Author: Slater Wold
Date: 05:57:03 10/20/01
Go up one level in this thread
On October 20, 2001 at 05:10:13, Simon Finn wrote: >On October 18, 2001 at 23:34:45, Slater Wold wrote: > >>On October 18, 2001 at 22:55:02, Dann Corbit wrote: >> >>>On October 18, 2001 at 21:01:46, Slater Wold wrote: >>> >>>>On October 18, 2001 at 09:14:43, José Antônio Fabiano Mendes wrote: >>>> >>>>> L.D.Evans-Haik,London 1978 [unusual and difficult position] >>>>> [D]8/p2P3P/k7/8/8/2q5/6PK/1Q6 b >>>>> "Surprisingly Black can deliver perpetual check or force stalemate." > >I'm not sure if this is literally true - I think White can force a drawn KQPKQP >endgame instead. > >>>>> Source:"Tactical Chess Endings",by GM John Nunn,page 35 >>>> >>>>Talk about a bummer.............. >>>> >>>>EPD Kit revision date: 1996.04.21 >>>>found computer opening book file [./bookc.bin]. >>>>max threads set to 2 >>>>hash table memory = 768M bytes. >>>>pawn hash table memory = 40M bytes. >>>>EGTB cache memory = 32M bytes. >>>>6 piece tablebase files found >>>>26330kb of RAM used for TB indices and decompression tables >>>>choose from 2 best moves. >>>> >>>> >>>>Crafty v18.12 (2 cpus) >>>> >>>>White(1): st 3600 >>>>search time set to 3600.00. >>>>White(1): epdpfga drawtest.epd drawtest.out >>>>PFGA: EPD record: 1 >>>>end-game phase >>>> clearing hash tables >>>> time surplus 0.00 time limit 60:00 (60:00) >>>> nss depth time score variation (1) >>>>starting thread 1 >>>> 7 0.14 6.02 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kg5 Qd2+ 6. Kh5 Qd4 >>>> 7. Qg6+ Kb7 8. g4 >>>> 7-> 0.16 6.02 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kg5 Qd2+ 6. Kh5 Qd4 >>>> 7. Qg6+ Kb7 8. g4 >>>> 8 0.29 5.92 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kg5 Qe3+ 6. Kf6 Qd4+ >>>> 7. Ke6 Qc4+ 8. Ke5 Qc7+ 9. Ke6 Qd8 >>>> 8-> 0.33 5.92 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kg5 Qe3+ 6. Kf6 Qd4+ >>>> 7. Ke6 Qc4+ 8. Ke5 Qc7+ 9. Ke6 Qd8 >>>> 9 0.63 5.92 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kg5 Qe3+ 6. Kf6 Qd4+ >>>> 7. Ke6 Qc4+ 8. Ke5 Qc3+ 9. Kd5 Qa5+ >>>> 10. Ke6 Qd8 >>>> 9-> 0.72 5.92 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kg5 Qe3+ 6. Kf6 Qd4+ >>>> 7. Ke6 Qc4+ 8. Ke5 Qc3+ 9. Kd5 Qa5+ >>>> 10. Ke6 Qd8 >>>> 10 1.24 5.82 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kf3 Qc3+ 6. Kf4 Qd2+ >>>> 7. Ke5 Qc3+ 8. Ke6 Qc4+ 9. Ke5 Qc5+ >>>> 10. Kf4 Qd6+ 11. Kf3 Qa3+ <HT> >>>> 10-> 1.33 5.82 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kf3 Qc3+ 6. Kf4 Qd2+ >>>> 7. Ke5 Qc3+ 8. Ke6 Qc4+ 9. Ke5 Qc5+ >>>> 10. Kf4 Qd6+ 11. Kf3 Qa3+ <HT> >>>> 11 2.30 5.82 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kf3 Qc3+ 6. Kf4 Qd2+ >>>> 7. Ke5 Qc3+ 8. Ke6 Qc4+ <HT> >>>> 11-> 2.71 5.82 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kf3 Qc3+ 6. Kf4 Qd2+ >>>> 7. Ke5 Qc3+ 8. Ke6 Qc4+ <HT> >>>> 12 5.02 5.82 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kf3 Qc3+ 6. Kf4 Qd2+ >>>> 7. Ke5 Qc3+ 8. Kd5 Qd2+ 9. Ke6 Qe3+ >>>> 10. Kf6 Qd4+ <HT> >>>> 12-> 5.50 5.82 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kg4 Qd4+ 5. Kf3 Qc3+ 6. Kf4 Qd2+ >>>> 7. Ke5 Qc3+ 8. Kd5 Qd2+ 9. Ke6 Qe3+ >>>> 10. Kf6 Qd4+ <HT> >>>> 13 7.79 ++ 1. ... Qe5+!! >>>> 13 13.49 