Neghina position

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ernest
Posts: 2041
Joined: Wed Mar 08, 2006 8:30 pm

Neghina position

Post by ernest »

I wonder what today's situation is for this 10-year old Neghina position (prison for Queen)
also seen in Eigenmann’s Der Brillante Schachzug 53

[d] 3k4/2pq3p/pp5R/4P3/P6P/2PN4/1PN3K1/8 w - - 0 1

Best move and win : Nd4
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MikeB
Posts: 4889
Joined: Thu Mar 09, 2006 6:34 am
Location: Pen Argyl, Pennsylvania

Re: Neghina position

Post by MikeB »

ernest wrote: ↑Mon Nov 25, 2019 3:33 am I wonder what today's situation is for this 10-year old Neghina position (prison for Queen)
also seen in Eigenmann’s Der Brillante Schachzug 53

[d] 3k4/2pq3p/pp5R/4P3/P6P/2PN4/1PN3K1/8 w - - 0 1

Best move and win : Nd4
May still be too hard -

but from this position , advancing 6 plies

[d]3k4/2p4p/1p5q/p3P3/P2N1N1P/2P4K/1P6/8 w - - 0 4
Honey XR7 ( soon to be released)

Code: Select all

dep	score	nodes	time	(not shown:  tbhits	knps	seldep)
 40	+5.36!	1.22G	0:33.28	Nde6+! 
 40	+5.17!	1.08G	0:29.74	Nde6+! 
 40	+5.03!	962.4M	0:26.63	Nde6+! 
 39	+4.89 	862.5M	0:24.00	Nde6+ Kc8 h5 c6 c4 b5 cxb5 cxb5 b3 Kb8 Kg3 Kb7 Kg4 Kb6 Kf3 Kb7 Ke4 Kc6 Kd4 b4 Ke4 Kb7 Kd5 Kb8 Kc5 Kc8 Kc6 Kb8 Kb6 Kc8 Kxa5 Kd7 Kxb4 Kc6 Ka5 Kb7 b4 Kc6 b5+ Kd7 Kb6 Ke8 Kc5 Kd7 
 39	+4.70!	734.0M	0:20.65	Nde6+! 
 39	+4.52!	667.8M	0:18.91	Nde6+! 
 39	+4.39!	592.9M	0:16.98	Nde6+! 
 38	+4.26 	515.6M	0:14.93	Nde6+ Kc8 h5 Kb7 Kg4 Kc8 c4 Kb7 Kh3 Kc8 Kg3 Kb8 Kf3 Kb7 Ke4 b5 axb5 Ka7 Kf5 Kb6 Kg4 Kb7 Kf3 Kb6 Ke3 Ka7 Ke4 Kb7 Kd5 Kb6 b3 a4 bxa4 Ka5 c5 Kxa4 b6 cxb6 cxb6 
 38	+4.09!	467.0M	0:13.59	Nde6+! 
 38	+3.66!	366.5M	0:10.72	Nde6+! 
 38	+3.32!	287.8M	0:08.56	Nde6+! 
 38	+3.07!	258.4M	0:07.77	Nde6+! 
 38	+2.88!	247.9M	0:07.46	Nde6+! 
 38	+2.73!	236.6M	0:07.14	Nde6+! 
 38	+2.63!	217.1M	0:06.64	Nde6+! 
 37	+2.53 	156.3M	0:04.87	Nde6+ Ke7 Kg3 c6 h5 Ke8 Kg4 Kd7 c4 b5 cxb5 cxb5 b3 Kc8 Kf3 Kd7 Ke4 Kc6 Kd4 Kb7 Kc5 bxa4 bxa4 Ka7 Kd4 Ka8 Kd5 Kb8 Kc6 Kc8 Kc5 Kb7 Kb5 Ka8 Kb6 
 37	+2.30!	143.7M	0:04.50	Nde6+! 
 37	+1.94!	138.8M	0:04.36	Nde6+! 
 37	+1.66!	138.1M	0:04.34	Nde6+! 
 37	+1.45!	137.4M	0:04.32	Nde6+! 
 37	+1.29!	134.7M	0:04.24	Nde6+! 
 37	+1.18!	119.5M	0:03.81	Nde6+! 
 37	+1.10!	111.4M	0:03.58	Nde6+! 
