Rybka 3mp - Nxe4

[Al G. L.]

[d] r2qrbk1/1b3pp1/p4n1p/1p6/1PppP1N1/P2P1Q2/B4PPP/R1BR2K1 b - - 0 1

is Nxe4 the best?
are there any other engines that would play such an unclear sacrifice?

[royb]

[d] r2qrbk1/1b3pp1/p4n1p/1p6/1PppP1N1/P2P1Q2/B4PPP/R1BR2K1 b - - 0 1

is Nxe4 the best?
are there any other engines that would play such an unclear sacrifice?

Glaurung 2.2 does (analysis on my ancient 1.67 GHz single core system):

2 -0.49 1.... Nxg4 2.Qxg4 cxd3 (0.32)
3 -0.09 1.... Nxg4 2.Qxg4 Qf6 3.Qd7 (0.33)
3 -0.33 1.... cxd3 2.Bxh6 Bxe4 (0.33)
4 -0.01 1.... cxd3 2.Nxf6+ Qxf6 3.Qxf6 gxf6 4.f3 f5 5.Rxd3 fxe4 6.Rxd4 exf3 (0.34)
4 -0.07 1.... Nxg4 2.Qxg4 cxd3 3.Qg6 Qf6 (0.34)
5 -0.27 1.... Nxg4 2.Qxg4 Qc8 3.Qh5 Qd7 4.Bf4 cxd3 (0.35)
6 -0.27 1.... Nxg4 2.Qxg4 Qc8 3.Qh5 Qd7 4.Bf4 cxd3 (0.36)
7 -0.58 1.... Nxg4 2.Qxg4 Qf6 3.dxc4 d3 4.Bd2 Rxe4 5.Qd7 (0.42)
8 -0.58 1.... Nxg4 2.Qxg4 Qf6 3.Bf4 g5 4.Bc7 cxd3 5.e5 Qc6 (0.51)
9 -0.27 1.... Nxg4 2.Qxg4 Qf6 3.Bf4 g5 4.Bg3 cxd3 5.f3 Bc8 6.Qh5 (0.63)
10 -0.43 1.... Nxg4 2.Qxg4 Qf6 3.Bf4 c3 4.Rdc1 Bd6 5.Bxd6 Qxd6 6.Bb3 Qf6 7.Qd7 (1.00)
11 -0.39 1.... Nxg4 2.Qxg4 Qf6 3.Bf4 c3 4.Rdc1 Bd6 5.Bxd6 Qxd6 6.Qf5 Re7 7.Bb3 Rae8 (1.56)
12 -0.50 1.... Nxg4 2.Qxg4 Qf6 3.Bf4 c3 4.e5 Qc6 5.e6 Rxe6 6.Bxe6 Qxe6 7.Qxe6 fxe6 8.Rac1 Kf7 (2.96)
13 -0.29 1.... Nxg4 2.Qxg4 Qf6 3.Bf4 Rad8 4.e5 Qc6 5.Rdc1 g5 6.h4 Qxg2+ 7.Qxg2 Bxg2 8.hxg5 hxg5 9.Bxg5 (7.88)
13 -0.66 1.... Nxe4 2.dxe4 Rxe4 3.Qh3 Bc8 4.f3 Bxg4 5.fxg4 d3 6.Be3 Qd7 7.Qf3 Rae8 8.Re1 Qxg4 (12.80)
14 -0.72 1.... Nxe4 2.dxe4 Rxe4 3.Qf5 Qc8 4.Qxc8 Bxc8 5.h3 d3 6.Bd2 Bxg4 7.hxg4 Rxg4 8.f3 Rh4 9.Kf2 Bd6 (18.69)
15 -0.72 1.... Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kh8 5.Re1 Rxe1+ 6.Qxe1 d3 7.Rb1 Qe8 8.Be3 f5 9.Nf2 Qg6 (30.08)
16 -1.15 1.... Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.Qh3 Bc8 5.f3 Bxg4 6.fxg4 d3 7.Be3 Qd7 8.Re1 Qxg4 9.Qxg4 Rxg4 10.Bd2 Rc8 (76.43)
17 -0.92 1.... Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kf8 5.Rb1 Qc7 6.Ne5 Re8 7.Rf1 Bxe5 8.fxe5 Re2 9.Rb2 Qxe5 10.Rxe2 Qxe2 (120.34)
18 -0.80 1.... Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kf8 5.Ne5 Bxe5 6.fxe5 d3 7.Be3 Qd5 8.Rd2 Qxe5 9.Qxe5 Rxe5 10.Bd4 Re7 11.Bc5 Be4 12.Bxe7+ Kxe7 (197.34)

It sees quite a bit of compensation for the sacrificed material.

