interesting "null move killer" position

Discussion of anything and everything relating to chess playing software and machines.

Moderator: Ras

CRoberson
Posts: 2094
Joined: Mon Mar 13, 2006 2:31 am
Location: North Carolina, USA

Re: interesting "null move killer" position

Post by CRoberson »

Telepath 4.43 finds Qb8 in 0 secs in 4 ply.
No null move verification search.
It does re-search any LMR searches that exceed alpha.
Top
User avatar
smrf
Posts: 484
Joined: Mon Mar 13, 2006 11:08 am
Location: Klein-Gerau, Germany

Re: interesting "null move killer" position

Post by smrf »

SMIRF does a prefiltered 0-move. But when it does a 0-move, this does not need to be verified, because its designed 0-move method is without any bad zugzwang payload (nevertheless deprecated SMIRF probably is not free of bugs). SMIRF normally still is very slow compared to leading engines, but here it seems to work fine:

06:15.4 (19.01=) +3.453 1.Qb8 (=/=) Qxa2 2.Bxc5 Qxb3 3.Qxf8+ Kh7 4.Qxf7 Qxc4 5.Bf8 Qe4+ 6.Kh2 Qxe5 7.Bxb4 Qd4 8.Qg6+ Kh8
03:15.6 (18.01=) +3.498 1.Qb8 (=/=) Qxa2 2.Bxc5 Qxb3 3.Qxf8+ Kh7 4.Qxf7 Qxc4 5.Bf8 Qe4+ 6.Kh2 Qxe5 7.Bxb4 Qxg3+ 8.Kxg3 Kh8
01:01.8 (17.01=) +3.639 1.Qb8 (=/=) Qxa2 2.Bxc5 Qxb3 3.Qxf8+ Kh7 4.Qxf7 Qxc4 5.Bf8 Qe4+ 6.Kh2 Qxe5 7.Bxb4 Qxg3+ 8.Kxg3 Kh8
00:30.3 (16.01=) +3.697 1.Qb8 (=/=) Qxa2 2.Bxc5 Qxb3 3.Qxf8+ Kh7 4.Qxf7 Qxc4 5.Bf8 Qe4+ 6.Kh2 Qxe5 7.Bxb4 Qxg3+ 8.Kxg3 Kh8
00:14.3 (15.01=) +3.500 1.Qb8 (=/=) Qxa2 2.Bxc5 Qxb3 3.Qxf8+ Kh7 4.Qxf7 Qxc4 5.Bf8 Qe4+ 6.Kh2 Qxe5 7.Bxb4 Qxg3+ 8.Kxg3 Kh8
00:08.3 (14.01=) +3.500 1.Qb8 (=/=) Qxa2 2.Bxc5 Qxb3 3.Qxf8+ Kh7 4.Qxf7 Qxc4 5.Bf8 Qe4+ 6.Kh2 Qxe5 7.Bxb4 Qxg3+ 8.Kxg3 Kh8
00:05.1 (13.01=) +3.500 1.Qb8 (=/=) Qxa2 2.Bxc5 Qxb3 3.Qxf8+ Kh7 4.Qxf7 Qxc4 5.Bf8 Qe4+ 6.Kh2 Qxe5 7.Bxb4 Qxg3+ 8.Kxg3 Kh8
00:03.3 (12.01=) +3.453 1.Qb8 (=/=) Qxa2 2.Bxc5 Qxb3 3.Qxf8+ Kh7 4.Qxf7 Qxc4 5.Qg6+ Kh8 6.Qe8+ Kh7 7.Qf8 Qe4+ 8.f3 Qe2+
00:01.9 (11.01=) +3.645 1.Qb8 (=/=) f6 2.exf6 Kf7 3.fxg7 Bxg7 4.Qb7+ Kg8 5.Qc8+ Kh7 6.Qxe6 Qxa2 7.Qg6+ Kg8 8.Bxh6 Qxf2+
00:01.4 (10.01=) +3.365 1.Qb8 (=/=) f6 2.exf6 Kf7 3.fxg7 Kxg7 4.Qb7+ Kg8 5.Qd7 Qb6 6.Bg5
00:01.2 (10.01+) +2.494 1.Qb8 (=/=) f6 2.exf6 Kf7 3.fxg7 Kxg7 4.Qb7+ Kg8 5.Qd7 Qxa2 6.Qxe6+ Kh8
00:00.7 (09.01=) +3.365 1.Qb8 (=/=) f6 2.exf6 Kf7 3.fxg7 Kxg7 4.Qb7+ Kg8 5.Qd7 Qxa2 6.Qxe6+ Kh8
00:00.6 (09.01+) +2.180 1.Qb8 (=/=) f6 2.exf6 Kf7 3.fxg7 Kxg7 4.Qb7+ Kg8 5.Qd7 Qxa2 6.Qxe6+ Kh8
00:00.5 (08.01=) +3.051 1.Qb8 (=/=) f6 2.exf6 Kf7 3.fxg7 Bxg7 4.Qb7+ Kf8 5.Qe7+ Kxe7 6.Bxc5+ Qxc5 7.f4
00:00.3 (08.00-) +2.164 1.Qb8 (=/=) f6 2.exf6 Kf7 3.fxg7 Bxg7 4.Qb7+ Kf8 5.Qf7+ Kxf7 6.Bxh6
00:00.2 (07.01=) +3.051 1.Qb8 (=/=) f6 2.exf6 Kf7 3.fxg7 Bxg7 4.Qb7+ Kf8 5.Qf7+ Kxf7 6.Bxh6
00:00.1 (07.00-) +1.807 1.Qb8 (=/=) f6 2.exf6 gxf6 3.Qxf8+ Kxf8 4.Bxc5+ Kf7 5.Bxb4
00:00.0 (05.01=) +1.994 1.Qb8 (g4) f6 2.exf6 gxf6 3.Bxh6 Qxa2 4.Qxf8+ Kh7 5.Qg7#
Top
Will Singleton
Posts: 128
Joined: Thu Mar 09, 2006 5:14 pm
Location: Los Angeles, CA