 36	+1.02 	92.4M  	0:03.04	Nde6+ Kc8 h5 c6 c4 Kb8 Kg4 Ka7 Kf3 Kb7 Kg2 Ka6 Kg3 Kb7 Kf3 Ka6 Ke4 Kb7 c5 bxc5 Nxc5+ Kb8 Nce6 Ka7 Kd4 Kb6 Kd3 c5 Ke4 Kc6 Ke3 Kb6 Kd3 Ka7 Ke4 Kb8 Kd5 Ka7 Kc6 c4 Kc5 Ka6 Kxc4 Kb6 Kd5 Kb7 
 35	+1.02 	82.4M  	0:02.74	Nde6+ Kc8 h5 c6 c4 Kb8 Kg4 Ka7 Kf3 Kb7 Kg2 Ka6 Kg3 Kb7 Kf3 Ka6 Ke4 Kb7 c5 bxc5 Nxc5+ Kb8 Nce6 Ka7 Kd4 Kb6 Kd3 c5 Ke4 Kc6 Ke3 Kb6 Kd3 Ka7 Ke4 Kb8 Kd5 Ka7 Kc6 c4 Kc5 
 34	+0.23 	64.5M  	0:02.21	Nde6+ Kc8 c4 Kd7 Kg4 c6 h5 b5 cxb5 cxb5 b3 Kc8 Kf3 bxa4 bxa4 Kd7 Kg4 Kc8 Kf5 Kb8 Ke4 Kb7 Kd4 Kc6 Kc3 Kb6 Kc4 Kc6 Kd4 Kb6 Kd5 Kb7 Kc5 Ka6 Kc6 Ka7 Kb5 Kb7 Kxa5 Kc6 Kb4 Kb6 a5+ Ka6 Ka4 Kb7 
 33	+0.23 	61.1M  	0:02.10	Nde6+ Kc8 c4 Kd7 Kg4 c6 h5 b5 cxb5 cxb5 b3 Kc8 Kf3 bxa4 bxa4 Kd7 Kg4 Kc8 Kf5 Kb8 Ke4 Kb7 Kd4 Kc6 Kc3 Kb6 Kc4 Kc6 Kd4 Kb6 Kd5 Kb7 Kc5 Ka6 Kc6 Ka7 Kb5 Kb7 Kxa5 Kc6 Kb4 Kb6 a5+ Ka6 
 32	  0.00 	48.4M  	0:01.69	Nde6+ Kc8 h5 c6 Kg4 b5 b3 Kb7 Kf5 Kb6 Ke4 Ka6 Kd3 Kb6 c4 bxa4 bxa4 Kb7 Kd4 Kb6 Kc3 Ka6 Kb3 Kb7 Kb2 Kb8 Kc2 Kc8 Kc3 Kb7 
 31	  0.00 	33.8M  	0:01.20	Nde6+ Kc8 h5 c6 Kg4 b5 axb5 cxb5 Kf3 a4 Ke4 Kb7 Kd5 Kb6 Kd4 Kc6 Ke4 b4 cxb4 Kb5 Nc7+ Kc6 Nce6 
 30	  0.00 	31.4M  	0:01.12	Nde6+ Kc8 h5 c6 Kg4 b5 axb5 cxb5 Kf3 Kd7 Ke4 Kc6 Kd3 Kb6 Ke4 b4 cxb4 Kb5 Nc7+ Kc6 Nce6 Kb5 
 29	  0.00 	29.8M  	0:01.06	Nde6+ Kc8 h5 c6 Kg4 Kb7 Kf3 Ka6 Nc7+ Ka7 Nce6 Kb7 Ke4 b5 axb5 cxb5 Kd4 Kc6 Ke4 a4 Kd4 Kb6 Kd5 b4 Kc4 bxc3 Kxc3 Kb5 Nc7+ Kc5 Nce6+ Kb5 
 28	  0.00 	26.6M  	0:00.95	Nde6+ Kc8 h5 c6 Kg4 b5 axb5 cxb5 Kf3 Kd7 Ke4 Kc6 Kd3 a4 Ke4 Kb7 Kd5 Ka6 Kc6 Ka5 Kc5 a3 bxa3 Ka6 c4 bxc4 Kxc4 Ka5 Kc3 Ka4 Kb2 Ka5 
 27	 -0.02 	24.3M  	0:00.87	Nde6+ Kc8 h5 c6 Kg4 Kd7 Kg3 Ke8 Kf3 Ke7 Kg4 c5 Kf3 Kd7 Ke4 Kc6 Nd8+ Kc7 Nde6+ Kd7 Kf5 Kc8 c4 Kd7 Ke4 Kc6 Kf5 
 26	 -0.30 	17.1M  	0:00.62	Nde6+ Kc8 h5 c6 Kg4 Kb8 Kf3 Kb7 Ke4 Ka6 Kd4 Ka7 Ke4 Kb7 Kd4 Kc8 Ke3 Kd7 Kf3 Ke7 Kg4 Ke8 Kf3 Kf7 Kg3 b5 axb5 cxb5 Kg4 a4 Kf5 
 25	 -0.38 	14.2M  	0:00.52	Nde6+ Kc8 h5 Kd7 Kg4 c6 Kf3 Ke7 Kg3 b5 axb5 cxb5 Kf3 Kd7 Kg4 Kc8 Kf5 Kb7 Ke4 Kc6 Kd4 a4 Ke4 b4 cxb4 Kb5 Nc7+ Kc4 e6 Qf6 Nfd5 Qh4+ Ke5 
 24	 -0.38 	13.6M  	0:00.50	Nde6+ Kc8 h5 Kd7 Kg4 c6 Kf3 Ke7 Kg3 b5 axb5 cxb5 Kf3 Kd7 Kg4 Kc8 Kf5 Kb7 Ke4 Kc6 Kd4 a4 Ke4 b4 cxb4 Kb5 
 23	 -0.59 	10.8M  	0:00.40	Nde6+ Kc8 h5 c6 Kg4 Kd7 Kf3 Ke8 Kg4 Ke7 Kg3 b5 axb5 cxb5 Kg4 Ke8 Kf3 Kd7 Ke4 Kc6 Kd4 Kb6 Kd5 a4 Kd4 Kc6 Ke4 b4 cxb4 Kb5 Nc7+ Kc4 e6 Qf6 
