David Bronstein-Raymond Keene - Rxd5!!

[ZirconiumX]

Most engines evaluate this pretty high anyway, but which can find David Bronstein's move, Rxd5!!

[d]q1r2bk1/p2n3p/1p3pp1/2rb2N1/2p2Q2/1P4P1/PB3PBP/3RR1K1 w - - 2 23

Here is FruitFly 1.1 'Blackberry's opinion:

Score : +4.36
Depth : 15/1
Time : 00:03:08
Nodes : 31260000
N/sec : 166129
24. Qh4 fxg5 25. Qd4 c3 26. Bxc3 Kf7 27. Bxd5 Rxd5 28. Qxd5 Qxd5 29. Rxd5 Rc7 30. Kg2 Be7 31. h3 Nf6 32. Bxf6 Bxf6 33. Kf3

It's not hugely quick, as my GCC-4.6 is producing wierd results (GCC-4.0 does about 185knps on my comp from the starting position, whereas GCC-4.6 does about 50knps. As Julien put it 'Snail Pred', only fruitfly)

DiscoCheck 3.6 'Boney M' finds it quickly

Score : +2.80
Depth : 11/2
Time : 00:00:06
Nodes : 503868
N/sec : 81269
24. Rxd5 Rxd5 25. bxc4 fxg5 26. Qe3 Re8 27. Bxd5 Qxd5 28. cxd5 Rxe3 29. Rxe3

Quicker than stockfish, in fact.

Score : +3.79
Depth : 17/1
Time : 00:00:33
Nodes : 1811896
N/sec : 53979
24. Rxd5 Rxd5 25. bxc4 fxg5 26. Qe3 Re8 27. Bxd5 Qxd5 28. cxd5 Rxe3 29. fxe3 Bb4 30. Rb1 Kf7 31. e4 Bd6 32. Kf2 Ke7 33. Ke3 Ne5 34. Bxe5 Bxe5

Matthew:out

[jdart]

1.56 seconds for Arasan, latest build, Q9550 @ 3.2Ghz, 4 cores:

bm Rxd5
1 0.01 Bxf6 -2.43 108
1 0.05 Bxd5+ +0.36 264
1 0.05 Ne4 +0.44 607
1 0.05 Ne6 +0.48 742
2 0.06 Ne6 +0.48 5382
3 0.06 Ne6 +0.48 7855
4 0.06 Ne6 +0.36 18946
5 0.08 Ne4 +0.36 31563
6 0.08 Ne4! +0.73 36349
6 0.09 Ne4 +1.22 40266
7 0.09 Ne4 +1.38 48726
8 0.11 Ne4 +1.38 70707
9 0.12 Ne4! +1.75 108017
9 0.14 Ne4 +2.16 151724
10 0.16 Ne4 +2.24 219199
11 0.19 Ne4 +2.36 324176
12 0.30 Ne4! +2.73 623436
12 0.45 Ne4 +2.60 1028113
13 0.59 Ne4 +2.68 1467916
14 1.56 Rxd5 +2.70 4546085
15 1.91 Rxd5 +2.78 5615682
16 4.01 Rxd5 +2.78 12026872
17 8.06 Rxd5! +3.15 24253964
17 9.48 Rxd5 +3.34 28892706

[Dan Astrachan]

Ivanhoe prefers Qh4 here.


IvanHoe999946h (4-Gb hash) :

---------------------------------------------------------------------------
22 03:22 722 431 725 3 598 000 +4,73 Rd1xd5 Rc5xd5 Bb2xf6 Rd5-f5 Bg2xa8 Nd7xf6 Qf4-h4 c4xb3 Ba8-e4 Rc8-e8 a2xb3 h7-h6 Ng5-e6 Re8xe6 Be4-d5 Nf6xd5 Re1xe6 Kg8-f7 Re6-c6 Bf8-c5 Qh4xh6 Nd5-e7 Qh6-h7+ Kf7-e8 Rc6-e6 Bc5xf2+ Kg1-g2 Bf2-c5 Qh7xg6+ Ke8-d8 Qg6-g7 Rf5-f2+ Kg2-h3 Rf2-d2 Qg7-c3 Rd2-d4 Qc3-f3 Kd8-d7 Qf3-e2 Rd4-b4 Re6-e4 Ne7-d5 Re4xb4 Bc5xb4 Kh3-g2
23 03:22 722 431 725 3 598 000 +5,60 Qf4-h4 f6xg5 Qh4-d4 c4-c3 Bb2xc3 Kg8-f7 Qd4-h8 Rc5xc3 Bg2xd5+ Qa8xd5 Qh8xh7+ Bf8-g7 Rd1xd5 Rc3-c7 Rd5xg5 Nd7-f8 Qh7-h4 Bg7-f6 Qh4-f4 Rc7-d7 Rg5-e5 a7-a5 Kg1-g2 Rc8-c6 h2-h4 Rc6-d6 Qf4-c4+ Kf7-g7 Re5-e8 Rd6-d2 Qc4-c6 Rd2-d6 Qc6-c8 Bf6-d8 Re1-e2 Rd6-d3 Qc8-c6 Rd7-d6 Qc6-c4