Re: interesting "null move killer" position

Post by Will Singleton »

Just another data point, Amateur finds it in 3 secs, no null verification. Probably something else going on here.

12 86 151 723588 Kf3 Qb6 g4 a5
12 363 282 1403991 Qb8 f6 exf6 Kf7 fxg7 Bxg7 Qa7 Kg8 Qxc5 Qxc5 Bxc5 Bc3 Kf3
13 364 338 1698570 Qb8 f6 exf6 Kf7 fxg7 Bxg7 Qa7 Kg8 Qe7 Kh7 Qxc5 Qxc5 Bxc5 Bc3
Top
User avatar
smirobth
Posts: 2307
Joined: Wed Mar 08, 2006 8:41 pm
Location: Brownsville Texas USA

Re: interesting "null move killer" position

Post by smirobth »

Uri Blass wrote:
José Carlos wrote:Are you sure this position is a null move killer? Averno gets it instantly, and Averno is anything but good in null move killer positions.
I think that it is dependent on the program.

Qb8 is a move that may have threat or not have threat dependent on the evaluation.

If it has a threat you do not prune it so you find it regardless of verification.
If it has no threat then you prune it and you never find it if you do not do verfication.

Uri
On b8 the only thing the queen does that it was not already doing from c8 is guarding the b6 square. I can't see any way that Qb8 involves a threat, other than putting Black in zugszwang.
- Robin Smith
Top
User avatar
Zach Wegner
Posts: 1922
Joined: Thu Mar 09, 2006 12:51 am
Location: Earth

Re: interesting "null move killer" position

Post by Zach Wegner »

jdart wrote:A position with a fair amount of material where null move can malfunction:

[d] 2Q2bk1/5pp1/p3p2p/q1p1P2P/1pP5/1P2B1P1/P4PK1/8 w - - 0 1

bm is Qb8. This actually occurred in an offline game. Arasan 10.1 does ok on this but my latest build has trouble, for some reason.

