Test Position: Nxg2!!

[swami]

8
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1
	a	b	c	d	e	f	g	h

r1b2rk1/1pp2ppp/2n2q2/p1b1p3/2N1Pn2/1BP1BN1P/PPQ2PPK/R4R2 b - - 0 14

Solution: Nxg2

Evaluation: Significantly slight positive score and a good position for black. If your engine finds it, then it can play aggressive chess.

Explanation : In the end, Black gains 3 pawns and active position advantage, in compensation for Bishop.

[AdminX]

[d] r1b2rk1/1pp2ppp/2n2q2/p1b1p3/2N1Pn2/1BP1BN1P/PPQ2PPK/R4R2 b - - 0 14

Solution: Nxg2

Evaluation: Significantly slight positive score and a good position for black. If your engine finds it, then it can play aggressive chess.

Explanation : In the end, Black gains 3 pawns and active position advantage, in compensation for Bishop.

Deep Junior 10 looks at it, but hey I would expect nothing less from Junior!

PS: Deep Junior evals it as even (=).


Analysis by Deep Junior 10:

1...Ba7 2.Bxa7 Rxa7 3.Qd1 Be6
= (0.21) Depth: 6 00:00:00 17kN
1...Ba7 2.Bxa7 Rxa7 3.Qd1 Be6
= (0.21) Depth: 6 00:00:00 17kN
1...Ba7 2.Bxa7 Rxa7 3.Qd1 Be6
= (0.21) Depth: 6 00:00:00 17kN
1...b6 2.Bxc5 bxc5 3.Qd1 Be6
= (0.18) Depth: 6 00:00:00 27kN
1...b6 2.Bxc5 bxc5 3.h4 Rd8 4.Rad1
= (0.09) Depth: 9 00:00:00 154kN
1...Nxg2 2.Kxg2 Bxh3+ 3.Kxh3 Qxf3+ 4.Kh2 Bxe3 5.Nxe3 Qh5+ 6.Kg1 Qg5+ 7.Kh2 Qh4+ 8.Kg1 Rfd8
= (-0.03) Depth: 9 00:00:00 226kN
1...Nxg2 2.Kxg2 Bxh3+ 3.Kxh3 Qxf3+ 4.Kh2 Qh5+ 5.Kg1 Qg4+ 6.Kh2
= (0.00) Depth: 12 00:00:00 1849kN
1...Nxg2 2.Kxg2 Bxh3+ 3.Kxh3 Qxf3+ 4.Kh2 Qh5+ 5.Kg1 Qg4+ 6.Kh2
= (0.00) Depth: 15 00:00:04 13700kN
1...Nxg2 2.Kxg2 Bxh3+ 3.Kxh3 Qxf3+ 4.Kh2 Qh5+ 5.Kg1 Qg4+ 6.Kh2
= (0.00) Depth: 17 00:00:36 117mN
1...Nxg2 2.Kxg2 Bxh3+ 3.Kxh3 Qxf3+ 4.Kh2 Qh5+ 5.Kg3 Qg6+ 6.Kf3 Qh5+
= (0.00) Depth: 18 00:02:22 429mN
1...Nxg2 2.Kxg2 Bxh3+ 3.Kxh3 Qxf3+ 4.Kh2 Qh5+ 5.Kg3 Qg6+ 6.Kf3 Qh5+
= (0.00) Depth: 19 00:03:55 697mN

8
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	a	b	c	d	e	f	g	h

r4rk1/1pp2ppp/2n5/p1b1p2q/2N1P3/1BP1BK2/PPQ2P2/R4R2 w - - 0 7

[kgburcham]

8
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6
5
4
3
2
1
	a	b	c	d	e	f	g	h

