Author: Uri Blass
Date: 15:01:31 03/23/04
Go up one level in this thread
On March 22, 2004 at 22:49:28, Slater Wold wrote: >Dann recently posted an EPD of 'questionable' positions, he was researching. >One of those positions is this: > >[D]7b/8/kq6/8/8/1N2R3/K2P4/8 w - - > >The move to make is Nd4. > > >With null move on, Crafty 19.11 cannot find it after an hour on my FX51. With >null move off, it cannot find it in 2+ hours. > > >end-game phase > clearing hash tables > time surplus 0.00 time limit 150:00 (150:00) > depth time score variation (1) > 6-> 0.60 -4.59 1. Rh3 Be5 2. Rh4 Bc3 3. d4 Kb5 > 7 1.13 -4.68 1. Rh3 Qf6 2. Ka3 Kb6 3. Re3 Qd6+ 4. > Ka4 Be5 > 7-> 1.77 -4.68 1. Rh3 Qf6 2. Ka3 Kb6 3. Re3 Qd6+ 4. > Ka4 Be5 > 8 3.02 -4.70 1. Rh3 Bf6 2. Rh5 Qb4 3. Ra5+ Kb6 4. > Ra8 Qc4 5. Ka3 > 8 4.10 -4.69 1. Re8 Bf6 2. Rc8 Kb5 3. Rc2 Kb4 4. > Nc5 Bd4 > 8-> 4.32 -4.69 1. Re8 Bf6 2. Rc8 Kb5 3. Rc2 Kb4 4. > Nc5 Bd4 > 9 7.25 -4.79 1. Re8 Bf6 2. Rc8 Kb5 3. Ra8 Kc4 4. > Rc8+ Kd3 5. Re8 Qb4 > 9-> 10.57 -4.79 1. Re8 Bf6 2. Rc8 Kb5 3. Ra8 Kc4 4. > Rc8+ Kd3 5. Re8 Qb4 > 10 17.03 -- 1. Re8 > 10 18.78 -5.19 1. Re8 Bg7 2. Re1 Qc6 3. Ka3 Kb5 4. > d4 Qd6+ 5. Kb2 Bxd4+ 6. Kc2 Ka4 > 10 26.66 -4.99 1. Rh3 Bf6 2. Re3 Kb5 3. Kb1 Qc6 4. > Re2 Kb4 5. Re3 <HT> > 10-> 27.91 -4.99 1. Rh3 Bf6 2. Re3 Kb5 3. Kb1 Qc6 4. > Re2 Kb4 5. Re3 <HT> > 11 49.75 -5.04 1. Rh3 Bf6 2. Re3 Kb5 3. Kb1 Qc6 4. > Re2 Qh1+ 5. Kc2 Qh7+ 6. d3 Qc7+ 7. > Kb1 Bc3 > 11-> 54.22 -5.04 1. Rh3 Bf6 2. Re3 Kb5 3. Kb1 Qc6 4. > Re2 Qh1+ 5. Kc2 Qh7+ 6. d3 Qc7+ 7. > Kb1 Bc3 > 12 1:37 -5.19 1. Rh3 Bg7 2. Rg3 Bf6 3. Re3 Kb5 4. > Kb1 Qd6 5. Rf3 Qe5 6. Rc3 Qe6 7. d4 > Qe4+ <HT> > 12-> 1:44 -5.19 1. Rh3 Bg7 2. Rg3 Bf6 3. Re3 Kb5 4. > Kb1 Qd6 5. Rf3 Qe5 6. Rc3 Qe6 7. d4 > Qe4+ <HT> > 13 4:10 -5.19 1. Rh3 Bg7 2. Rh5 Qc6 3. Ra5+ Kb6 4. > Ka3 Qc2 5. Rc5 Bb2+ 6. Kb4 Qd3 7. Rg5 > Qe4+ 8. d4 Bxd4 > 13-> 4:24 -5.19 1. Rh3 Bg7 2. Rh5 Qc6 3. Ra5+ Kb6 4. > Ka3 Qc2 5. Rc5 Bb2+ 6. Kb4 Qd3 7. Rg5 > Qe4+ 8. d4 Bxd4 > 14 10:21 -5.40 1. Rh3 Bg7 2. Rd3 Kb5 3. Nc1 Qe6+ 4. > Rb3+ Ka4 5. Kb1 Qf5+ 6. d3 Qc8 7. Rb6 > Bd4 8. Rh6 Qb7+ 9. Kc2 Kb5 > 14-> 25:19 -5.40 1. Rh3 Bg7 2. Rd3 Kb5 3. Nc1 Qe6+ 4. > Rb3+ Ka4 5. Kb1 Qf5+ 6. d3 Qc8 7. Rb6 > Bd4 8. Rh6 Qb7+ 9. Kc2 Kb5 > 15 43:02 -5.46 1. Rh3 Bg7 2. Rd3 Kb5 3. Nc1 Qe6+ 4. > Rb3+ Ka4 5. Kb1 Qf5+ 6. d3 Qc8 7. Rb6 > Bd4 8. Rh6 Qb7+ 9. Kc2 Qc7+ 10. Kb1 > Kb5 > 15-> 52:27 -5.46 1. Rh3 Bg7 2. Rd3 Kb5 3. Nc1 Qe6+ 4. > Rb3+ Ka4 5. Kb1 Qf5+ 6. d3 Qc8 7. Rb6 > Bd4 8. Rh6 Qb7+ 9. Kc2 Qc7+ 10. Kb1 > Kb5 >? 