Author: Paulo Soares
Date: 02:22:37 04/21/99
Go up one level in this thread
On April 20, 1999 at 21:44:00, Dave Gomboc wrote: >Here's a "real position", that is, one that has actually been reached in games. >It is from the Marshall Gambit in the Ruy Lopez. > >[Event "?"] >[Site "?"] >[Date "?"] >[Round "-"] >[White "?"] >[Black "?"] >[Result "*"] > >1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. >c3 d5 9. exd5 Nxd5 10. Nxe5 Nxe5 11. Rxe5 c6 12. d4 Bd6 13. Re1 Qh4 14. g3 >Qh3 15. Be3 Bg4 16. Qd3 Rae8 17. Nd2 Re6 18. a4 f5 19. Qf1 Qh5 20. f4 bxa4 >21. Rxa4 Rb8 22. Bxd5 cxd5 23. Qg2 Qe8 24. Qxd5 Kh8 25. Kf2 g5 26. Rxa6 >Rxb2 27. Ra2 gxf4 28. gxf4 Rxa2 29. Qxa2 Bxf4 30. Nf1 Qe7 * > >Now, White can (and I think should) play 31. Qxe6 here. What is Black's best >response? Well, if 31...Qh4+ leads to perpetual, then it is best, otherwise >31...Qxe6 will probably have to do. > >Rebel 9 (PII-300) thinks the position after 31...Qh4+ is +3.xx after under a >second, and holds this score for at least 5 minutes. It's main line is Qh4+ Kg1 >Bxh2 Nxh2 Qg3+ Kh1 Qxe1+ Kg2 ... > > >Crafty 16.6 (dual PII-300) appears to think that the position is a draw: > >max threads set to 2 >display PV each time it changes. >display statistics at end of each search. >display extended statistics at end of each search. >display move numbers in variations. >hash table memory = 48M bytes. >pawn hash table memory = 4M bytes. > >Crafty v16.6 (2 cpus) > >White(1): read test.pgn >middle-game phase > puzzling over a move to ponder. > clearing hash tables > depth time score variation (1) >starting thread 1 > 4-> 0.09 0.99 31. Qxe6 Qxe6 32. Bxf4 Qd5 > 5 0.11 1.03 31. Qxe6 Qxe6 32. Bxf4 Qc4 33. Re3 > 5-> 0.30 1.03 31. Qxe6 Qxe6 32. Bxf4 Qc4 33. Re3 > 6 0.33 1.10 31. Qxe6 Qxe6 32. Bxf4 Qc4 33. Re8+ > Kg7 34. Re7+ Kf6 > 6-> 0.59 1.10 31. Qxe6 Qxe6 32. Bxf4 Qc4 33. Re8+ > Kg7 34. Re7+ Kf6 > 7 0.76 1.02 31. Qxe6 Qxe6 32. Bxf4 Qc4 33. Re3 > Qa2+ 34. Ke1 Qc2 > 7-> 2.28 1.02 31. Qxe6 Qxe6 32. Bxf4 Qc4 33. Re3 > Qa2+ 34. Ke1 Qc2 > 8 2.55 0.98 31. Qxe6 Qxe6 32. Bxf4 Qc4 33. Re3 > Kg8 34. h3 Bd1 >White(31): Qxe6 [pondering] > clearing hash tables > time surplus 0.00 time limit 30.00 (3:00) [easy move] > depth time score variation (1) > 5-> 0.09 -1.10 31. ... Qxe6 32. Bxf4 Qc4 33. Re8+ > Kg7 34. Re7+ Kf6 > 6 0.12 -1.02 31. ... Qxe6 32. Bxf4 Qc4 33. Re3 Qa2+ > 34. Ke1 Qc2 > 6-> 0.31 -1.02 31. ... Qxe6 32. Bxf4 Qc4 33. Re3 Qa2+ > 34. Ke1 Qc2 > 7 0.37 -0.98 31. ... Qxe6 32. Bxf4 Qc4 33. Re3 Kg8 > 34. h3 Bd1 > 7-> 0.62 -0.98 31. ... Qxe6 32. Bxf4 Qc4 33. Re3 Kg8 > 34. h3 Bd1 > 8 1.30 -1.22 31. ... Qxe6 32. Bxf4 Qb3 33. Re3 Qc2+ > 34. Kg1 Be2 35. Re8+ Kg7 36. Ng3 Qd1+ > 37. Kg2 > 8 3.50 ++ 31. ... Qh4+!! > 8 3.59 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > 8-> 4.01 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > 9 5.08 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > 9-> 5.80 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > 10 8.86 -- 31. ... Qh4+ > 10 31.34 ++ 31. ... Qh4+!! > 10 31.36 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > <HT> > 10-> 33.06 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > <HT> > 11 37.37 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > 11-> 40.87 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > 12 1:00 -- 31. ... Qh4+ > 12 4:37 ++ 31. ... Qh4+!! > 12 4:37 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > <HT> > 12-> 4:48 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > <HT> > 13 5:30 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > 13-> 5:48 0.00 31. ... Qh4+ 32. Kg2 Qh3+ 33. Kf2 Qh4+ > 14 7:51 -- 31. ... Qh4+ >White(31): quit >execution complete. > >[I typed in quit when the time count was past 30 minutes. It had not yet >resolved the 14th ply.] > >I am not very good with operating crafty from the command line: I could not tell >it to "go to infinite time control mode and think on a move". But it seems like >this ponder search should be sufficient. > >Anyway, once I get to the position after Qh4+, Crafty decides to play 32. Kg1 in >under 3 seconds, with a large score (> 3 pawns). So why was it taking so long >to see this in the ponder search? I am not sure if it is a symptom of a search >going haywire, or merely a run-of-the-mill bug. :/ > >How do other programs handle this position? Oh, and could someone on the crafty >email list please post this there for Bob, since he doesn't seem to be around on >CCC anymore. > >Dave Dave, Fritz5.32, Genius6 and Hiarcs7.01 chooses 31. ...Qxe6 as its main move. their analyses are seemed to Rebel9 and Crafty after 31. ...Qh4+. I, in the style manmachine, deepened the analyses for 31. ...Qh4+, and I think that does not exist a perpetual check. In my opinion blacks loses after.31. ...Qh4+, even so the analyses are very complex, I would need a "truck full of variants" to prove that. 31. ...Bg6, it's a move that deserves attention. Best move in this position? It's difficult, but I would be with 31. ...Qxe6. Regards, Paulo Soares, from Brazil
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