Monster move: 1...Nc3+!!

[Albert Silver]

This is a very tough move for most engines (did not try all). At least none of the top five had any luck in 10 minutes on my OCed quad.

[d]1rr3k1/3b1pq1/4p2p/1n1pP2P/2P2QP1/1p6/1P6/1K1RNB1R b - - 0 31

The winner is 1...Nc3+!!

[ZirconiumX]

A possible PV of Nc3+!! bxc3 b2 Kc2! b1=Q+ Rxb1 Rxb1 Kxb1. And Black has lost a piece for what compensation?

I'm not sure the passer is worth a piece, though. Especially one which has already been caught.

Matthew:out

[tano-urayoan]

A possible PV of Nc3+!! bxc3 b2 Kc2! b1=Q+ Rxb1 Rxb1 Kxb1. And Black has lost a piece for what compensation?

I'm not sure the passer is worth a piece, though. Especially one which has already been caught.

Matthew:out

After Kc2 Ba4+ wins.

[Cubeman]

Is the follow up after 2.bxc3 2..Qf8!?

[rjgibert]

Besides 1...Nc3+, there are 1...Qf8 and 1...Ra8 that win as well. There may be a 4th winning move, but 3 is already 2 too many.

[Ajedrecista]

Hello:

Is the follow up after 2.bxc3 2..Qf8!?

Once 31.- .., Nxc3+; 32.- bxc3 is played, this is what Spark 1.0 thinks:

[d]1rr3k1/3b1pq1/4p2p/3pP2P/2P2QP1/1pP5/8/1K1RNB1R b - - 0 32

Analysis by Spark 1.0 w32 (using two cores) in an Intel Pentium D930, with 1 GB of hash, running under Arena 2.0.1 GUI:

FEN: 1rr3k1/3b1pq1/4p2p/3pP2P/2P2QP1/1pP5/8/1K1RNB1R b - - 0 32

Spark-1.0-win32-mp:

1 00:00 42 0 -5,50 d5xc4 Rd1xd7 Qg7h7+ Kb1b2
1 00:00 110 0 -3,79 f7f5 e5xf6/ep
1 00:00 135 0 -2,08 b3b2 c4xd5 Rc8xc3
1 00:00 211 0 -1,94 Bd7c6
1 00:00 265 0 -1,87 Rb8a8 c4xd5 e6xd5

2/1 00:00 346 0 -1,87 Rb8a8 c4xd5 e6xd5

3/3 00:00 847 0 -1,87 Rb8a8 c4xd5 e6xd5
3/3 00:00 1.201 0 -1,81 Bd7c6 c4c5 Rb8a8

4/4 00:00 1.693 0 -1,99 Bd7c6 c4c5 Rb8a8 Ne1f3
4/4 00:00 2.700 0 -1,91 Rb8a8 Bf1d3 Ra8a2 Ne1f3

5/6 00:00 5.189 0 -1,87 Rb8a8 Bf1d3 Ra8a2 Ne1f3 Rc8a8 c4xd5 e6xd5
5/6 00:00 6.166 0 -1,85 Bd7c6 c4c5 Rb8a8 Ne1f3 Ra8a4

6/6- 00:00 13.732 0 -2,10 Bd7c6 c4c5 Rb8a8 Ne1f3 Ra8a4
6/8 00:00 22.860 0 -2,03 Rb8a8 c4xd5 e6xd5 Rd1xd5 Qg7xg4 Qf4xg4+ Bd7xg4

7/10 00:00 48.688 0 -1,79 Rb8a8 c4xd5 e6xd5 c3c4 Bd7xg4 Rd1xd5 Ra8a2

8/14 00:00 90.077 638.843 -1,83 Rb8a8 c4xd5 e6xd5 c3c4 Bd7xg4 Rd1xd5 Bg4e6 Rd5d2

9/14 00:00 197.888 666.289 -1,68 Rb8a8 c4xd5 e6xd5 Rd1xd5 Bd7c6 Bf1g2 Bc6xd5 Bg2xd5 Ra8a7 c3c4

