Which engines allow Black knight sac for three pawns here?

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Graham Banks
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Which engines allow Black knight sac for three pawns here?

Post by Graham Banks » Fri Jan 24, 2014 4:21 am

[d]r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R W

Two very strong engines have recently played Bd3 here, allowing black to play Nxf4.
After Bxf4, dxc4; Ne2, dxe5; the resulting big pawn phalanx has then given black a big advantage.
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tpetzke
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Re: Which engines allow Black knight sac for three pawns her

Post by tpetzke » Fri Jan 24, 2014 6:35 am

Hi Graham,

is this the right position. I don't see how an engine (especially a strong one) can play Bd3 here. It will lose due to sending an illegal move.

Thomas...
Thomas...

=======
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Codesquid
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Re: Which engines allow Black knight sac for three pawns her

Post by Codesquid » Fri Jan 24, 2014 7:26 am

Assuming you mean Be3, Octochess occasionally wants to play it, though exd or dxc eventually replace it if searching deep enough:

Code: Select all

 20	0.00	350.0M	0:41.27	d4xc5    d6xe5    f4xe5   Nd7xe5   Qd1-e2   Ne5xf3   Qe2xf3      O-O      O-O   Qd8-a5    g2-g4   Bg7xc3    b2xc3   Nh5-f6   Bc1-h6   Rf8-d8    g4-g5   Qa5xc5   Kg1-h1   Nf6-h5   
 19	+0.18	248.7M	0:30.43	d4xc5    d6xe5    f4xe5   Nd7xe5   Qd1-e2   Ne5xf3   Qe2xf3      O-O      O-O   Qd8-a5    g2-g4   Bg7xc3    b2xc3   Nh5-f6   Bc1-h6   Rf8-d8    g4-g5   Qa5xc5   Kg1-h1   
 19	-0.04	167.9M	0:21.44	e5xd6      O-O      O-O    e7xd6   Bc1-e3   Rf8-e8   Qd1-d2   Nd7-b6    b2-b3    f7-f5   Ra1-e1    c5-c4   Kg1-h1    c4xb3    c2xb3   Ra8-c8    a2-a4   Qd8-d7   Nc3-b5   
 19	-0.16	137.5M	0:18.20	Bc1-e3   Nh5xf4   Be3xf4    c5xd4   Nc3-e2    d6xe5   Bf4-g3   Qd8-b6    c2-c3   Ra8-d8    c3xd4    e5xd4   Bg3-f2   Nd7-c5      O-O    e7-e5   Ra1-c1      O-O   Kg1-h1   
 18	+0.14	75.8M	0:11.32	Bc1-e3   Nh5xf4   Be3xf4    c5xd4   Nc3-e2    d6xe5   Bf4-g3    f7-f5   Qd1-d2    f5-f4   Bg3-h4    h7-h6    O-O-O    g6-g5   Bh4-f2      O-O   Qd2-d3   Qd8-b6   
 17	+0.06	34.6M	0:06.38	Bc1-e3   Nh5xf4   Be3xf4    c5xd4   Nc3-e2    d6xe5   Bf4-g3    f7-f5   Qd1-d2   Ra8-c8    O-O-O      O-O   Qd2-b4    f5-f4   Bg3-h4   Nd7-c5   Qb4-c4   
 16	+0.02	19.1M	0:04.40	Bc1-e3   Nh5xf4   Be3xf4    c5xd4   Nc3-e2    d6xe5   Bf4-g3    f7-f5   Qd1-d2   Ra8-c8    O-O-O      O-O   Kc1-b1    f5-f4   Bg3-h4   Nd7-c5   
 15	+0.20	11.8M	0:03.41	Bc1-e3   Nh5xf4   Be3xf4    c5xd4   Nc3-e2    d6xe5   Bf4-g3   Qd8-a5    c2-c3    d4xc3    b2xc3    O-O-O      O-O   Nd7-c5   Qd1-c2   
 14	+0.29	8.7M	0:02.87	Bc1-e3   Nh5xf4   Be3xf4    c5xd4   Nc3-e2    d6xe5   Bf4-g3   Qd8-a5    c2-c3    d4xc3    b2xc3    O-O-O      O-O   Nd7-c5   
 14	-0.03	6.6M	0:02.42	e5xd6      O-O      O-O    e7xd6   Bc1-e3   Rf8-e8   Qd1-d2   Nd7-b6   Qd2-d3    c5-c4   Qd3-d2   Nh5-f6    d4-d5   Nf6-g4   
 13	+0.12	3.8M	0:01.73	e5xd6      O-O      O-O    e7xd6   Rf1-e1   Nd7-b6    g2-g4   Bg7xd4   Nf3xd4    c5xd4   Nc3-b5   Nh5-f6   Nb5xd4   
 12	+0.14	2.7M	0:01.40	e5xd6      O-O      O-O    e7xd6   Rf1-e1   Rf8-e8   Re1xe8   Qd8xe8   Nc3-b5   Qe8-e7    d4xc5    d6xc5   
 11	+0.14	1.8M	0:01.01	e5xd6      O-O      O-O    e7xd6   Rf1-e1    f7-f5   Bc1-e3   Qd8-b6    b2-b3   Rf8-e8   Nc3-d5   
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Graham Banks
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Re: Which engines allow Black knight sac for three pawns her