--Jon
I left ZCT analyzing while I was at school. On a dual 1.25 GHz G4/64M ram, it got the solution in .114 seconds. I use infinite null move, i.e. it can do several null moves in a row. I noticed that I had debug mode on just now, and when I turn it off it gets .052 seconds. I win!!!

Code: Select all

(zct)1. analyze
Depth          Time     Score   PV (nodes)
  1/ 2        0.001     -3.67   1. a3 bxa3 (3)
  1/ 7        0.028     -1.97   1. f3 Qxa2+ 2. Kh3 Qxb3 3. Bxc5 (39)
  1/ 7        0.034     -0.66   1. g4 (46)
[ 1/ 7]       0.039     -0.66   1. g4 (86)
  2/ 7        0.042     -0.56   1. g4 Qb6 (125)
[ 2/ 7]       0.059     -0.56   1. g4 Qb6 (421)
  3/ 8        0.068     -0.55   1. g4 Qb6 2. Kf3 (559)
  3/ 8        0.114     -0.23   1. Qb8 Qxa2 2. Bxc5 (1018)
[ 3/ 8]       0.126     -0.23   1. Qb8 Qxa2 2. Bxc5 (1221)
  4/10        0.162     +0.09   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 (2168)
[ 4/10]       0.176     +0.09   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 (2505)
  5/12        0.255     +1.04   1. Qb8 g5 2. hxg6 fxg6 3. Bxh6 (4782)
[ 5/12]       0.275     +1.04   1. Qb8 g5 2. hxg6 fxg6 3. Bxh6 (5321)
  6/14        0.407     +1.62   1. Qb8 g5 2. hxg6 fxg6 3. Bxh6 Qxa2 4. Qxf8+ Kh7 5. Qg7# (9599)
[ 6/14]       0.449     +1.62   1. Qb8 g5 2. hxg6 fxg6 3. Bxh6 Qxa2 4. Qxf8+ Kh7 5. Qg7# (10771)
  7/15        0.650     +2.09   1. Qb8 g5 2. hxg6 fxg6 3. Bxh6 Kh7 4. Bxf8 Qxa2 5. Bxc5 (17466)
[ 7/15]       0.757     +2.09   1. Qb8 g5 2. hxg6 fxg6 3. Bxh6 Kh7 4. Bxf8 Qxa2 5. Bxc5 (19644)
  8/18        0.973     +2.09   1. Qb8 g5 2. hxg6 Kg7 3. Bxh6+ Kxh6 4. Qxf8+ Kxg6 5. Qg8+ Kf5 6. Qxf7+ (27195)
[ 8/18]       1.189     +2.09   1. Qb8 g5 2. hxg6 Kg7 3. Bxh6+ Kxh6 4. Qxf8+ Kxg6 5. Qg8+ Kf5 6. Qxf7+ (33367)
  9/18        1.799     +2.15   1. Qb8 g5 2. hxg6 Kg7 3. Bxh6+ Kxh6 4. Qxf8+ Kxg6 5. Qg8+ Kh6 6. Qxf7 (60366)
[ 9/18]       2.157     +2.15   1. Qb8 g5 2. hxg6 Kg7 3. Bxh6+ Kxh6 4. Qxf8+ Kxg6 5. Qg8+ Kh6 6. Qxf7 (69063)
 10/21        3.675     +2.30   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Qe8+ Kh7 7. Qg6+ Kh8 8. Qe8+ Kh7 (139471)
[10/21]       3.934     +2.30   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Qe8+ Kh7 7. Qg6+ Kh8 8. Qe8+ Kh7 (150224)
 11/21        5.161     +2.30   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Qe8+ Kh7 (205156)
[11/21]       5.571     +2.30   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Qe8+ Kh7 (223109)
 12/24        7.346     +2.68   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 (304569)
[12/24]       8.136     +2.68   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 (337828)