r1b2rk1/1pp2ppp/2n2q2/p1b1p3/2N1Pn2/1BP1BN1P/PPQ2PPK/R4R2 b - - 14

Rybka 2.3.2m x64
Hash 2048

10.00 0:01 -0.15 14...Be7 15.Ba4 Be6 16.b3 Nxh3 17.Bxc6 bxc6 18.Nfxe5 Bd6 (480.264) 378
10.00 0:02 -0.20 14...Qh6 15.Ba4 Bxe3 16.fxe3 Nxh3 17.gxh3 Bxh3 18.Kg3 Bxf1 19.Rxf1 Qg6+ 20.Kf2 Qe6 (998.441) 375
11.00 0:04 -0.20 14...Qh6 15.Ba4 Bxe3 16.fxe3 Nxh3 17.gxh3 Bxh3 18.Kg3 Bxf1 19.Rxf1 Qe6 20.Qb3 Qg6+ 21.Kf2 (1.424.131) 357
12.01 0:06 -0.25 14...Qh6 15.Ba4 Bxe3 16.fxe3 Nxh3 17.gxh3 Bxh3 18.Kg3 Bxf1 19.Rxf1 Qg6+ 20.Kf2 Qe6 21.Bxc6 (2.037.641) 340
13.01 0:09 -0.21 14...Qh6 15.Ba4 Bxe3 16.fxe3 Nxh3 17.gxh3 Bxh3 18.Kg3 Bxf1 19.Rxf1 Qg6+ 20.Kf2 Qe6 21.Bxc6 (3.121.450) 335
14.01 0:11 -0.21 14...Qh6 15.Ba4 Bxe3 16.fxe3 Nxh3 17.gxh3 Bxh3 18.Kg3 Bxf1 19.Rxf1 Qg6+ 20.Kf2 Qe6 21.Bxc6 (3.784.857) 339
15.01 0:24 -0.30 14...Qh6 15.Ba4 Bxe3 16.fxe3 Nxh3 17.gxh3 Bxh3 18.Kg3 Bxf1 19.Rxf1 Qe6 20.Qe2 Qg6+ 21.Kf2 (8.528.303) 356
16.01 1:24 -0.22 14...Qh6 15.Ng1 Ba7 16.Bxa7 Nxa7 17.Ne3 Nb5 18.Rfe1 Nd6 19.Ne2 Qh4 20.Nxf4 exf4 21.Nf5 (26.441.543) 321
17.01 1:43 -0.14 14...Qh6 15.Ng1 Ba7 16.Bxa7 Nxa7 17.Ne3 Nb5 18.Rfe1 Nd6 19.Ne2 Qh4 20.Nxf4 exf4 21.Nd5 (32.171.380) 319
17.02 2:23 -0.28 14...Be7 15.Ba4 Be6 16.b3 Nxh3 17.Rfd1 Bxc4 18.bxc4 Nf4 19.Rab1 Rab8 20.Rb5 Bd6 21.c5 (49.014.531) 349
18.01 3:17 -0.29 14...Be7 15.Ba4 Be6 16.b3 Nxh3 17.Rfd1 Bxc4 18.bxc4 Nf4 19.Rab1 Rab8 20.Rb5 Rfc8 21.g3 (71.179.499) 368
19.01 6:25 -0.23 14...Be7 15.Rfd1 Rb8 16.Ncd2 Rd8 17.Kh1 h6 18.Bxf4 Qxf4 19.Bd5 Bd6 20.Qd3 Ne7 21.Bb3 (131.640.712) 349
20.01 10:57 -0.20 14...Be7 15.Rfd1 Rb8 16.Ncd2 Rd8 17.Kh1 Bd6 18.a4 h6 19.Bd5 Bd7 20.Qb3 Ne7 21.Bc4 (219.352.001) 341
21.01 29:24 -0.19 14...Be7 15.Rfd1 Rb8 16.Ncd2 Rd8 17.Ne1 Bd7 18.Bxf4 Qxf4+ 19.Kg1 Qg5 20.Bd5 Bd6 21.Nef3 (610.108.427) 354
22.01 79:33 -0.26 14...Be7 15.Rfd1 b5 16.Ncd2 a4 17.Bd5 Ra6 18.Kg1 Qg6 19.Bxf4 exf4 20.Kh1 Rd8 21.c4 (1.567.406.029) 336
22.07 120:37 -0.78 14...Nxg2 15.Kxg2 Bxh3+ 16.Kxh3 Qxf3+ 17.Kh2 Ra6 18.Qd1 Qxe4 19.Qh5 Bxe3 20.fxe3 Nd8 21.Qf3 (2.469.663.451) 349
23.01 151:31 -0.89 14...Nxg2 15.Kxg2 Bxh3+ 16.Kxh3 Qxf3+ 17.Kh2 Ra6 18.Qd1 Qxe4 19.Qh5 Bxe3 20.fxe3 Nd8 21.Rg1 (3.141.137.306) 353
24.01 183:17 -0.96 14...Nxg2 15.Kxg2 Bxh3+ 16.Kg3 Bxf1 17.Rxf1 b5 18.Ncd2 Qg6+ 19.Kh3 Bxe3 20.fxe3 a4 21.Bd5 (3.821.679.506) 355
best move: Nf4xg2 time: 376:15.188 min n/s: 339.554 nodes: 7.485.692.313

[Marc MP]

[d] r1b2rk1/1pp2ppp/2n2q2/p1b1p3/2N1Pn2/1BP1BN1P/PPQ2PPK/R4R2 b - - 0 14

Solution: Nxg2

Evaluation: Significantly slight positive score and a good position for black. If your engine finds it, then it can play aggressive chess.