Post by Graham Banks » Fri Jan 24, 2014 7:52 am

tpetzke wrote:Hi Graham,

is this the right position. I don't see how an engine (especially a strong one) can play Bd3 here. It will lose due to sending an illegal move.

Thomas...
Yes - I meant Be3. :oops:
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velmarin
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Re: Which engines allow Black knight sac for three pawns her

Post by velmarin » Fri Jan 24, 2014 8:43 am

There e6.
Analysis by Bouquet 1.8b x64:
1. = (0.00): 1.Ae3 Cxf4 2.Axf4 cxd4 3.e6 fxe6 4.Cxd4 Axd4 5.Dxd4 e5 6.Axe5 Cxe5 7.0-0-0 Da5 8.Cd5 Dxa2 9.Cc7+ Rf7 10.Cxa8 Txa8 11.Thf1+ Rg7 12.Tf3 Da1+ 13.Rd2 Da5+ 14.Rc1 Da1+
2. = (-0.11): 1.dxc5 dxe5 2.fxe5 Cxe5 3.De2 Cxf3+ 4.Dxf3 Da5 5.Ad2 Dxc5 6.0-0-0 Dc6 7.Dxc6+ bxc6 8.The1 Td8 9.Te4 Td4 10.Ae3 Txd1+ 11.Cxd1 f5 12.Ta4 Rf7 13.Txa7 Td8

[D]r2qk2r/pp1nppbp/3pP1p1/8/3p1B2/2N2N2/PPP3PP/R2QK2R b KQkq - 0 3

zullil
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Re: Which engines allow Black knight sac for three pawns her

Post by zullil » Fri Jan 24, 2014 10:24 am

Graham Banks wrote:[d]r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R W
The position field might be OK, but the FEN above is invalid. (When I copied it into Stockfish, the engine analyzed the position as if Black were to move!)

This seems better: r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R w KQkq -

Stockfish goes for exd6:

Code: Select all

info depth 30 seldepth 42 score cp 0 nodes 907095890 nps 7552146 time 120111 multipv 1 pv e5d6 e8g8 e1g1 e7d6 a2a4 h5f6 f4f5 d8b6 a4a5 b6c6 f5g6 f7g6 f1e1 a8e8 d4d5 c6a6 e1e6 f6g4 c3e4 d7f6 e4c3 f6h5 c3e4 h5f6

Vinvin
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Re: Which engines allow Black knight sac for three pawns her

Post by Vinvin » Fri Jan 24, 2014 10:29 am

zullil wrote:
Graham Banks wrote:2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R W
The position field might be OK, but the FEN above is invalid. (When I copied it into Stockfish, the engine analyzed the position as if Black were to move!)

This seems better: r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R w KQkq -

Stockfish goes for exd6:

Code: Select all

info depth 30 seldepth 42 score cp 0 nodes 907095890 nps 7552146 time 120111 multipv 1 pv e5d6 e8g8 e1g1 e7d6 a2a4 h5f6 f4f5 d8b6 a4a5 b6c6 f5g6 f7g6 f1e1 a8e8 d4d5 c6a6 e1e6 f6g4 c3e4 d7f6 e4c3 f6h5 c3e4 h5f6
It's black to play :wink:
r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R w KQkq - 0 1
Last edited by Vinvin on Fri Jan 24, 2014 10:32 am, edited 2 times in total.

zullil
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Re: Which engines allow Black knight sac for three pawns her

Post by zullil » Fri Jan 24, 2014 10:30 am

Vinvin wrote:
zullil wrote:
Graham Banks wrote:2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R W
The position field might be OK, but the FEN above is invalid. (When I copied it into Stockfish, the engine analyzed the position as if Black were to move!)

