! >> 12 29.48 Mat09 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qg7 4. >> hxg7+ Kxg7 5. Kxd5 >> 12-> 47.53 Mat09 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qg7 4. >> hxg7+ Kxg7 5. Kxd5 >> time: 47.54 cpu:0% mat:-1 n:4443263 nps:93444 >> ext-> checks:825089 recaps:8581 pawns:15123 1rep:134501 >> predicted:0 nodes:4443263 evals:370831 >> endgame tablebase-> probes done: 37303 successful: 37303 >> hashing-> trans/ref:63% pawn:99% used:w93% b99% >> >>Crafty will mate in 9 moves. >> >>So crafty seems to be pretty good on this problem. >>Kind regards >>B. Bauer > >Crafty finds the solution with the endgame table bases (EGTB). This tell >us nothing about what it would to without them. > >Can you turn the engame database off and try again? > > > Christophe Genius3 finds the solution without endgame table bases in a similiar time. It ran in pentium200 mmx under windows using only 384kbytes. the originial problem was this: 6k1/3K2Pp/2N5/3p3P/8/4b3/p3Q3/6q1 white begin and win The solution is 1.h6 Qxg7+ 2.Ne7+(this move is difficult for computers) 2...Qxe7 3.kxe7 a1=Queen(Bg5+ is probably the best move to survive one move more) 4.Qg4+ Bg5 5.Q:g5+ Kh8
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