10/20- 00:00 339.778 724.473 -1,93 Rb8a8 c4xd5 e6xd5 Rd1xd5 Bd7c6 Bf1g2 Bc6xd5 Bg2xd5 Ra8a7 c3c4
10/27+ 00:00 676.379 687.377 -1,43 Qg7f8 Rh1h2
10/27+ 00:01 777.653 691.247 -1,18 Qg7f8 Rh1h2
10/27 00:01 1.141.234 702.297 -1,63 Qg7f8 Bf1d3 Qf8a3 Qf4xh6 Qa3a2+ Kb1c1 b3b2+ Kc1d2 b2b1Q+ Ne1c2 Bd7e8 Rd1xb1 Rb8xb1 c4xd5

11/27+ 00:02 1.492.817 697.252 -1,38 Qg7f8 Bf1d3
11/27+ 00:02 1.527.151 703.108 -1,13 Qg7f8 Bf1d3
11/27 00:02 1.647.613 712.327 -1,02 Qg7f8 Bf1d3 Rb8a8 Rh1f1 Bd7b5 c4c5 Rc8xc5 Qf4b4 Bb5d7 Ne1g2 Qf8c8

12/27 00:03 2.201.471 726.318 -1,01 Qg7f8 Bf1d3 Rb8a8 Rh1f1 Bd7b5 c4c5 Rc8xc5 Qf4b4 Bb5d7 Ne1g2 Qf8c8 Qb4f4

13/31+ 00:04 3.429.093 759.320 -0,76 Qg7f8 Bf1d3
13/31+ 00:05 4.194.272 775.854 -0,51 Qg7f8 Bf1d3
13/31 00:06 5.162.434 790.450 -0,51 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a4 Bf1d3 Bd7b5 Qf4f6 Rc8a8 Kb1c1 d5xc4 Bd3b1 Qf8a3+ Rf2b2

14/36- 00:07 5.753.817 791.882 -0,76 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a4 Bf1d3 Bd7b5 Qf4f6 Rc8a8 Kb1c1 d5xc4 Bd3b1 Qf8a3+ Rf2b2
14/36 00:08 6.823.031 819.288 -0,81 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a4 Bf1d3 Rc8a8 Kb1c1 Bd7b5 g4g5 Bb5xc4 g5xh6 Ra4a1+ Bd3b1 Qf8a3+ Rf2b2

15/36+ 00:10 8.625.444 840.195 -0,56 Qg7f8 Rh1h2
15/36 00:13 11.173.025 829.536 -0,40 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a4 Kb1c1 Bd7b5 Kc1d2 Ra4a2+ Kd2e3 Bb5xc4 Rf2xa2 b3xa2 Ke3d2 Bc4xf1 Qf4xf1 Qf8a3 Ne1d3 Rc8xc3

16/36 00:31 26.590.750 835.845 -0,52 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a4 Kb1c1 Bd7b5 Kc1d2 Ra4a2+ Kd2e3 Bb5xc4 Ne1d3 Rc8a8 Nd3b4 Ra2xf2 Ke3xf2 Qf8c5+ Kf2g2

17/40 01:19 65.807.960 829.076 -0,46 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a4 Kb1c1 Ra4a1+ Kc1d2 b3b2 Bf1d3 d5xc4 Bd3e4 Bd7a4 Rd1b1 Rc8d8+ Kd2e3 Rd8d1 Rf2xb2 Rd1xe1+ Ke3f2 Ra1xb1 Rb2xb1

18/52+ 03:37 170.838.167 786.424 -0,21 Qg7f8 Rh1h2
18/52+ 04:50 229.049.146 788.421 +0,04 Qg7f8 Rh1h2
18/52 05:24 256.964.397 791.573 +0,39 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a7 Rd1d4 Rc8a8 Ne1c2 b3xc2+ Kb1xc2 Ra7a2+ Kc2d3 Ra2xf2 Qf4xf2 Ra8a3 Qf2b2 Qf8c5 Kd3e2 Qc5a7 Qb2b4 Ra3a2+ Ke2f3

19/52+ 07:08 345.226.247 806.162 +0,64 Qg7f8 Rh1h2
19/52+ 07:58 386.444.404 808.488 +0,89 Qg7f8 Rh1h2
19/52 08:36 421.135.457 814.673 +0,93 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a7 Rd1d4 Bd7c6 Ne1c2 b3xc2+ Kb1xc2 Qf8a3 Bf1d3 Rc8b8 Kc2d2 Qa3b2+ Kd2e3 Qb2c1+ Rf2d2 Rb8b2 Qf4f2 Ra7a2 Bd3h7+ Kg8f8 c4xd5 Qc1xc3+ Rd2d3