[kgburcham]

[d] q1r2bk1/p2n3p/1p3pp1/2rb2N1/2p2Q2/1P4P1/PB3PBP/3RR1K1 w - - 2 23
seems David had several winning choices

Houdini
multi pv
27 29:10 +9.86 1.Bxf6 Qb8 2.Be5 Nxe5 3.Rxe5 Be6 (61.969.806.043) 35400
27 29:10 +8.95 1.Qh4 fxg5 2.Qd4 c3 3.Bxc3 Kf7 (61.969.806.043) 35400
26 29:10 +7.78 1.Rxd5 Rxd5 2.Bxf6 Rf5 3.Bxa8 Nxf6 (61.969.806.043) 35400
26 29:10 +6.46 1.Qd4 R8c7 2.Qe3 Ne5 3.Bxe5 fxe5 (61.969.806.043) 35400
26 29:10 +6.41 1.Nxh7 Kxh7 2.b4 Re8 3.Rxe8 Qxe8 (61.969.806.043) 35400
26 29:10 +4.42 1.Qg4 Qc6 2.Re6 Bxe6 3.Nxe6 Ne5 (61.969.806.043) 35400
26 29:10 +4.38 1.Ne4 Bxe4 2.Bxe4 Qb8 3.Rxd7 Qxf4 (61.969.806.043) 35400
26 29:10 +3.88 1.Qe3 Ne5 2.Rxd5 Rxd5 3.bxc4 Rxc4 (61.969.806.043) 35400

[Richard Allbert]

Big shock, latest Jabba actually gets this quickly, under a second, although 12s to start seeing a real advantage

Code: Select all

uci
id name JabbaCPP09072012
id author Richard Allbert
option name Hash type spin default 64 min 4 max 2048
option name Ponder type check default true
uciok
position fen q1r2bk1/p2n3p/1p3pp1/2rb2N1/2p2Q2/1P4P1/PB3PBP/3RR1K1 w - - 2 23
go infinite
info depth 1 score cp 7 time 0 nodes 432 pv g2d5 c5d5 b2f6 d7f6 f4f6 d5d1 e1d1 c4b3 a2b3
info depth 2 score cp 7 time 10 nodes 2456 pv g2d5 c5d5 b2f6 d7f6 f4f6 d5d1 e1d1 c4b3 a2b3
info depth 3 score cp -42 time 30 nodes 14013 pv g2d5 c5d5 b2f6 c4c3
info depth 4 score cp 24 time 80 nodes 46586 pv g5e4 c5c7 f4d2 d5e4 g2e4
info depth 5 score cp 32 time 200 nodes 122237 pv g5e4 c5a5 b3c4 g6g5 f4g4
info depth 6 score cp 48 time 380 nodes 242852 pv g5e4 c5b5 b3c4 b5b2 c4d5 b2a2 e4f6
info depth 7 score cp 108 time 829 nodes 544365 pv d1d5 c5d5 b3c4 f6g5 f4e3 d5e5 b2e5
info depth 8 score cp 144 time 1514 nodes 1013299 pv d1d5 c5d5 b3c4 f6g5 f4e3 f8c5 e3e6 g8f8 c4d5
info depth 9 score cp 185 time 5770 nodes 3949535 pv d1d5 c5d5 b3c4 f6g5 f4e3 d5e5 b2e5 f8c5 e3g5
info depth 10 score cp 235 time 12076 nodes 8546082 pv d1d5 c5d5 b3c4 f6g5 f4e3 d5f5 g2d5 a8d5 c4d5 f8b4 e3e6 f5f7
stop
bestmove d1d5 ponder c5d5

[zullil]

Most engines evaluate this pretty high anyway, but which can find David Bronstein's move, Rxd5!!

[d]q1r2bk1/p2n3p/1p3pp1/2rb2N1/2p2Q2/1P4P1/PB3PBP/3RR1K1 w - - 2 23

It seems that a top engine is one that realizes that Rxd5 is probably the third best move here.