16 123:15 1/21* 1. Rh3 >White(1): ? > time=123:18 cpu=93% mat=-3 n=15825753814 fh=91% nps=2.14M > ext-> chk=2036926939 cap=8454776 pp=165049 1rep=64992669 mate=0 > predicted=0 nodes=15825753814 evals=2468248106 50move=0 > endgame tablebase-> probes=22280432 hits=5113019 > hashing-> 410%(raw) 408%(depth) -70%(sat) 99%(pawn) > hashing-> 22%(exact) 339%(lower) 38%(upper) > >Now here comes the funny part: > >Black(1): undo >NOTICE: 60 moves to next time control >White(1): nd4 > time used: 5.63 > clearing hash tables >crafty is behind 32.0 on time, reducing by 1/96. > time surplus 0.00 time limit 150:00 (150:00) > depth time score variation (1) > 7-> 0.08 -6.19 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kd6 > 7. Rc2 > 8 0.08 ++ 1. ... Qxd4!! > 8-> 0.24 -6.58 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kd6 > 7. Rc2 > 9 0.24 -- 1. ... Qxd4 > 9 0.24 -5.89 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kd7 9. Rc2 > 9-> 1.39 -5.89 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kd7 9. Rc2 > 10 1.39 ++ 1. ... Qxd4!! > 10-> 4.05 -6.28 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kd7 9. Rc2 > 11 4.08 -- 1. ... Qxd4 > 11 4.08 -5.69 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rc2 > 11-> 18.13 -5.69 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rc2 > 12 18.14 ++ 1. ... Qxd4!! > 12-> 59.14 -6.08 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rc2 > 13 59.14 -- 1. ... Qxd4 > 13 59.14 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 13-> 1:09 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 14 1:10 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 14-> 1:18 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 15 1:18 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 15-> 1:21 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 16 1:22 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 16-> 1:41 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 17 1:41 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 17-> 1:53 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 18 1:53 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 18-> 2:41 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> > 19 2:42 -0.01 1. ... Qxd4 2. Ra3+ Kb5 3. Rb3+ Kc5 > 4. Rc3+ Kb6 5. Rb3+ Kc6 6. Rc3+ Kb7 > 7. Rb3+ Kc7 8. Rc3+ Kb8 9. Rb3+ Kc8 > 10. Rc3+ Kd8 11. Rd3 Qxd3 <EGTB> >? 19 2:45 2/26* 1. ... Qb2+ >Black(0): ? > time=2:48 cpu=59% mat=-3 n=242194480 fh=96% nps=1.44M > ext-> chk=20672785 cap=135325 pp=1837 1rep=655826 mate=0 > predicted=0 nodes=242194480 evals=74568494 50move=1 > endgame tablebase-> probes=517404 hits=397247 > hashing-> 49%(raw) 43%(depth) 78%(sat) 99%(pawn) > hashing-> 2%(exact) 31%(lower) 3%(upper) > > > >Undo the move, play Nd4, and it sees it's a draw, fairly quickly. > >So what keeps it from playing Nd4 in the first place. Not nullmove! It was >turned off. > >White(1): sel 0 0 >null move disabled. > > >Can any engine out there find Nd4 with a draw score? >Can anyone explain Crafty's behaviour here? (My guess is some sort of >symmetry.) Movei can find the move but not with a draw score. Unfortunately it does not know to evaluate KB vs KP as a draw so it evaluates it as a clear advantage for black. Uri
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