20/52 11:52 587.173.043 823.976 +0,93 Qg7f8 Rh1h2 Rb8a8 Rh2f2 Ra8a7 Rd1d4 Bd7c6 Ne1c2 b3xc2+ Kb1xc2 Qf8a3 Bf1d3 Rc8b8 Kc2d2 Qa3b2+ Kd2e3 Qb2c1+ Rf2d2 Rb8b2 Qf4f2 Ra7a2 Bd3h7+ Kg8f8 c4xd5 Qc1xc3+ Rd2d3

21/52+ 20:32 1.018.105.819 826.090 +1,18 Qg7f8 Rh1h2
21/52 29:25 1.463.712.132 829.041 +1,23 Qg7f8 Qf4f2 Rb8a8 Ne1d3 Rc8xc4 Qf2b2 Ra8a2 Qb2xb3 Ra2a3 Qb3b2 Rc4xc3 Nd3c1 Bd7a4 Rd1d2 Rc3xc1+ Kb1xc1 Qf8c5+ Kc1b1 Ra3b3 Rh1h3 Rb3xb2+ Rd2xb2 d5d4 Rb2b8+ Kg8g7
21/52 30:00 1.493.590.417 829.722 +1,23 Qg7f8 Qf4f2 Rb8a8 Ne1d3 Rc8xc4 Qf2b2 Ra8a2 Qb2xb3 Ra2a3 Qb3b2 Rc4xc3 Nd3c1 Bd7a4 Rd1d2 Rc3xc1+ Kb1xc1 Qf8c5+ Kc1b1 Ra3b3 Rh1h3 Rb3xb2+ Rd2xb2 d5d4 Rb2b8+ Kg8g7

I stopped the analysis after half an hour. I am curious to see Spark 1.0 analysis in faster hardware.

Regards from Spain.

Ajedrecista.

[zullil]

Besides 1...Nc3+, there are 1...Qf8 and 1...Ra8 that win as well. There may be a 4th winning move, but 3 is already 2 too many.

Critter-1.6a (8 threads, 4GB hash, MultiPV=3) likes Nc3+ much more than the other options:

Code: Select all

21/84  10:04    5809M   9604K  +2.33 Nc3+ bxc3 Qf8 Rh2 Ra8 c5 Rxc5 Qb4 Rca5 Qxf8+ Kxf8 Rdd2 Ra1+ Kb2 Rxe1 Bd3 Rxe5 c4 Re3 Bb1 Bc6 cxd5 Bxd5 Rd1 Kg7 Rf2 Ra4 Rg1 e5 g5 e4 gxh6+ Kxh6 Rf6+ Kh7 Rg2 Rh3 Rf5 Be6 Re5 Re3 Rb5

21/84  10:04    5809M   9604K  +1.04 Ra8 Rh3 Na3+ bxa3 Rxa3 cxd5 Rca8 dxe6 fxe6 Rhd3 Qe7 Rd6 Ra1+

21/84  10:04    5809M   9604K  +0.86 Qf8 Rh3 Ra8 Rxb3 Na3+ Rxa3 Rxa3 Rd2 Rb3 Nc2 Qg7 cxd5 exd5 Ne3 Qg5 Qxg5+ hxg5 Nxd5 Kg7 Nb6 Rxb6 Rxd7 Rc5 e6 Rxe6 Bd3 Rcc6 Ra7 Re1+ Ka2 Rg1 Bf5 Rb6 Bg6 Rg2

[Albert Silver]

Besides 1...Nc3+, there are 1...Qf8 and 1...Ra8 that win as well. There may be a 4th winning move, but 3 is already 2 too many.

Sorry, but that is incorrect. The difference between Nc3+ and the other moves is night and day.

[Albert Silver]

Besides 1...Nc3+, there are 1...Qf8 and 1...Ra8 that win as well. There may be a 4th winning move, but 3 is already 2 too many.