This seems better: r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R w KQkq -

Stockfish goes for exd6:

Code: Select all

info depth 30 seldepth 42 score cp 0 nodes 907095890 nps 7552146 time 120111 multipv 1 pv e5d6 e8g8 e1g1 e7d6 a2a4 h5f6 f4f5 d8b6 a4a5 b6c6 f5g6 f7g6 f1e1 a8e8 d4d5 c6a6 e1e6 f6g4 c3e4 d7f6 e4c3 f6h5 c3e4 h5f6
It's black to play :wink:
No, it isn't. :wink: :wink:

Vinvin
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Re: Which engines allow Black knight sac for three pawns her

Post by Vinvin » Fri Jan 24, 2014 10:32 am

zullil wrote:
Vinvin wrote:
zullil wrote:
Graham Banks wrote:2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R W
The position field might be OK, but the FEN above is invalid. (When I copied it into Stockfish, the engine analyzed the position as if Black were to move!)

This seems better: r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R w KQkq -

Stockfish goes for exd6:

Code: Select all

info depth 30 seldepth 42 score cp 0 nodes 907095890 nps 7552146 time 120111 multipv 1 pv e5d6 e8g8 e1g1 e7d6 a2a4 h5f6 f4f5 d8b6 a4a5 b6c6 f5g6 f7g6 f1e1 a8e8 d4d5 c6a6 e1e6 f6g4 c3e4 d7f6 e4c3 f6h5 c3e4 h5f6
It's black to play :wink:
No, it isn't. :wink: :wink:
Oops, I forgot 1..Be3
[D]r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N1BN2/PPP3PP/R2QK2R b KQkq - 1 1

Vinvin
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Re: Which engines allow Black knight sac for three pawns her

Post by Vinvin » Fri Jan 24, 2014 10:46 am

Graham Banks wrote:r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R W

Two very strong engines have recently played Bd3 here, allowing black to play Nxf4.
After Bxf4, dxc4; Ne2, dxe5; the resulting big pawn phalanx has then given black a big advantage.
Stockfish analyze with 5 best moves after 10 min (Intel 3.1 Ghz, 2 cores) agrees 1.Be3 is the best move and 1...Nxf4 is the best reply.

[D] r2qk2r/pp1nppbp/3p2p1/2p1P2n/3P1P2/2N2N2/PPP3PP/R1BQK2R w KQkq - 0 1

Code: Select all

Stockfish_14011911_32bit:
...
 27/43	09:27	 909.472.555	1.601.807	-0,25	dxc5 dxe5 fxe5 Cxe5 De2 Cxf3+ Dxf3 Dd4 Fd2 0-0 0-0-0 Dxc5 g4 Cf6 g5 Cd7 Fe3 Dc7 Cd5 De5 c3 Tae8 h4 e6 Cb4 Db5 Fxa7 Ce5 De3 Cc4 Dd3
 27/43	09:27	 909.472.555	1.601.807	-0,35	Ce2 cxd4 exd6 e5 0-0 0-0 fxe5 Cxe5 Cexd4 Dxd6 c3 Tfe8 Db3 Cxf3+ Cxf3 Cf6 Cd4 Dd5 Fd2 Dxb3 Cxb3 Te2 Tae1 Tae8
 27/43	09:27	 909.472.555	1.601.807	-0,07	exd6 0-0 0-0 exd6 Rh1 Chf6 f5 Db6 Tb1 Tfe8 Ff4 Tad8 fxg6 hxg6 Dd2 cxd4 Cxd4 Ce4 Cxe4 Txe4 c3 Da6 Cf3 Fe5 Cxe5
 27/43	09:27	 909.472.555	1.601.807	-0,04	e6 fxe6 Cg5 Da5 Cxe6 cxd4 Cxg7+ Cxg7 Dxd4 0-0 Fd2 Ce6 Dd5 Dxd5 Cxd5 Cf6 Cxf6+ Txf6 g3 Cd4 0-0 Te6 c3 Te2 Tad1 Ce6 Tf2 Txf2 Rxf2 Rf7 Fe3 b6 Rf3 Tc8 Te1
 27/43	09:27	 909.472.555	1.601.807	 0,00	Fe3 Cxf4 Fxf4 cxd4 e6 fxe6 Cxd4 Fxd4 Dxd4 e5 Fxe5 Cxe5 0-0-0 0-0 Dd5+ Rg7 Dxb7 Te8 The1 Db8 Dxb8 Taxb8 Cd5 Tb7 Cf4 Tbb8 Cd5
Last edited by Vinvin on Fri Jan 24, 2014 10:50 am, edited 3 times in total.

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