 22	 -0.74 	9.39M  	0:00.34	Nde6+ Kc8 h5 c6 Kg4 Kd7 Kf3 Ke7 Kg4 Ke8 Kf5 Kf7 Kg4 Ke7 Kf5 Ke8 Kg4 b5 axb5 cxb5 Kf5 Kd7 Ke4 Kc6 Nd4+ Kc5 Nb3+ Kb6 Nd4 Qg7 Nd5+ Kb7 e6 Qg2+ Ke5 Qh2+ Ke4 Qh1+ Ke5 Qxh5+ Kd6 
 21	 -0.74 	9.15M  	0:00.34	Nde6+ Kc8 h5 c6 Kg4 Kd7 Kf3 Ke7 Kg4 Ke8 Kf5 Kf7 Kg4 Ke7 Kf5 Ke8 Kg4 b5 axb5 cxb5 Kf5 Kd7 Ke4 Kc6 Nd4+ Kc5 Nb3+ Kb6 Nd4 
 20	 -0.91 	7.91M  	0:00.29	h5 Kd7 Nde6 c6 Kg4 b5 axb5 cxb5 Kf5 Kc6 Ke4 a4 Nd4+ Kc5 e6 Qg7 Nf5 Qb7+ Ke5 Qb8+ Ke4 Qe8 Ke5 Kc6 Nd4+ Kb6 Nd5+ Kc5 e7 Kc4 Nf5 Qxh5 Nf6 
 19	 -0.93 	5.27M  	0:00.20	Nde6+ Kc8 Kg4 c6 h5 b5 axb5 cxb5 Kf5 Kd7 Ke4 Kc6 Nd4+ Kc5 Nb3+ Kb6 Nd4 a4 Nde6 Ka5 Nc7 Qc6+ Ncd5 b4 cxb4+ Kb5 e6 Qc2+ Ke5 Qxb2+ Kd6 Qc1 Nc7+ Kc4 
 18	 -1.08 	2.32M  	0:00.08	Nde6+ Kc8 h5 c6 Kg4 b5 axb5 cxb5 Kf3 Kd7 Ke4 Kc6 Nd4+ Kc5 Nb3+ Kb6 Nd4 Qg5 Nd5+ Kb7 e6 Qxh5 e7 Qe8 Nf5 Qg6 Ke5 Kc6 Nf6 
 17	 -1.13 	2.20M  	0:00.08	Nde6+ Kc8 h5 c6 Kg4 b5 axb5 cxb5 Kf5 Kb7 Ke4 a4 Nd4 Kb6 e6 Qg7 Nf5 Qf8 Ke5 Qb8+ Ke4 Kc6 Nd4+ Kc5 Nf5 Qa8+ Ke5 Qh8+ Ke4 Qf6 Nd3+ Kc6 Nf4 
 16	 -1.28 	1.59M  	0:00.06	Nde6+ Kd7 Kg4 c6 h5 b5 axb5 cxb5 Kf3 Kc6 Ke3 a4 Ke4 b4 Nd4+ Kc5 e6 Qf8 cxb4+ Kc4 Nf5 Kxb4 Ke5 Kb3 
 15	 -0.89 	885945	0:00.03	Nde6+ Kc8 h5 c6 Kg4 b5 axb5 cxb5 Kf3 Kb7 Ke4 a4 Kd5 Ka6 Kc6 Ka5 Kc5 a3 bxa3 Ka4 
 14	 -0.86 	802296	0:00.03	Nde6+ Kc8 h5 Kb7 Kg4 c6 Kf3 Ka6 Nc7+ Ka7 Nce6 b5 axb5 cxb5 Ke4 a4 Kd5 Kb6 Kd4 
 13	 -0.96 	454486	0:00.02	Nde6+ Kd7 Kg4 Kc6 h5 Kb7 Kf5 Kb8 Ke4 c6 Kd4 Kc8 Ke4 c5 Kf5 
 12	 -1.05 	258817	0:00.01	Nde6+ Kc8 h5 Kb7 Kg4 Ka7 Kf5 c6 Ke4 Kb7 Kf5 b5 axb5 cxb5 Ke4 b4 cxb4 axb4 
 11	 -1.21 	152943	0:00.01	h5 c6 Nde6+ Kc8 Kg4 Kd7 Kf5 b5 axb5 cxb5 Ke4 
 10	 -1.51 	88716  	0:00.00	Nde6+ Kc8 h5 c6 Kg4 Kd7 Kf5 b5 axb5 cxb5 
  9	 -1.63 	59245  	0:00.00	Nde6+ Kc8 h5 c6 Kg4 Kd7 Kf5 b5 axb5 cxb5 Nd4 b4 cxb4 
  8	 -1.61 	49289  	0:00.00	h5 Kc8 Nde6 c6 Kg4 Kd7 Kf5 b5 
  7	 -1.60 	43181  	0:00.00	h5 Kc8 Nde6 c6 
  6	 -1.95 	22778  	0:00.00	Nde6+ Ke7 Kg4 c5 Nc7 Qc6 
  5	 -2.08 	13105  	0:00.00	Kg4 Qg7+ Kf5 Qg3 h5 Qf2 
  4	 -2.00 	9393    	0:00.00	Kg4 Qg7+ Kf5 Kd7 e6+ Ke7 
  3	 -1.57 	5840    	0:00.00	Kg4 Kd7 e6+ Ke8 
  2	 -2.14 	3004    	0:00.00	Kg4 Kd7 e6+ Ke7 
  1	 -1.88 	651      	0:00.00	Kg4 
  1	Found 1511 tablebases
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peter
Posts: 3185
Joined: Sat Feb 16, 2008 7:38 am
Full name: Peter Martan

