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Subject: Re: A case when Movei earn 2 plies from verified null move pruning

Author: Sune Fischer

Date: 15:57:06 11/22/02

On November 22, 2002 at 18:09:28, Uri Blass wrote:

>previous version found Rxb2 only at depth 14
>With verified null move pruning movei finds wac 2  at depth 12.
>
>[D]8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - 0 1
>
>depth=12 +0.64 b3b2
>Nodes: 6559172 NPS: 215975
>Time: 00:00:30.37
>
>depth=12 +2.67 b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7h6 b7b6 h6h5 b6b5 c3c2 b5f5 h5g6
>f5g5 g6h6 g5c5 d3d2 c5c6 h6h5 c6c5 h5h4 c5c2 d2d1q c2e2
>Nodes: 17674291 NPS: 212303
>Time: 00:01:23.25
>
>depth=13 +3.54 b3b2 d2b2 c4c3 b2b6 f6g7 b6b7 g7h6 b7b6 h6h5 b6b5 c3c2 b5f5 h5g6
>f5g5 g6f6 g5c5 d3d2 c5c6 f6e7 c6c7 e7d6 c7c2 d2d1q c2e2 h7h5
>Nodes: 30679118 NPS: 220032
>Time: 00:02:19.43
>
>Uri

In my program nullmove delays it 1 ply, but it is still found faster.
It seems to find it very early, for other reasons though.

with nullmove:

8	6	13	25569		1...c3 2.bxc3 Rxc3 3.e4 fxe4+ 4.Kxe4 Rc4+ 5.Kf3 Kf5 6.Rxd3 Rxf4+
7.Ke2 Rxd3
9	6	29	79390		1...c3 2.bxc3 Rxc3 3.e4 fxe4+ 4.Kxe4 Rc4+ 5.Ke3 Kf5 6.Rxd3 Rxf4
7.Rd6
9	5	68	234477		1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rc6 c2
10	0	260	990857		1...Rxb2 2.Rxb2 c3 3.Rb6+ Kg7 4.Rb7+ Kh6 5.Rb6+ Kg7
11	0	667	2526638		1...Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.Rb7+ Kf6 5.Rb6+ c2 Rh6
12	-185	2486	9262237		1...Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.Rb7+ Kg6 5.Rb6+ Kh5 6.Rb5
c2 7.Rxf5+ Kh4 8.Rf6 h5 9.Rc6 d2 10.Rxc2 d1=Q+

depth=13 -2.98 1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc5 6.Rb7 c2
7.Rxh7 d2 8.Rc7+ Kb5 9.Rxc2 d1=Q+ 10.Re2 Qa1 11.h4 Qxa3
Nodes: 21004067 NPS: 361515
Time: 00:00:58.10

Without nullmove:

9	6	187	648116		1...c3 2.bxc3 Rxc3 3.e4 fxe4+ 4.Kxe4 Rc4+ 5.Ke3 Kf5 6.Rxd3 Rxf4
7.Rd2
9	0	269	941513		1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Ke7
10	0	852	3026130		1...Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.Rb7+ Ke8 5.Rb8+ Kd7 6.Rb7+ Ke8
10	0	1915	6797363		1...Rb6 2.h3 Kf7
11	0	4999	17796924	1...Rb6 2.Rg2 Rb3 3.Rd2
11	-194	6172	21942629	1...Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6 5.Rb6+ Kc7 6.Rf6
c2 7.Rf7+ Kd8 8.Rxf5 c1=Q 9.Rd5+ Kc7 10.Rxd3

-S.

Re: A case when Movei earn 2 plies from verified null move pruning Uri Blass 16:16:59 11/22/02
- Re: A case when Movei earn 2 plies from verified null move pruning Sune Fischer 01:24:15 11/23/02
- Re: A case when Movei earn 2 plies from verified null move pruning Uri Blass 16:20:15 11/22/02
  - Re: A case when Movei earn 2 plies from verified null move pruning Uri Blass 16:21:56 11/22/02
    - Re: A case when Movei earn 2 plies from verified null move pruning Sune Fischer 01:27:07 11/23/02
      - Re: A case when Movei earn 2 plies from verified null move pruning Uri Blass 02:02:40 11/23/02
        
        Re: A case when Movei earn 2 plies from verified null move pruning Sune Fischer 02:45:19 11/23/02
        
        Re: A case when Movei earn 2 plies from verified null move pruning Uri Blass 02:48:25 11/23/02
        
        Re: A case when Movei earn 2 plies from verified null move pruning Sune Fischer 02:52:51 11/23/02
        
        Re: A case when Movei earn 2 plies from verified null move pruning Uri Blass 03:03:50 11/23/02
        
        Re: A case when Movei earn 2 plies from verified null move pruning Sune Fischer 03:15:27 11/23/02
        
        Re: A case when Movei earn 2 plies from verified null move pruning Sune Fischer 04:19:11 11/23/02
        
        Re: A case when Movei earn 2 plies from verified null move pruning Uri Blass 04:32:48 11/23/02

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