Roy

[kgburcham]

[d] r2qrbk1/1b3pp1/p4n1p/1p6/1PppP1N1/P2P1Q2/B4PPP/R1BR2K1 b - -

9/32 0:01 -0.61 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (1.559.167) 1510
10/32 0:01 -0.74 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (1.993.217) 1518
11/32 0:01 -0.74 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (2.535.551) 1530
12/33 0:02 -0.63 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (4.457.056) 1593
13/45 0:07 -0.82 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 h5 5.Nh6+ Kf8 6.Nf5 Qf6 7.Qg5 Qxg5 8.fxg5 Be5 9.Bb1 (12.914.443) 1693
14/45 0:10 -0.82 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 h5 5.Nh6+ Kf8 6.Nf5 Qf6 7.Qg5 Qxg5 8.fxg5 Be5 9.Bb1 (18.057.252) 1737
15/49 0:47 -0.91 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kf8 5.Bb1 d3 6.Be3 Qc7 7.Bxd3 cxd3 8.Rac1 Rc4 9.Nf2 (85.047.466) 1778
16/51 1:33 -0.89 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kh8 5.Bb1 d3 6.Ra2 Qe7 7.Rf1 Bc7 8.Ne5 Qe6 9.Bb2 (172.464.774) 1841
17/53 6:11 -1.39 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.Nxh6+ Kf8 5.Qh3 gxh6 6.Bxh6+ Kg8 7.f4 Qf6 8.Bg5 Qe6 9.f5 Qe5 10.Kh1 a5 11.bxa5 (687.509.244) 1853

[royb]

[d] r2qrbk1/1b3pp1/p4n1p/1p6/1PppP1N1/P2P1Q2/B4PPP/R1BR2K1 b - -

9/32 0:01 -0.61 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (1.559.167) 1510
10/32 0:01 -0.74 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (1.993.217) 1518
11/32 0:01 -0.74 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (2.535.551) 1530
12/33 0:02 -0.63 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (4.457.056) 1593
13/45 0:07 -0.82 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 h5 5.Nh6+ Kf8 6.Nf5 Qf6 7.Qg5 Qxg5 8.fxg5 Be5 9.Bb1 (12.914.443) 1693
14/45 0:10 -0.82 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 h5 5.Nh6+ Kf8 6.Nf5 Qf6 7.Qg5 Qxg5 8.fxg5 Be5 9.Bb1 (18.057.252) 1737
15/49 0:47 -0.91 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kf8 5.Bb1 d3 6.Be3 Qc7 7.Bxd3 cxd3 8.Rac1 Rc4 9.Nf2 (85.047.466) 1778
16/51 1:33 -0.89 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kh8 5.Bb1 d3 6.Ra2 Qe7 7.Rf1 Bc7 8.Ne5 Qe6 9.Bb2 (172.464.774) 1841
17/53 6:11 -1.39 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.Nxh6+ Kf8 5.Qh3 gxh6 6.Bxh6+ Kg8 7.f4 Qf6 8.Bg5 Qe6 9.f5 Qe5 10.Kh1 a5 11.bxa5 (687.509.244) 1853

That was very quick for the engine above! What engine was used for this analysis?

Roy

[Dr.Wael Deeb]