Re: Neghina position

Post by peter »

Hi Ernest!
ernest wrote: ↑Mon Nov 25, 2019 3:33 am I wonder what today's situation is for this 10-year old Neghina position (prison for Queen)
Sting is able to get the winning move with a line of progress (even if output shows now and then also failures in their endings like the last of the copied lines below) and +- eval rather quickly:

3k4/2pq3p/pp5R/4P3/P6P/2PN4/1PN3K1/8 w - - 0 1

Analysis by Sting 18 (based on Stockfish 2.1.1) 64bit:

Code: Select all

1.Kf3 Qxd3+ 
  =  (-0.08 --)   Depth: 7   00:00:04  14kN
...
1.Kf3 Qxd3+ 
  -/+  (-1.01 --)   Depth: 12   00:00:05  384kN
1.Nd4 
  -/+  (-0.76 ++)   Depth: 12   00:00:05  515kN
...
1.Nd4 Qg7+ 2.Kh3 Qxh6 3.Nf4 Kd7 4.Nde6 Qxe6+ 5.Nxe6 Kxe6 6.Kg4 Kxe5 7.Kg5 Ke4 8.Kh6 Kf5 9.Kxh7 Kg4 10.Kg6 Kxh4 11.Kf5 Kg3 12.Ke5 b5 13.axb5 axb5 14.Kd5 Kf3 
  +/=  (0.36)   Depth: 21   00:00:06  4075kN
...
1.Nd4 Qg7+ 2.Kh3 Qxh6 3.Nf4 Kd7 4.Nde6 Qxe6+ 5.Nxe6 Kxe6 6.Kg4 Kxe5 7.Kg5 Ke4 8.Kh6 Kf5 9.Kxh7 Kg4 10.Kg6 Kxh4 11.Kf5 c6 12.Ke5 Kg3 13.Kd6 b5 14.Kxc6 bxa4 15.Kd5 Kf3 16.c4 
  +/-  (1.13)   Depth: 25   00:00:08  34171kN
...
1.Nd4 Qg7+ 2.Kh3 Qxh6 3.Nf4 Kd7 4.Nde6 Qxe6+ 5.Nxe6 Kxe6 6.Kg4 Kxe5 7.Kg5 Ke4 8.Kh6 Kf5 9.Kxh7 Kg4 10.Kg6 Kxh4 11.Kf5 c6 12.Ke5 b5 13.Kd6 bxa4 14.Kxc6 a5 15.Kd5 a3 16.bxa3 Kg5 17.c4 
  +-  (1.85)   Depth: 26   00:00:13  98223kN
...
1.Nd4 Qg7+ 2.Kh3 Qxh6 3.Nf4 c6 4.h5 Kd7 5.Nde6 Ke7 6.Kh4 Kd7 7.Kg3 Ke7 8.Kf3 Kf7 9.Ke3 Ke7 10.Ke4 Kf7 11.Kf5 Ke7 12.b4 Ke8 13.Ke4 Kf7 14.Kd4 Ke7 15.a5 bxa5 16.bxa5 Qxe6 17.Nxe6 Kxe6 18.Ke4 h6 19.c4 Ke7 20.Kf5 Kf7 21.c5 Ke7 
  +-  (2.02)   Depth: 31   00:00:39  470MN
...
1.Nd4 Qg7+ 2.Kh3 Qxh6 3.Nf4 Kd7 4.Nde6 Kc6 5.h5 b5 6.a5 b4 7.c4 Kd7 8.Kg4 b3 9.Kg3 Ke7 10.Kf3 Kd7 11.Ke4 Ke7 12.Kd5 Kd7 13.Kc5 Qxe6 14.Nxe6 Kxe6 15.Kd4 Ke7 16.Kd5 Kf7 17.h6 Ke7 18.c5 Kd7 19.c6+ 
  +-  (2.30)   Depth: 33   00:02:24  2020MN
...
1.Nd4 Qg7+ 2.Kh3 Qxh6 3.Nf4 Kd7 4.Nde6 Ke7 5.Kg3 c6 6.h5 a5 7.b4 axb4 8.cxb4 c5 9.bxc5 bxc5 10.a5 Kd7 11.Kf3 c4 12.Ke4 c3 13.Kd3 Kc6 14.Kxc3 Kb5 15.Kd4 Kxa5 16.Kc5 Ka4 17.Kc4 Ka5 18.Kd4 Kb5 19.Kd5 Kb4 20.Kc6 Kc4 21.Kd6 Kb4 22.Ke7 Kc3 23.Kd8 Kc4 24.Kd7 Kb4 25.Kd6 
  +-  (3.95)   Depth: 34   00:06:37  6077MN
BTW LC0 at 2xRTX 2080Ti with net 49921 failed at a single trial of 5 minutes, sticking to 1.Kf3?

Maybe longer runs would change that, but I don't think so, because I gave LC0 a try with some Forward- Backward, that doesn't work here neither compared to good A-B-engines.

Needs well about 10 moves going into winning line to see the evals climb and no more then backwarding about five moves to keep a positive eval. With further Backward it's getting negative soon and at starting position Kf3? arises again.
Peter.
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Jouni
Posts: 3279
Joined: Wed Mar 08, 2006 8:15 pm

Re: Neghina position

Post by Jouni »

Definitely too difficult for SF: after executing 20 plies of main line evaluation is still long time 0,00! You need something stronger