 13/24       15.546     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 a5 9. Qe8+ Kh7 (716806)
[13/24]      16.849     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 a5 9. Qe8+ Kh7 (777357)
 14/24       21.390     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qb7 8. Qxe6 b3 9. Qg6 (993962)
[14/24]      25.203     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qb7 8. Qxe6 b3 9. Qg6 (1180477)
 15/27       31.210     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 Kg8 9. Qe8+ Kh7 (1479637)
[15/27]      34.845     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 Kg8 9. Qe8+ Kh7 (1662725)
 16/27       49.859     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 a5 9. Qe8+ Kh7 (2426319)
[16/27]      55.209     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 a5 9. Qe8+ Kh7 (2703985)
 17/28         1:19     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 a5 9. Qe8+ Kh7 10. Qg6+ Kh8 (3951063)
[17/28]        1:29     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Bf8 Qd5+ 7. Kh2 Qxe5 8. Bxb4 a5 9. Qe8+ Kh7 10. Qg6+ Kh8 (4438583)
 18/30         2:16     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Qe8+ Kh7 7. Qg6+ (6884374)
[18/30]        2:31     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Qe8+ Kh7 7. Qg6+ (7657211)
 19/30         3:35     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Qe8+ Kh7 7. Qg6+ (10990143)
[19/30]        4:07     +2.93   1. Qb8 Qxa2 2. Bxc5 Qxb3 3. Qxf8+ Kh7 4. Qxf7 Qxc4 5. Qg6+ Kh8 6. Qe8+ Kh7 7. Qg6+ (12660046)
 20/39        26:37     +3.83   1. Qb8 Qxa2 2. Bxc5 Kh7 3. Qxf8 Qc2 4. Bxb4 Qe4+ (83481421)
[20/39]       27:48     +3.83   1. Qb8 Qxa2 2. Bxc5 Kh7 3. Qxf8 Qc2 4. Bxb4 Qe4+ (87170400)
 21/41      2:45:54     +5.00   1. Qb8 f5 2. exf6 Kf7 3. fxg7 Bxg7 4. Qb7+ Kg8 5. Qc8+ Kh7 6. Qxe6 Qxa2 7. Bxh6 Bc3 8. Qf5+ Kg8 9. Qxc5 Qxb3 10. Qd5+ Kh7 11. Qe4+ Kg8 12. Qa8+ Kh7 13. Qe4+ Kg8 14. Qg4+ Kh7 (523390086)
[21/41]     2:49:41     +5.00   1. Qb8 f5 2. exf6 Kf7 3. fxg7 Bxg7 4. Qb7+ Kg8 5. Qc8+ Kh7 6. Qxe6 Qxa2 7. Bxh6 Bc3 8. Qf5+ Kg8 9. Qxc5 Qxb3 10. Qd5+ Kh7 11. Qe4+ Kg8 12. Qa8+ Kh7 13. Qe4+ Kg8 14. Qg4+ Kh7 (535069130)
 22/42      3:19:36     +5.01   1. Qb8 f5 2. exf6 Kf7 3. fxg7 Bxg7 4. Qb7+ Kg8 5. Qc8+ Kh7 6. Qxe6 Qxa2 7. Bxh6 Bc3 8. Qf5+ Kg8 9. Qxc5 Qxb3 10. Qd5+ Kh7 11. Qe4+ Kg8 12. Qe6+ Kh7 (629562329)
[22/42]     3:25:02     +5.01   1. Qb8 f5 2. exf6 Kf7 3. fxg7 Bxg7 4. Qb7+ Kg8 5. Qc8+ Kh7 6. Qxe6 Qxa2 7. Bxh6 Bc3 8. Qf5+ Kg8 9. Qxc5 Qxb3 10. Qd5+ Kh7 11. Qe4+ Kg8 12. Qe6+ Kh7 (646395575)
Top

Return to “Computer Chess Club: General Topics”