[d] r2qrbk1/1b3pp1/p4n1p/1p6/1PppP1N1/P2P1Q2/B4PPP/R1BR2K1 b - -

9/32 0:01 -0.61 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (1.559.167) 1510
10/32 0:01 -0.74 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (1.993.217) 1518
11/32 0:01 -0.74 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (2.535.551) 1530
12/33 0:02 -0.63 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Rxd2 6.Bxd2 (4.457.056) 1593
13/45 0:07 -0.82 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 h5 5.Nh6+ Kf8 6.Nf5 Qf6 7.Qg5 Qxg5 8.fxg5 Be5 9.Bb1 (12.914.443) 1693
14/45 0:10 -0.82 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 h5 5.Nh6+ Kf8 6.Nf5 Qf6 7.Qg5 Qxg5 8.fxg5 Be5 9.Bb1 (18.057.252) 1737
15/49 0:47 -0.91 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kf8 5.Bb1 d3 6.Be3 Qc7 7.Bxd3 cxd3 8.Rac1 Rc4 9.Nf2 (85.047.466) 1778
16/51 1:33 -0.89 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Kh8 5.Bb1 d3 6.Ra2 Qe7 7.Rf1 Bc7 8.Ne5 Qe6 9.Bb2 (172.464.774) 1841
17/53 6:11 -1.39 1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.Nxh6+ Kf8 5.Qh3 gxh6 6.Bxh6+ Kg8 7.f4 Qf6 8.Bg5 Qe6 9.f5 Qe5 10.Kh1 a5 11.bxa5 (687.509.244) 1853

That was very quick for the engine above! What engine was used for this analysis?

Roy

I assume that Kgburcham used a modified version of Zappa Mexico II....

[acase]

I tried a few engines and here is what 3 of them came up with:

[d]r2qrbk1/1b3pp1/p4n1p/1p6/1PppP1N1/P2P1Q2/B4PPP/R1BR2K1 b - - 0 1

Analysis by Shredder 8 UCI:

1...Nxe4 2.dxc4 Nc3 3.Qxb7 Nxd1 4.Bxh6
-/+ (-1.27) Depth: 6/18 00:00:00 31kN
1...Nxe4 2.dxe4 Qd6 3.Bf4 Rxe4 4.Bxd6 Re1+ 5.Rxe1
-/+ (-1.02 --) Depth: 7/19 00:00:00 61kN
1...Nxe4 2.dxe4 Bxe4 3.Qf4 Rc8 4.Ne5 Qd5
-/+ (-0.99) Depth: 7/20 00:00:00 76kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.Nxh6+ Kf8 5.Nxf7 Kxf7
-/+ (-1.22) Depth: 8/19 00:00:00 209kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.Nxh6+ Kf8 5.Qh3 Rh4 6.Nxf7 Kxf7
-/+ (-1.27) Depth: 9/23 00:00:00 378kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re2 5.Rd2 Qh4 6.Qxh4 Rxg2+ 7.Rxg2
-/+ (-1.03) Depth: 10/31 00:00:01 637kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re6 5.Bb2 Re2 6.Rxd4 Rxg2+ 7.Qxg2 Bxg2 8.Kxg2
-/+ (-0.95) Depth: 11/33 00:00:01 1222kN
1...Nxe4 2.Bf4 Nd6 3.Qg3 Nf5 4.Nxh6+ Nxh6 5.Bxh6 Re6 6.Bg5 Qd5 7.dxc4 bxc4 8.Bxc4 Qxc4 9.Qd3 Qxd3
-/+ (-1.08) Depth: 12/36 00:00:05 4059kN
1...Nxe4 2.dxe4 Rxe4 3.Qh3 Bc8 4.f3 Bxg4 5.fxg4 Qd6 6.g5 Rae8 7.Bb2 hxg5
-/+ (-1.09) Depth: 13/38 00:00:07 5915kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re6 5.Re1 Rxe1+ 6.Qxe1 Bc7 7.Bd2 d3 8.Nf6+ gxf6 9.Qe8+ Qxe8
-/+ (-1.21) Depth: 14/36 00:00:13 11771kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re6 5.Bb2 Re2 6.Nxh6+ Kf8 7.Bxd4 Rxg2+ 8.Qxg2 gxh6 9.Qxb7 Qg5+ 10.fxg5 Bxh2+ 11.Kxh2
-/+ (-0.96 --) Depth: 15/35 00:00:19 16468kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re6 5.Bb2 h5 6.Ne5 Bxe5 7.Bxd4 Bxd4+ 8.Rxd4 Qxd4+ 9.Qf2 Qxa1+ 10.Qf1 Qxa2
-/+ (-0.96) Depth: 15/45 00:00:24 21359kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re6 5.Bb2 h5 6.Ne5 Bxe5 7.Bxd4 Bxd4+ 8.Rxd4 Qxd4+ 9.Kf1 Qxa1+ 10.Qe1 Rxe1+ 11.Kf2 Qxa2+ 12.Kxe1 Bxg2
-/+ (-1.21 !) Depth: 16/49 00:00:53 46434kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re6 5.Bb2 h5 6.Bxd4 hxg4 7.Bb1 Re2 8.Ra2 Rxa2 9.Bxa2 Qd7 10.Bb1 Re8 11.Be5
-/+ (-1.39) Depth: 16/51 00:01:08 61202kN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re6 5.Bb2 h5 6.Bxd4 hxg4 7.Bb1 Re2 8.Ra2 Rxa2 9.Bxa2 Qd7 10.Bb1 Rc8 11.Bc2 Qe6
-/+ (-1.27) Depth: 17/55 00:01:45 93285kN
1...Nxe4 2.dxe4 Rxe4 3.Qf5 Qe7 4.Bd2 Bc8 5.Qd5 Rxg4 6.Bxc4 bxc4 7.Qxc4 Bb7 8.Qxd4 Rxd4 9.Bc1
-+ (-1.51) Depth: 18/54 00:04:31 238mN
1...Nxe4 2.dxe4 Rxe4 3.Qg3 Bd6 4.f4 Re6 5.Bb2 h5 6.Ne5 Bxe5 7.fxe5 Rg6 8.Rxd4 Qb6 9.Qf2 Rxg2+ 10.Qxg2 Bxg2 11.Kxg2 Re8 12.Kg1
-+ (-1.70) Depth: 19/59 00:09:10 479mN