Analysis by Houdini 6 x64-pext Tac:
...
1.Kf3 Qxd3+ 2.Ne3 Qb1 3.e6 Qxb2 4.Nf5 Qxc3+ 5.Kf4 b5 6.Rxh7 Qc4+ 7.Ke5 Qc3+ 8.Kf4
= (0.00) Depth: 34/73 00:04:08 2547mN, tb=1274065
1.Kf3 Qxd3+ 2.Ne3 Qb1 3.e6 Qxb2 4.Nf5 Qxc3+ 5.Kf4 b5 6.Rxh7 Qc4+ 7.Ke5 Qc3+ 8.Kf4
= (0.00 --) Depth: 34/73 00:05:43 3518mN, tb=1882262
1.Nd4
= (0.14 ++) Depth: 34/73 00:06:49 4196mN, tb=2279769
1.Nd4
= (0.24 ++) Depth: 34/73 00:07:30 4615mN, tb=2387440
1.Nd4
+/= (0.39 ++) Depth: 34/73 00:07:54 4871mN, tb=2460395
1.Nd4
+/= (0.60 ++) Depth: 34/73 00:09:30 5851mN, tb=2732264
1.Nd4
+/- (0.87 ++) Depth: 34/73 00:10:25 6405mN, tb=2859194
1.Nd4
+/- (1.23 ++) Depth: 34/73 00:12:32 7703mN, tb=3266129
1.Nd4
+- (1.70 ++) Depth: 34/73 00:14:26 8862mN, tb=3677185
1.Nd4
+- (2.31 ++) Depth: 34/73 00:18:48 11490mN, tb=4619189
1.Nd4 Qg7+ 2.Kh3 Qxh6 3.Nf4 Ke8 4.Nde6 Kd7 5.h5 Qxh5+ 6.Nxh5 Kxe6 7.Kg4 Kxe5 8.Kf3 Kd5 9.b3 Ke5 10.Ke3 Kf5 11.c4 a5 12.Kd4 Ke6 13.Ng3 Kd6 14.Ne4+ Kc6 15.Nf6 h6 16.Nh5 Kd6 17.Ng3 Ke6 18.c5 Kd7 19.Kd5 c6+ 20.Kd4 bxc5+ 21.Kxc5 Kc7 22.Nh5 Kb7 23.Kd6 Kb6 24.Ng3 Kb7 25.Kd7
+- (2.18) Depth: 34/73 00:19:57 12200mN, tb=5038873
Jouni
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Jouni
Posts: 3279
Joined: Wed Mar 08, 2006 8:15 pm

Re: Neghina position

Post by Jouni »

Addition: also very difficult to Crystal. Nobody is perfect :) .
Jouni
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Spliffjiffer
Posts: 416
Joined: Thu Aug 02, 2012 7:48 pm
Location: Germany

Re: Neghina position

Post by Spliffjiffer »

Jouni wrote: ↑Mon Nov 25, 2019 1:27 pm Definitely too difficult for SF: after executing 20 plies of main line evaluation is still long time 0,00! You need something stronger

Analysis by Houdini 6 x64-pext Tac:
...
1.Kf3 Qxd3+ 2.Ne3 Qb1 3.e6 Qxb2 4.Nf5 Qxc3+ 5.Kf4 b5 6.Rxh7 Qc4+ 7.Ke5 Qc3+ 8.Kf4
= (0.00) Depth: 34/73 00:04:08 2547mN, tb=1274065
1.Kf3 Qxd3+ 2.Ne3 Qb1 3.e6 Qxb2 4.Nf5 Qxc3+ 5.Kf4 b5 6.Rxh7 Qc4+ 7.Ke5 Qc3+ 8.Kf4
= (0.00 --) Depth: 34/73 00:05:43 3518mN, tb=1882262
1.Nd4
= (0.14 ++) Depth: 34/73 00:06:49 4196mN, tb=2279769
1.Nd4
= (0.24 ++) Depth: 34/73 00:07:30 4615mN, tb=2387440
1.Nd4
+/= (0.39 ++) Depth: 34/73 00:07:54 4871mN, tb=2460395
1.Nd4
+/= (0.60 ++) Depth: 34/73 00:09:30 5851mN, tb=2732264
1.Nd4
+/- (0.87 ++) Depth: 34/73 00:10:25 6405mN, tb=2859194
1.Nd4
+/- (1.23 ++) Depth: 34/73 00:12:32 7703mN, tb=3266129
1.Nd4
+- (1.70 ++) Depth: 34/73 00:14:26 8862mN, tb=3677185
1.Nd4
+- (2.31 ++) Depth: 34/73 00:18:48 11490mN, tb=4619189
1.Nd4 Qg7+ 2.Kh3 Qxh6 3.Nf4 Ke8 4.Nde6 Kd7 5.h5 Qxh5+ 6.Nxh5 Kxe6 7.Kg4 Kxe5 8.Kf3 Kd5 9.b3 Ke5 10.Ke3 Kf5 11.c4 a5 12.Kd4 Ke6 13.Ng3 Kd6 14.Ne4+ Kc6 15.Nf6 h6 16.Nh5 Kd6 17.Ng3 Ke6 18.c5 Kd7 19.Kd5 c6+ 20.Kd4 bxc5+ 21.Kxc5 Kc7 22.Nh5 Kb7 23.Kd6 Kb6 24.Ng3 Kb7 25.Kd7
+- (2.18) Depth: 34/73 00:19:57 12200mN, tb=5038873
as we SF users all know it is very hard to change its "mind" for SF when it has sth found already that it is comfortable with...so i tried a 10 min search with Bluefish from the root-position with multiPV=1 and had to abbort without success (as expected)...
but if i play 1.Nd4 Qg7+ (cleared hash) Bluefish gets it quite quickly:

no tablebases, 1024 MB hash, engine = Bluefish 191121 (i think but not sure) 64 bit popcnt on an old 7870k-APU 4 cores (all credits to Eelco and the SF-team):