Critter-1.6a (8 threads, 4GB hash, MultiPV=3) likes Nc3+ much more than the other options:

Code: Select all

21/84  10:04    5809M   9604K  +2.33 Nc3+ bxc3 Qf8 Rh2 Ra8 c5 Rxc5 Qb4 Rca5 Qxf8+ Kxf8 Rdd2 Ra1+ Kb2 Rxe1 Bd3 Rxe5 c4 Re3 Bb1 Bc6 cxd5 Bxd5 Rd1 Kg7 Rf2 Ra4 Rg1 e5 g5 e4 gxh6+ Kxh6 Rf6+ Kh7 Rg2 Rh3 Rf5 Be6 Re5 Re3 Rb5

21/84  10:04    5809M   9604K  +1.04 Ra8 Rh3 Na3+ bxa3 Rxa3 cxd5 Rca8 dxe6 fxe6 Rhd3 Qe7 Rd6 Ra1+

21/84  10:04    5809M   9604K  +0.86 Qf8 Rh3 Ra8 Rxb3 Na3+ Rxa3 Rxa3 Rd2 Rb3 Nc2 Qg7 cxd5 exd5 Ne3 Qg5 Qxg5+ hxg5 Nxd5 Kg7 Nb6 Rxb6 Rxd7 Rc5 e6 Rxe6 Bd3 Rcc6 Ra7 Re1+ Ka2 Rg1 Bf5 Rb6 Bg6 Rg2

Great job. Indeed the main line is 1...Nc3+ 2.bxc3 Qf8 3.Rh2 Ra8 4.Rf2 Be8 (The best move, but may take it time to hit on it also.) 5.Qc1 Ra4 followed by Rca8 and it is over.

[zullil]

Besides 1...Nc3+, there are 1...Qf8 and 1...Ra8 that win as well. There may be a 4th winning move, but 3 is already 2 too many.

Critter-1.6a (8 threads, 4GB hash, MultiPV=3) likes Nc3+ much more than the other options:

Code: Select all

21/84  10:04    5809M   9604K  +2.33 Nc3+ bxc3 Qf8 Rh2 Ra8 c5 Rxc5 Qb4 Rca5 Qxf8+ Kxf8 Rdd2 Ra1+ Kb2 Rxe1 Bd3 Rxe5 c4 Re3 Bb1 Bc6 cxd5 Bxd5 Rd1 Kg7 Rf2 Ra4 Rg1 e5 g5 e4 gxh6+ Kxh6 Rf6+ Kh7 Rg2 Rh3 Rf5 Be6 Re5 Re3 Rb5

21/84  10:04    5809M   9604K  +1.04 Ra8 Rh3 Na3+ bxa3 Rxa3 cxd5 Rca8 dxe6 fxe6 Rhd3 Qe7 Rd6 Ra1+

21/84  10:04    5809M   9604K  +0.86 Qf8 Rh3 Ra8 Rxb3 Na3+ Rxa3 Rxa3 Rd2 Rb3 Nc2 Qg7 cxd5 exd5 Ne3 Qg5 Qxg5+ hxg5 Nxd5 Kg7 Nb6 Rxb6 Rxd7 Rc5 e6 Rxe6 Bd3 Rcc6 Ra7 Re1+ Ka2 Rg1 Bf5 Rb6 Bg6 Rg2

Great job. Indeed the main line is 1...Nc3+ 2.bxc3 Qf8 3.Rh2 Ra8 4.Rf2 Be8 (The best move, but may take it time to hit on it also.) 5.Qc1 Ra4 followed by Rca8 and it is over.

Here's Critter-1.6a with MultiPV=1, ie, standard search. Not an easy move to find quickly:

Code: Select all

23/59  03:24    2032M   9923K  +1.00 Ra8 Rh3 Na3+ bxa3 Qf8 Rxb3 Ba4 Rc3 Bxd1 Kc1 Rxa3 Rxa3 Qxa3+ Kxd1 Qa1+ Qc1 Qxe5 c5 Qd4+ Nd3 Qxg4+ Be2 Qg1+ Kd2 Qxc1+ Kxc1 f6 Bg4 Kf7 Kd2 Ke7 Ke3 Rg8 Bf3 Kd7 Nb4 Rg3 Kf4 Rg5 Ke3
23/59+ 12:49    8097M  10519K  +1.03 Nc3+ bxc3 Qf8 Rh2 Ra8 Rf2 Be8 Qc1 Ra4 Rb2 Ra1+ Kxa1 Qa3+ Kb1 Ra8 Nc2 Qa4 Na3 Qxa3
23/65+ 16:26   10390M  10533K  +1.16 Nc3+ bxc3 Qf8 Rh2 Ra8 Rf2 Be8 Qc1 Ra4 Rb2 Ra1+ Kxa1 Qa3+ Kb1 Ra8 Nc2 Qa4 Na3 Qxa3
23/74+ 21:12   13386M  10519K  +1.35 Nc3+ bxc3 Qf8 Rh2 Ra8 Rf2 Be8 Qc1 Ra4 Rb2 Ra1+ Kxa1 Qa3+ Kb1 Ra8 Nc2 Qa4 Na3 Qxa3
23/74+ 30:34   19324M  10536K  +1.63 Nc3+ bxc3 Qf8 Rh2 Ra8 Rf2 Be8 Qc1 Ra4 Rb2 Ra1+ Kxa1 Qa3+ Kb1 Ra8 Nc2 Qa4 Na3 Qxa3
23/85+ 53:53   34240M  10587K  +2.06 Nc3+ bxc3 Qf8 Rh2 Ra8 Rf2 Be8 Qc1 Ra4 Rb2 Ra1+ Kxa1 Qa3+ Kb1 Ra8 Nc2 Qa4 Qd2 bxc2+ Kc1 cxd1=Q+ Qxd1 Qa1+ Rb1 Qxc3+ Qc2 Qxe5 Be2 Bc6 cxd5 Bxd5 Kd1 Be4 Bd3 Bf3+ Kd2 Bxg4
23/85  80:44   51527M  10636K  +2.21 Nc3+ bxc3 Qf8 g5 Ra8 gxh6 Ra1+ Kxa1 Qa3+ Kb1 Qa2+ Kc1 b2+ Kd2 b1=Q+ Ke3 Qa7+ Rd4 Qc1+ Kf3 Qxf4+ Kxf4 f6 Nf3 fxe5+ Nxe5 Qb8 Rg1+ Kh8 Rg5 Rf8+ Kg3 Rxf1 Rdg4 Ba4 Kg2 Rf6 cxd5 exd5 Rxa4 Qb2+ Kh3 Qxc3+ Kg4 Qe3 Ng6+ Kh7 Rf4 Kxh6 Rgf5 Qg1+ Kh3 Re6 Ne5 Qh1+ Kg4 Qg2+ Kh4 Qh2+ Kg4 Qe2+ Nf3 Qg2+ Kh4
24/85+ 97:13   62395M  10695K  +2.34 Nc3+ bxc3 Qf8 g5 Ra8 gxh6 Ra1+ Kxa1 Qa3+ Kb1 Qa2+ Kc1 b2+ Kd2 b1=Q+ Ke3 Qa7+ Rd4 Qc1+ Kf3 Qxf4+ Kxf4 f6 Nf3 fxe5+ Nxe5 Qb8 Rg1+ Kh8 Rg5 Rf8+ Kg3 Rxf1 Rdg4 Ba4 Kg2 Rf6 cxd5 exd5 Rxa4 Qb2+ Kh3 Qxc3+ Kg4 Qe3 Ng6+ Kh7 Rf4 Kxh6 Rgf5 Qg1+ Kh3 Rxf5 Rxf5 Qh1+ Kg3
24/85  142:34   91795M  10730K  +2.54 Nc3+ bxc3 Qf8 g5 Ra8 gxh6 Ra1+ Kxa1 Qa3+ Kb1 Qa2+ Kc1 b2+ Kd2 b1=Q+ Ke3 Qa7+ Kd2 Qf5 Qg3+ Kf8 Nc2 Qff2+ Qxf2 Qxf2+ Be2 Qf4+ Ne3 Qxh6 Rdf1 dxc4 Rh4 Be8 Rff4 Rd8+ Ke1 Bb5 Kf2 Qg5 h6 Qxe5 h7 Ke7 Nxc4 Qxc3 Rf3 Qh8 Rd3 Ra8 Rd1 Bxc4 Bxc4
25/88- 151:33   98031M  10780K  +2.39 Nc3+ bxc3 Qf8 g5 Ra8 gxh6 Ra1+ Kxa1 Qa3+ Kb1 Qa2+ Kc1 b2+ Kd2 b1=Q+ Ke3 Qa7+ Kd2 Qf5 Qg3+ Kf8 Nc2 Qff2+ Qxf2 Qxf2+ Be2 Qf4+ Ne3 Qxh6 Rdf1 dxc4 Rh4 Be8 Rff4 Rd8+ Ke1 Bb5 Kf2 Qg5 h6 Qxe5 h7 Ke7 Nxc4 Qxc3 Rf3 Qh8 Rd3 Ra8 Rd1 Bxc4 Bxc4