Analysis by Fritz 10:

1...Nxe4 2.dxc4 Re7 3.cxb5 Nc3 4.Nxh6+ gxh6 5.Qg4+ Kh8 6.bxa6 Ne2+
-+ (-1.59) Depth: 8/24 00:00:00 108kN
1...Nxe4 2.dxc4 Re7 3.cxb5 Nc3 4.Nxh6+ gxh6 5.Qg4+ Kh8 6.bxa6 Ne2+ 7.Kh1 Rxa6
-+ (-1.59) Depth: 9/26 00:00:00 275kN
1...Nxe4 2.dxc4 Re7 3.cxb5 Nc3 4.Nxh6+ gxh6 5.Qg4+ Kh8 6.bxa6 Ne2+ 7.Kh1 Rxa6
-+ (-1.59) Depth: 10/25 00:00:00 435kN
1...Nxe4
-+ (-1.87) Depth: 11/31 00:00:01 2014kN
1...Nxe4 2.dxc4
-+ (-1.59) Depth: 12/33 00:00:03 3279kN
1...Nxe4 2.dxc4 Re7
-+ (-1.59) Depth: 12/36 00:00:04 5465kN
1...Nxe4 2.dxc4 Re7 3.Bb2 Nc3 4.Nf6+ Kh8 5.Qf5 Ne2+ 6.Kh1
-+ (-1.75) Depth: 13/36 00:00:09 11608kN
1...Nxe4 2.dxc4
-+ (-1.46) Depth: 14/34 00:00:18 22293kN
1...Nxe4 2.dxc4 h5
-+ (-1.46) Depth: 14/44 00:00:25 31577kN
1...Nxe4 2.dxc4 Nc3 3.Qxb7 Nxd1 4.Bd2 Nc3 5.Bxc3 dxc3 6.cxb5 Qe7
-/+ (-1.35) Depth: 15/37 00:00:51 64233kN
1...Nxe4
-+ (-1.63) Depth: 16/39 00:01:42 128mN
1...Nxe4 2.dxc4 Nc3 3.Qxb7 Nxd1 4.Bd2 Nc3 5.Bxc3 dxc3 6.cxb5 Qe7 7.Qxe7 Rxe7 8.bxa6 Rxa6 9.Ne3 Re8 10.Bc4 Ra7 11.Nd5 Rc8 12.Bd3 c2
-+ (-1.61) Depth: 17/40 00:04:13 321mN
1...Nxe4 2.dxe4
-/+ (-1.33) Depth: 18/43 00:08:37 655mN
1...Nxe4 2.dxe4 Rxe4
-/+ (-1.33) Depth: 18/52 00:09:59 760mN