Code: Select all

FEN: 3k4/2p3qp/pp5R/4P3/P2N3P/2PN3K/1P6/8 b - - 3 2

Bluefish191121:
 1/1	00:00	 129	65k	-2,87	1.Kg2-f3 Dg7xh6
 2/2	00:00	 180	90k	-2,87	1.Kg2-f3 Dg7xh6
 3/3	00:00	 487	244k	-3,47	1.Kg2-f1 Dg7xh6 2.b2-b4
 4/4	00:00	 10k	2.572k	-3,26	1.Kg2-f3 Dg7xh6 2.b2-b4
 5/6	00:00	 10k	2.612k	-3,26	1.Kg2-f3 Dg7xh6 2.b2-b4 Dh6-h5+ 3.Kf3-e3 Kd8-d7
 6/8	00:00	 11k	2.675k	-3,48	1.Kg2-f3 Dg7xh6 2.b2-b4 Dh6-h5+ 3.Kf3-e3 Kd8-d7 4.e5-e6+ Kd7-e7
 7/11	00:00	 11k	2.831k	-3,11	1.Kg2-f3 Dg7xh6 2.b2-b4 Dh6xh4 3.b4-b5
 8/13	00:00	 27k	3.353k	-3,75	1.Kg2-f3 Dg7xh6 2.b2-b4 Dh6xh4 3.a4-a5 Dh4-h1+ 4.Kf3-e3 Dh1-h3+ 5.Ke3-d2 Dh3-g2+ 6.Kd2-e3 Kd8-d7 7.a5xb6
 9/17	00:00	 41k	3.411k	-3,98	1.Kg2-f3 Dg7xh6 2.b2-b4 Dh6xh4 3.a4-a5 Dh4-h3+ 4.Kf3-e4 b6xa5 5.b4xa5 h7-h5 6.Sd3-f4 Dh3xc3
 10/19	00:00	 116k	3.851k	-2,82	1.Kg2-h3 Dg7xh6 2.Sd3-f4 a6-a5 3.Sf4-d5 Kd8-c8
 11/13	00:00	 127k	3.851k	-2,50	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-e8 3.Kh3-g4 Dh6-g7+ 4.Kg4-f5 a6-a5 5.b2-b3 Ke8-d7 6.e5-e6+ Kd7-d6
 12/20	00:00	 150k	3.835k	-1,92	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-e8 3.Sd4-e6 Ke8-d7 4.Kh3-g4 a6-a5 5.h4-h5 c7-c5 6.Kg4-f3
 13/19	00:00	 199k	3.978k	-1,51	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-c8 3.Sd4-e6 c7-c5 4.Kh3-g3 b6-b5 5.a4xb5 a6xb5 6.Kg3-g4 Kc8-b7 7.Se6xc5+ Kb7-b6 8.Sc5-e4 Dh6-g7+ 9.Kg4-f5 Dg7-f7+ 10.Kf5-g5
 14/22	00:00	 245k	4.017k	-1,55	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-c8 3.Sd4-e6 c7-c6 4.Kh3-g4 Kc8-d7 5.Kg4-g3 a6-a5 6.Kg3-g4 b6-b5 7.a4xb5 c6xb5 8.h4-h5 Kd7-e7 9.Se6-d4 Dh6-g7+ 10.Kg4-f3
 15/31	00:00	 344k	4.092k	-1,40	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-c8 3.Sd4-e6 c7-c6 4.Kh3-g4 Kc8-b7 5.h4-h5 a6-a5 6.Kg4-f3 b6-b5 7.a4xb5 c6xb5 8.Kf3-e4 Kb7-b6 9.Se6-d4
 16/26	00:00	 478k	4.124k	-1,31	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-c8 3.Sd4-e6 c7-c6 4.Kh3-g4 a6-a5 5.h4-h5 Kc8-b7 6.Kg4-f3 b6-b5 7.a4xb5 c6xb5 8.Kf3-e4 a5-a4 9.Se6-d4 Kb7-b6 10.e5-e6 Dh6-g7 11.Sf4-d5+ Kb6-c5
 17/33	00:00	 662k	4.444k	-1,07	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.Kh3-g4 a6-a5 5.h4-h5 Kc8-b7 6.Kg4-f3 b6-b5 7.a4xb5 c6xb5 8.Kf3-e4 a5-a4 9.Ke4-d4 Kb7-b6 10.Sf4-d5+ Kb6-c6
 18/31	00:00	 769k	4.552k	-1,06	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.Kh3-g4 Kc8-b7 5.h4-h5 Kb7-c8 6.Kg4-f5 Kc8-d7 7.Kf5-g4 Kd7-e7 8.Kg4-g3 a6-a5 9.Kg3-f3 Ke7-d7 10.Kf3-g3 b6-b5
 19/34	00:00	 1.223k	4.931k	-0,87	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.Kh3-g4 a6-a5 5.h4-h5 b6-b5 6.a4xb5 c6xb5 7.Kg4-f3 Kc8-b7 8.Kf3-e3 Kb7-a6 9.Ke3-e4 b5-b4 10.c3xb4 a5xb4 11.Ke4-d5 Ka6-b5 12.b2-b3
 20/33	00:00	 1.359k	4.941k	-0,86	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.Kh3-g4 a6-a5 5.h4-h5 b6-b5 6.a4xb5 c6xb5 7.Kg4-f5 Kc8-b7 8.Kf5-e4 a5-a4 9.Ke4-d4 Kb7-b6 10.Sf4-d5+ Kb6-a5 11.Se6-f4 Dh6-g7 12.Kd4-e4 b5-b4 13.Sd5xb4 Dg7-b7+ 14.Sf4-d5
 21/29	00:00	 1.737k	5.154k	-0,79	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-c8 3.Sd4-e6 Kc8-b7 4.Kh3-g4 Kb7-a7 5.h4-h5 Ka7-b7 6.Kg4-g3 Kb7-b8 7.Kg3-f3 a6-a5 8.Kf3-e4 Kb8-c8 9.Ke4-d4 c7-c6 10.Kd4-e4 b6-b5 11.a4xb5 c6xb5 12.Ke4-d4 Kc8-b7 13.Kd4-d5 a5-a4 14.Kd5-c5 Kb7-a6
 22/34	00:00	 1.997k	5.229k	-0,79	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-c8 3.Sd4-e6 Kc8-b7 4.Kh3-g4 a6-a5 5.h4-h5 c7-c6 6.Kg4-f5 Kb7-a6 7.Se6-c7+ Ka6-a7 8.Sc7-e6 b6-b5 9.a4xb5 c6xb5 10.Kf5-e4 Ka7-b6 11.Sf4-d5+ Kb6-b7 12.Sd5-f4 Kb7-c6 13.Ke4-d4 Kc6-b6 14.Kd4-e4 a5-a4
 23/36	00:00	 2.355k	5.340k	-0,77	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-d7 3.Sd4-e6 Kd7-c6 4.h4-h5 a6-a5 5.Kh3-g4 Kc6-b7 6.Kg4-f5 Kb7-b8 7.Kf5-e4 Kb8-c8 8.Ke4-d5 Kc8-d7 9.Kd5-e4 c7-c6 10.Ke4-d4 Kd7-e8 11.Kd4-d3 b6-b5 12.a4xb5 c6xb5 13.Kd3-e4 Ke8-e7 14.Ke4-f5 Ke7-d7 15.Kf5-e4 Kd7-e8 16.Ke4-f5 Ke8-e7 17.Kf5-e4
 24/45	00:00	 3.346k	5.576k	-0,66	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-c8 3.Sd4-e6 c7-c6 4.Kh3-g3 a6-a5 5.h4-h5 b6-b5 6.a4xb5 c6xb5 7.Kg3-f3 Kc8-b7 8.Kf3-e4 Kb7-c6 9.Ke4-d4 a5-a4 10.Se6-d8+ Kc6-b6 11.Sd8-e6 Kb6-a6 12.Se6-c7+ Ka6-a7 13.Sc7-e6 Ka7-b6 14.Sf4-d5+ Kb6-a5 15.Se6-f4 b5-b4 16.c3xb4+ Ka5-b5 17.e5-e6 Dh6-g7+ 18.Kd4-e4 Dg7xb2