4.22 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kh4 Qe7+ 5. Kh5 Qc5+ 6. Kh6 Qf8+ >>>> 7. Kg5 Qe7+ 8. Kf4 Qd6+ 9. Ke3 Qg3+ >>>> 10. Kd2 Qxg2+ 11. Ke3 Qg3+ 12. Kd4 >>>> Qd6+ 13. Kc4 Qc7+ 14. Kb4 Qd8 >>>> 13-> 14.55 4.22 1. ... Qe5+ 2. Kh3 Qh5+ 3. Kg3 Qe5+ >>>> 4. Kh4 Qe7+ 5. Kh5 Qc5+ 6. Kh6 Qf8+ >>>> 7. Kg5 Qe7+ 8. Kf4 Qd6+ 9. Ke3 Qg3+ >>>> 10. Kd2 Qxg2+ 11. Ke3 Qg3+ 12. Kd4 >>>> Qd6+ 13. Kc4 Qc7+ 14. Kb4 Qd8 >>>> 14 25.82 ++ 1. ... Qe5+!! >>>> 14 27.55 2.00 1. ... Qe5+ 2. Kh3 Qe6+ 3. g4 Qe3+ >>>> 4. Kh2 Qf4+ 5. Kg2 Qxg4+ 6. Kf2 Qf4+ >>>> 7. Ke2 Qg4+ 8. Ke3 Qg3+ 9. Kd4 Qd6+ >>>> 10. Ke4 Qb4+ 11. Kd5 Qxb1 12. h8=Q >>>> Qa2+ 13. Kc6 Qc2+ 14. Kd6 >>>> 14-> 29.02 2.00 1. ... Qe5+ 2. Kh3 Qe6+ 3. g4 Qe3+ >>>> 4. Kh2 Qf4+ 5. Kg2 Qxg4+ 6. Kf2 Qf4+ >>>> 7. Ke2 Qg4+ 8. Ke3 Qg3+ 9. Kd4 Qd6+ >>>> 10. Ke4 Qb4+ 11. Kd5 Qxb1 12. h8=Q >>>> Qa2+ 13. Kc6 Qc2+ 14. Kd6 >>>> 15 32.80 2.00 1. ... Qe5+ 2. Kh3 Qe6+ 3. g4 Qe3+ >>>> 4. Kh2 Qf4+ 5. Kg2 Qxg4+ 6. Kf2 Qf4+ >>>> 7. Ke2 Qg4+ 8. Ke3 Qg3+ 9. Kd4 Qd6+ >>>> 10. Ke4 Qb4+ 11. Kd5 Qxb1 12. h8=Q >>>> Qa2+ 13. Kd6 Qd2+ 14. Kc7 Qc2+ <HT> >>>> 15-> 34.79 2.00 1. ... Qe5+ 2. Kh3 Qe6+ 3. g4 Qe3+ >>>> 4. Kh2 Qf4+ 5. Kg2 Qxg4+ 6. Kf2 Qf4+ >>>> 7. Ke2 Qg4+ 8. Ke3 Qg3+ 9. Kd4 Qd6+ >>>> 10. Ke4 Qb4+ 11. Kd5 Qxb1 12. h8=Q >>>> Qa2+ 13. Kd6 Qd2+ 14. Kc7 Qc2+ <HT> >>>> 16 46.88 -- 1. ... Qe5+ >>>> time=60:01 cpu=201% mat=2 n=1693306751 fh=99% nps=470k >>>> ext-> chk=1363197943 cap=274706 pp=267447 1rep=117221890 mate=2380 >>>> >>>> predicted=0 nodes=1693306751 evals=7323296 >>>> endgame tablebase-> probes done=48149 successful=4738 >>>> hashing-> trans/ref=73% pawn=99% used=14% >>>> SMP-> split=4869 stop=472 data=13/32 cpu=120:40 elap=60:01 >>>>Black(1): >>>> >>>> >>>>Fails low @ 46 seconds, and can't resolve it in 59 minutes. :( >>> >>>This looks like a bug. That position should never fail low, but always fail >>>high. > >Why? The position is ultimately drawn, but that doesn't mean there won't be some >nasty shocks on the way. > >>> >>>Either that, or crafty may have found some strange, suicidal attack that >>>succeeds. >> >>If I had to guess, I'd say it'll find something. I did it with 10 minutes at >>first, and it did this same thing. 59 minutes to resolve a fail low _does_ seem >>a tad long. Perhaps Bob can help here. > >I had a long look at this position yesterday. > >White will win if he can get his king to a1 - this allows him to >interpose the queen and eventually kill the checks. > >To prevent this, Black has to answer Ka2 with Qa4+/Qa5+ and Kb2 with Qd4+/e5+. > >This requirement restricts where Black can check when the White king is on other >squares too. > >I think (but I'm not 100% sure) that answering Ke3 with Qg3+ loses >because the White king can eventually get to a1. > >Crafty may just have discovered this and needs to spend a >lot of time finding an alternative system of defence that works. >(Black should arrange things to answer Ke3 with Qc5+, for example.) > >Simon > >> >>I can give it more time, if requested. That's a very good explaination. However, after about 54 billion nodes, I would expect it to have exhausted all of these possibilities. :)
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