Explanation : In the end, Black gains 3 pawns and active position advantage, in compensation for Bishop.

Thanks for pointing out the position Swami.

For those interested the position is from the game Psakhis-Chekhov, 48th USSR Chess Championship, 1980-81.
Despite this spectacular defeat, Psakhis managed to finished first in the tournament(tied with Beliavsky).

You can replay the game online here (pgn also available on the page): http://www.chessgames.com/perl/chessgame?gid=1114656

Critical for the combination, is to play ...Ra6! here:

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	a	b	c	d	e	f	g	h

r4rk1/1pp2ppp/2n5/p1b1p3/2N1P3/1BP1Bq2/PPQ2P1K/R4R2 b - - 1 1

Here is the output from a few engines:

Code: Select all

Chess Tiger Gambit 2007.1
...
00:00:36.2	-0,14	16	22146848	Qh5+ Kg3 Bxe3 Nxe3 Qg5+...
00:00:44.2	1,00	16	26857388	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3   ...
00:00:46.9	1,08	16	28505767	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:00:52.1	0,52	17	31195245	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:01:21.6	0,34	18	49828616	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:03:37.1	0,96	19	130644112	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:05:57.5	1,06	20	205015716	Ra6 Qd1 Qxe4 Rg1 Qh4+ Kg2 ... 
00:11:15.9	1,16	21	379267711	Ra6 Qd1 Qxe4 Rg1 Qh4+ Kg2 ...
00:20:08.3	0,94	22	679999376	Ra6 Qd1 Qxe4 Rg1 Qh4+ Kg2 ... 
01:14:39.0	0,90	23	2526451642	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 Nd8 Rg1 a4 Bd1 Qxc4 Be2 Qe4 Bxa6 bxa6 Rxg7+ Kxg7 Rg1+ Kf6 Qg5+ Ke6 Rg4 

Bright 0.3a
...
00:02:09.5	0,00	15	83636263	Qh5+ Kg3 Qg6+ Kh2 Qh5+ 
00:07:13.7	0,00	16	254811159	Qh5+ Kg3 Qg6+ Kh2 Qh5+ 
00:18:46.4	0,00	17	615913964	Qh5+ Kg3 Qg6+ Kh2 Qh5+ 

Glaurung 2.1 (JA)
...
00:01:57.7	0,00	16	44000268	Qh5+ Kg2 Qg4+ Kh2 Qh5+ 
00:05:00.7	0,00	17	114784094	Qh5+ Kg3 Qg6+ Kh2 Qh5+ 
00:08:29.8	1,15	17	194128100	Ra6 Qd1 Qxe4 Re1 Nd4 cxd4 ... 
00:10:35.7	1,29	18	242285758	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:14:21.7	1,29	19	328931728	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:23:19.4	1,29	20	540333616	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:41:56.0	1,29	21	994006757	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 Nd8 Rg1 a4 Bd1 Qxc4 Be2 Qc6 Bxa6 Qxa6 Qxe5 Qh6+ Kg2 Ne6 Rad1 a3 bxa3 Qh4 Kf1 Qc4+ Ke1 Qxa2 

Fruit 2.3.1
...
00:07:50.0	0,00	17	249007449	Qh5+ Kg3 Qg6+ Kh3 Qh5+ ...
00:15:56.5	0,02	17	495257555	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:23:01.4	0,13	18	705810992	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 Nd8 Rg1 a4 Bd1 Qxc4 Be2 Rh6 Rxg7+ Kxg7 Rg1+ Kh8 Qxh6 Qxe2+ Rg2 Qxg2+ Kxg2 Rg8+ Kf3 Nc6 Qf6+ Rg7 Ke2 Kg8 