 25/45	00:00	 5.571k	5.821k	-0,77	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-d7 4.h4-h5 a6-a5 5.Kh3-g3 b6-b5 6.a4xb5 c6xb5 7.Kg3-f3 a5-a4 8.Kf3-e4 Kd7-c6 9.Ke4-d3 Kc6-b7 10.Kd3-e4 Kb7-b6 11.Sf4-d5+ Kb6-c6 12.Sd5-f4 b5-b4 13.c3xb4 Kc6-b5 14.Se6-c7+ Kb5-c4 15.e5-e6 Dh6-g7 16.Sc7-d5 Dg7-d4+ 17.Ke4-f5 Dd4xb2 18.e6-e7 Db2-b1+ 19.Kf5-f6 Db1-e4 20.Kf6-f7
 26/42	00:01	 7.474k	5.994k	-0,33	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 a6-a5 5.Kh3-g4 b6-b5 6.a4xb5 c6xb5 7.Kg4-f5 Kc8-b7 8.Kf5-e4 Kb7-c6 9.Ke4-d4 a5-a4 10.Kd4-d3 Kc6-b7 11.Kd3-e4 Kb7-b6 12.Sf4-d5+ Kb6-c6 13.Sd5-f4 Kc6-d7 14.Ke4-e3 Kd7-e7
 27/30	00:01	 9.185k	6.119k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 a6-a5 8.Kg4-f3 Kb8-b7 9.Kf3-e4 Kb7-c8 10.Ke4-f3 Kc8-b8 11.Kf3-e4 Kb8-b7 12.Ke4-f3
 28/26	00:01	 9.884k	6.151k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 a6-a5 8.Kg4-f3 Kb8-b7 9.Kf3-e4 Kb7-c8 10.Ke4-f3
 29/24	00:01	 11.062k	6.190k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 a6-a5 8.Kg4-f3 Kb8-c8 9.Kf3-g4 Kc8-b7 10.Kg4-f3
 30/39	00:01	 11.628k	6.225k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 a6-a5 8.Kg4-f3 Kb8-a7 9.Kf3-e4 Ka7-a6 10.Se6-c7+ Ka6-b7 11.Sc7-e6 Kb7-c8 12.Ke4-f3 Kc8-b8 13.Kf3-e4 Kb8-b7
 31/26	00:02	 13.244k	6.262k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 a6-a5 8.Kg4-f3 Kb8-a7 9.Kf3-e4 Ka7-a6 10.Se6-c7+ Ka6-b7 11.Sc7-e6 Kb7-c8 12.Ke4-f3 Kc8-b8 13.Kf3-e4
 32/35	00:02	 15.085k	6.270k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a7
 33/15	00:02	 16.009k	6.275k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a7
 34/40	00:02	 17.949k	6.320k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3 Ka8-a7 9.Kf3-e4 Ka7-b8 10.Ke4-f3 Kb8-c8 11.Kf3-g3 Kc8-b7 12.Kg3-g4 Kb7-a7
 35/22	00:03	 19.300k	6.370k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3 Ka8-a7 9.Kf3-e4 Ka7-b8 10.Ke4-f3
 36/22	00:03	 21.272k	6.402k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3 Ka8-a7 9.Kf3-e4 Ka7-b8 10.Ke4-f3
 37/41	00:04	 26.096k	6.432k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3 Ka8-a7 9.Kf3-e4 Ka7-b8 10.Ke4-f3 Kb8-c8 11.Kf3-g4 Kc8-b8
 38/22	00:05	 35.167k	6.352k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3
 39/20	00:07	 44.761k	6.156k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3
 40/20	00:08	 53.593k	6.201k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3 Ka8-a7 9.Kf3-e4 Ka7-b7 10.Ke4-f3
 41/20	00:08	 54.593k	6.192k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3
 42/20	00:10	 64.253k	6.239k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3
 43/20	00:10	 68.403k	6.241k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3
 44/50	00:12	 80.175k	6.255k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3 Ka8-a7 9.Kf3-e4 Ka7-b7 10.Ke4-f3 Kb7-b8
 45/22	00:15	 98.825k	6.179k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3
 46/20	00:17	 109.657k	6.170k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b8 7.Kf3-g4 Kb8-a8 8.Kg4-f3
 47/57	00:27	 166.836k	6.171k	 0,00	1.Kg2-h3 Dg7xh6 2.Sd3-f4 c7-c6 3.Sd4-e6+ Kd8-c8 4.h4-h5 Kc8-b7 5.Kh3-g3 Kb7-a7 6.Kg3-f3 Ka7-b7
48/58+	01:28	 558.586k	6.303k	+0,12	1.Kg2-h3
 48/58+	01:30	 572.873k	6.313k	+0,24	1.Kg2-h3
 48/65+	02:11	 871.700k	6.650k	+3,91	1.Kg2-h3
 48/65	02:17	 922.532k	6.711k	+3,92	1.Kg2-h3 Dg7xh6 2.Sd3-f4 Kd8-e8 3.Sd4-e6 Ke8-d7 4.h4-h5 Dh6xh5+ 5.Sf4xh5 Kd7xe6 6.Kh3-g4 Ke6xe5 7.Kg4-f3 Ke5-d5 8.b2-b3 Kd5-e5 9.Sh5-f4 a6-a5 10.Kf3-e3 Ke5-d6 11.Ke3-e4 Kd6-c6 12.Ke4-e5 Kc6-c5 13.Sf4-d5 Kc5-c6 14.Sd5-f6 h7-h6 15.Ke5-e6 b6-b5 16.a4xb5+ Kc6xb5 17.Ke6-d5 Kb5-a6 18.Kd5-c5 a5-a4 19.b3xa4 Ka6-a5 20.Kc5-c6 Ka5xa4 21.c3-c4 Ka4-b3 22.c4-c5 Kb3-c4 23.Sf6-d7 h6-h5 24.Kc6xc7 h5-h4 25.Kc7-d6
 49/56+	02:29	 1.006.393k	6.734k	+4,08	1.Kg2-h3
 49/56+	02:34	 1.037.059k	6.731k	+4,24	1.Kg2-h3
 49/61	05:26	 2.129.954k	6.530k	+6,42	1.Kg2-h3
for all the "non compilers" and 64bit OS users with popcnt-support, its here (note that the .dll files u need to have in the same directory as the .exe):
https://drive.google.com/file/d/1k-Ta-Y ... sp=sharing
Wahrheiten sind Illusionen von denen wir aber vergessen haben dass sie welche sind.
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ernest
Posts: 2041
Joined: Wed Mar 08, 2006 8:30 pm

