Author: Slater Wold
Date: 19:49:28 03/22/04
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.)
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