Toga 1.4 beta5c
...
00:01:05.0	0,00	16	36157856	Qh5+ Kg3 Qg6+ Kh3 Qh5+ ...
00:02:44.6	0,30	16	87480869	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:04:06.6	0,44	17	127291493	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:09:51.3	0,69	18	295579193	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 ...
00:20:03.6	0,81	19	597214580	Ra6 Qd1 Qxe4 Qh5 Bxe3 fxe3 Nd8 Rg1 a4 Bd1 f5 Rg3 Kh8 Nd2 Qd5 Qe2 a3 bxa3 Rh6+ Rh3 

[Terry McCracken]

[d] r1b2rk1/1pp2ppp/2n2q2/p1b1p3/2N1Pn2/1BP1BN1P/PPQ2PPK/R4R2 b - - 0 14

Solution: Nxg2

Evaluation: Significantly slight positive score and a good position for black. If your engine finds it, then it can play aggressive chess.

Explanation : In the end, Black gains 3 pawns and active position advantage, in compensation for Bishop.

Very Clever! I don't think chess programs will see this combination? As Marc said, 17..Ra6! must be seen before you sac the Night.

[swami]

Thanks Marc, and Terry, I have yet to see the Ra6 move, Hopefully those who have quads will post the analysis lines when they happen to come across this problem.

[kgburcham]

8
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	a	b	c	d	e	f	g	h

r1b2rk1/1pp2ppp/2n2q2/p1b1p3/2N1Pn2/1BP1BN1P/PPQ2PPK/R4R2 b - - 14

Deep Hiarcs Paderborn 2007:
Quad
Hash 2048

14...Be7
=/+ (-0.28) Depth: 14/36 00:00:28 38723kN
14...Be7 15.Ncd2 Rd8 16.Rad1 Bg4 17.Bxf4 Qxf4+ 18.Kg1 Bd7 19.Bd5 Rab8 20.a4
=/+ (-0.44) Depth: 16/40 00:02:18 190mN
14...Be7 15.Ncd2 Rd8 16.Rad1 Bg4 17.Bd5 a4
=/+ (-0.48) Depth: 17/42 00:04:38 382mN
14...Be7 15.Ncd2 Rd8 16.Rad1 Rb8 17.Ng1 b6 18.g3 Ne6 19.Bc4 b5 20.Bd5
=/+ (-0.45) Depth: 18/44 00:09:47 809mN
14...Be7 15.Ncd2 Rd8 16.Rad1 Rb8 17.a4 Bg4 18.Bxf4 Qxf4+ 19.Kg1 Bh5 20.Bd5 Bc5 21.Qb3 Ne7
=/+ (-0.45) Depth: 19/47 00:19:24 1624mN
14...Be7 15.Ncd2 Qh6 16.Ng1 Qg6 17.Bxf4
=/+ (-0.29) Depth: 20/53 00:50:07 4247mN
14...Qh6 15.Ng1 Qg6 16.g3 Ne6 17.Ba4
=/+ (-0.30) Depth: 20/53 01:19:49 6758mN
14...Nxg2
=/+ (-0.30) Depth: 20/54 01:25:39 7298mN
14...Nxg2 15.Kxg2 Bxh3+ 16.Kxh3 Qxf3+ 17.Kh2 Ra6 18.Qd1 Qxe4 19.Rg1 Qh4+ 20.Kg2 Nd4 21.cxd4 exd4
=/+ (-0.69) Depth: 20/55 01:43:51 9013mN
14...Nxg2
-/+ (-0.94) Depth: 21/56 02:15:28 11743mN
14...Nxg2 15.Kxg2 Bxh3+ 16.Kxh3 Qxf3+ 17.Kh2 Ra6 18.Qd1 Qxe4 19.Qh5 Bxe3 20.fxe3 Nd8 21.Qf3 Rh6+ 22.Kg2 Qg6+ 23.Kf2 a4 24.Nxe5 Qg5 25.Ng4 Rg6 26.Bxa4 h5 27.Qg3 hxg4
-/+ (-1.24) Depth: 21/59 02:53:26 15272mN
14...Nxg2 15.Kxg2 Bxh3+ 16.Kxh3 Qxf3+ 17.Kh2 Ra6 18.Qd1 Qxe4 19.Qh5 Bxe3 20.fxe3 Nd8 21.Qf3 Rh6+ 22.Kg2 Qg6+ 23.Kf2 a4 24.Nxe5 Qg5 25.Ng4 Rg6 26.Bd1 h5
-/+ (-1.31) Depth: 22/61 05:15:28 28642mN