Fritz 11 seems to like Re6 better

Analysis by Fritz 11:

1...Re6 2.Bf4 Bd6 3.h3 Rc8 4.Re1 Bxf4 5.Qxf4 Nxg4 6.hxg4 a5
-/+ (-0.90) Depth: 9/29 00:00:00 253kN
1...Re6 2.Bf4 Bd6 3.h3 Rc8 4.Rac1 Nxg4 5.Qxg4 Rg6 6.Qf5 Bxf4
-/+ (-0.94) Depth: 10/26 00:00:00 449kN
1...Re6 2.Bf4 Rc8 3.Rac1 Bd6 4.Rd2 Bxf4 5.Qxf4 Nxg4 6.Qxg4 Re5 7.Rdc2 a5
-/+ (-0.85) Depth: 11/33 00:00:00 1043kN
1...Re6 2.Bf4 Rc8 3.Rac1 Bd6 4.Bxd6 Qxd6 5.dxc4 Nxg4 6.Qxg4 Rxe4 7.Qf5 Re2 8.cxb5
-/+ (-0.91) Depth: 12/34 00:00:01 1749kN
1...Re6 2.Bf4 Rc8 3.Rac1 Bd6 4.Bxd6 Qxd6 5.dxc4 Nxg4 6.Qxg4 Rxe4 7.Qf5 g6 8.c5 Qxh2+
=/+ (-0.69) Depth: 13/36 00:00:03 3829kN
1...Re6 2.Bf4 Rc8 3.Rac1 Bd6 4.Bxd6 Qxd6 5.dxc4 Nxg4 6.Qxg4 Rxe4 7.Qf5 Qc7 8.Bb1 g6 9.Qf6
-/+ (-0.79) Depth: 14/32 00:00:05 6755kN
1...Re6 2.Bf4 Qe7 3.h4 a5 4.Bd2 Nxg4 5.Qxg4 Rg6 6.Qf5 axb4 7.h5 Rf6 8.Bxb4 Rxf5 9.Bxe7 Rxh5
-/+ (-1.02) Depth: 15/34 00:00:20 25748kN
1...Re6 2.Bf4 Qe7 3.h4 a5 4.Bd2 Nxg4 5.Qxg4 Rg6 6.Qf5 axb4 7.h5 Rf6 8.Bxb4 Rxf5 9.Bxe7 Rxh5
-/+ (-1.02) Depth: 16/36 00:00:31 38713kN
1...Re6 2.Bf4 Qe7 3.Qh3 a5 4.Bd2 Nxg4 5.Qxg4 axb4 6.Bxb4 Qc7 7.Bxf8 Kxf8 8.dxc4 Rxe4 9.Qg3 Qd7 10.h3 Rc8 11.cxb5 Qxb5
-/+ (-1.04) Depth: 17/38 00:01:15 93856kN
1...Re6 2.Bf4 Qe7 3.Qh3 a5 4.Bd2 Nxg4 5.Qxg4 Rg6 6.Qf5 Rf6 7.Qxb5 c3 8.Bd5 Bxd5 9.Qxd5 Rd8 10.Qxa5 cxd2 11.b5 Rc8
-/+ (-1.04) Depth: 18/38 00:01:43 130mN
1...Re6 2.Bf4 Qe7 3.Qh3 a5 4.Bd2 Nxg4 5.Qxg4 Rg6 6.Qf5 Rf6 7.Qxb5 c3 8.Bd5 Bxd5 9.Qxd5 Rd8 10.Qxa5 cxd2 11.b5 Rc8
-/+ (-1.04) Depth: 19/38 00:02:51 217mN
1...Re6 2.Nxf6+ Rxf6 3.Qg4 Rg6 4.Qh5 Rc8 5.g3 Qf6 6.Bf4 Re8 7.Qf5 c3 8.Re1 Qxf5 9.exf5 Rxe1+
-/+ (-1.04) Depth: 20/43 00:09:02 697mN

[PauloSoare]

I assume that Kgburcham used a modified version of Zappa Mexico II....

How can this be possible Dr. Wael?

[Dr.Wael Deeb]

I assume that Kgburcham used a modified version of Zappa Mexico II....

How can this be possible Dr. Wael?

By tweaking the engines parameters in the UCI configuration window....