Re: Neghina position

Post by ernest »

I am a bit suspicious (disappointed?) that in your solution, at depth 48,
see 4.h4-h5 Dh6xh5+
the Black Queen is surrendering so early, in order for White to win...
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Spliffjiffer
Posts: 416
Joined: Thu Aug 02, 2012 7:48 pm
Location: Germany

Re: Neghina position

Post by Spliffjiffer »

:-)...ok its very often the case that the PV is NOT accurate, wether in SF nor its derivatives nor in any engine ??...the intersting point is that the EV changes from 0.00 to +...thats where you (we) get intersested in ;-)
Last edited by Spliffjiffer on Tue Nov 26, 2019 4:55 am, edited 1 time in total.
Wahrheiten sind Illusionen von denen wir aber vergessen haben dass sie welche sind.
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Ovyron
Posts: 4556
Joined: Tue Jul 03, 2007 4:30 am

Re: Neghina position

Post by Ovyron »

Spliffjiffer wrote: ↑Tue Nov 26, 2019 4:45 am :-)...ok its very often the case that the PV is NOT accurate, weather in SF nor its derivatives nor in any engine ??
Yes, and people take advantage of it to win correspondence chess games.
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Dann Corbit
Posts: 12537
Joined: Wed Mar 08, 2006 8:57 pm
Location: Redmond, WA USA

Re: Neghina position

Post by Dann Corbit »

Ovyron wrote: ↑Tue Nov 26, 2019 4:48 am
Spliffjiffer wrote: ↑Tue Nov 26, 2019 4:45 am :-)...ok its very often the case that the PV is NOT accurate, weather in SF nor its derivatives nor in any engine ??
Yes, and people take advantage of it to win correspondence chess games.
A pv is only accurate to the point where the opponent engine or player makes a different move.
So you get 1 ply, and maybe more.

It is especially laughable since the tail of the pv sometimes gets decorated with qsearch nodes.
"Ooh! Look! A checkmate is coming!"
Taking ideas is not a vice, it is a virtue. We have another word for this. It is called learning.
But sharing ideas is an even greater virtue. We have another word for this. It is called teaching.
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