Lev Psakhis (2535) - Valery A Chekhov (2415) [C55]
Vilnius URS ch Vilnius URS ch (10), 1980
1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.d3 Be7 5.Bb3 0–0 6.0–0 d5 7.Nbd2 dxe4 8.dxe4 Bc5 9.c3 a5 10.h3 Qe7 11.Qc2 Nh5 12.Nc4 Qf6 13.Kh2 Nf4 14.Be3 Nxg2 15.Kxg2 Bxh3+ 16.Kxh3 Qxf3+ 17.Kh2 Ra6 18.Qd1 Qxe4 19.Rg1 Qh4+ 20.Kg2 Nd4 21.cxd4 exd4 22.Bg5 Qxg5+ 23.Kf1 Qf5 24.Bc2 Qh3+ 25.Rg2 Rf6 26.Qd3 Rf3 27.Qxh7+ Qxh7 28.Bxh7+ Kxh7 29.Re1 0–1

[swami]

Finally! Hiarcs solved this! Are there any engines out there that can see Ra6 when choosing Nxg2?!

[Ignacio]

Hiarcs 12 needs 4:49 on my Quad, hash=512
FEN: r1b2rk1/1pp2ppp/2n2q2/p1b1p3/2N1Pn2/1BP1BN1P/PPQ2PPK/R4R2 w - - 0 1

Hiarcs12MPUCI:
12/31 00:03 3.786.372 1.250.394 +0,36 Qf6h6 Nf3g1 Bc5xe3 Nc4xe3 Bc8d7 Ra1d1 Ra8d8 Ng1e2 Nf4xg2 Ne3xg2
12/31 00:03 3.933.736 1.250.394 +0,37 Nf4xg2
12/36 00:04 5.475.645 1.329.362 +0,37 Nf4xg2 Kh2xg2
13/38- 00:07 9.527.784 1.416.711 +0,12 Nf4xg2 Kh2xg2
13/40 00:10 14.572.987 1.494.002 0,00 Nf4xg2 Kh2xg2 Bc8xh3+ Kg2xh3 Qf6xf3+ Kh3h2 Qf3h5+ Kh2g3 Qh5g6+ Kg3h2 Qg6h5+
13/40 00:10 15.560.006 1.483.115 0,00 Qf6h6
13/40 00:12 18.352.750 1.453.491 +0,41 Qf6h6 Nf3g1 Qh6g6 g2g3 Nf4e6 Ra1e1 Bc5xe3 Nc4xe3 Bc8d7 Ng1f3 Qg6h5 g3g4 Qh5h6 Bb3xe6 Bd7xe6 Kh2g2 Ra8d8 Ne3f5
14/40 00:20 27.868.129 1.414.941 +0,39 Qf6h6 Nf3g1 Qh6g6 g2g3 Nf4e6 f2f4 e5xf4
15/40 00:36 49.498.815 1.368.121 +0,40 Qf6h6 Nf3g1 Qh6g6 g2g3 Nf4e6 f2f4 e5xf4 g3xf4 Bc5xe3 Nc4xe3 Ne6c5 Bb3d5 Nc6e7 b2b4 Ne7xd5 Ne3xd5 Qg6xe4 Qc2xe4 Nc5xe4 Rf1e1 f7f5 Nd5xc7 Ra8a7 Ng1e2 Bc8d7
16/40 01:29 119.543.792 1.338.082 +0,17 Qf6h6 Nf3g1 Bc5xe3 Nc4xe3
16/40 01:32 123.715.615 1.338.385 +0,17 Nf4xg2
16/42 01:57 162.550.070 1.389.468 +0,17 Nf4xg2 Kh2xg2
17/47+ 03:46 316.721.335 1.401.803 +0,42 Nf4xg2
17/52 04:49 410.996.900 1.421.334 +1,00 Nf4xg2 Kh2xg2 Bc8xh3+ Kg2xh3 Qf6xf3+ Kh3h2 Ra8a6 Qc2d1 Qf3xe4 Rf1g1 Qe4h4+ Kh2g2 Nc6d4

Best,
Ignacio

[terminator]

Swamithan, are you the ladies champion from Asia who was on Chessbase? What is the white queen doing on c2 locked in by the bishop like that? Is this from a standard chess opening? I don't have a chess encyclopaedia BTW.