Critter-1.6a (8 threads, 4GB hash, MultiPV=5):

Code: Select all

26/80  146:02  101046M  11532K  +8.49 Qh4 fxg5 Qd4 c3 Bxc3 Kf7 Ba1 Bh6 Bh3 g4 Bxg4 Rc4 bxc4 Rxc4 Qxd5+ Qxd5 Rxd5 Nc5 Rd7+ Nxd7 Be6+ Ke7 Bxc4+ Kd6 f4 Bf8 Bg8 h6 Re6+ Kc5 Rxg6 Kb5 Kg2 Kc5 Be6 Kd6 Bb3+ Ke7 Bd5 Nc5 f5 Kd7 Kf3 Ke7 f6+ Kd6 Bc4 Nd7 Kf4 Kc5 Be6 Kd6 Kf5 b5

25/80  146:02  101046M  11532K  +8.14 Bxf6 Qb8 Bxd5+ Rxd5 Be5 Nxe5 Rxd5 Qc7 Rdxe5 c3 Re8 Qxf4 gxf4 Rxe8 Rxe8 h6 Ne4 Kf7 Rc8 Bb4 Nxc3 h5 Nb5 a5 Rc7+ Ke6 Rc6+ Kf5 Rxb6 Bc5 Rc6 Be7 Nd4+ Kxf4 Rxg6 Ba3 Ra6 Bb4 Nc6 Kf3 Nxa5 Bc3 Nc6 Bg7 b4 Ke4

25/80  146:02  101046M  11532K  +6.21 Rxd5 Rxd5 Bxf6 Rf5 Bxa8 Nxf6 Qh4 h6 Ne4 Ne8 Bb7 Rc7 Qd8 Rxb7 Qxe8 Kg7 Qc8 Rff7 Qxc4 Kh7 Rd1 Bg7 Rd6 Rbe7 f4 Rf8 Qc2 Rf5 Qc6 Rff7 Rxg6 Rc7 Qd6 Rc1+ Kg2 Rc2+ Nf2 Rxa2

25/80  146:02  101046M  11532K  +6.12 Nxh7 Kxh7 b4 Re8 Rxe8 Qxe8 bxc5 Bxg2 Kxg2 Qa8+ Kg1 Qc6 Qh4+ Kg8 Qg4 Ne5 Bxe5 fxe5 Rd7 b5

25/80  146:02  101046M  11532K  +4.58 Qg4 Qc6 Nxh7 Kxh7 Qh3+ Kg8 Rxd5 Rxd5 bxc4 Rh5 Bxc6 Rxh3 Bxd7 Rxg3+ fxg3 Rc7 Be6+ Kg7 Bd5 Re7 Rf1 Re2 Bxf6+ Kh6 Bd4 Bc5 Bxc5 bxc5 Rf2 Re1+ Kg2 Re3 Rd2 Kg5 Kf2 Rc3 Re2 Ra3 Kg2 Kf5 h4 Rc3 a4 Ra3 Rf2+ Ke5

[Kingghidorah]

Hannibal 1.2 64b finds it instantly

[lucasart]

Most engines evaluate this pretty high anyway, but which can find David Bronstein's move, Rxd5!!

[d]q1r2bk1/p2n3p/1p3pp1/2rb2N1/2p2Q2/1P4P1/PB3PBP/3RR1K1 w - - 2 23

It seems that a top engine is one that realizes that Rxd5 is probably the third best move here.

Critter-1.6a (8 threads, 4GB hash, MultiPV=5):

Code: Select all

26/80  146:02  101046M  11532K  +8.49 Qh4 fxg5 Qd4 c3 Bxc3 Kf7 Ba1 Bh6 Bh3 g4 Bxg4 Rc4 bxc4 Rxc4 Qxd5+ Qxd5 Rxd5 Nc5 Rd7+ Nxd7 Be6+ Ke7 Bxc4+ Kd6 f4 Bf8 Bg8 h6 Re6+ Kc5 Rxg6 Kb5 Kg2 Kc5 Be6 Kd6 Bb3+ Ke7 Bd5 Nc5 f5 Kd7 Kf3 Ke7 f6+ Kd6 Bc4 Nd7 Kf4 Kc5 Be6 Kd6 Kf5 b5

25/80  146:02  101046M  11532K  +8.14 Bxf6 Qb8 Bxd5+ Rxd5 Be5 Nxe5 Rxd5 Qc7 Rdxe5 c3 Re8 Qxf4 gxf4 Rxe8 Rxe8 h6 Ne4 Kf7 Rc8 Bb4 Nxc3 h5 Nb5 a5 Rc7+ Ke6 Rc6+ Kf5 Rxb6 Bc5 Rc6 Be7 Nd4+ Kxf4 Rxg6 Ba3 Ra6 Bb4 Nc6 Kf3 Nxa5 Bc3 Nc6 Bg7 b4 Ke4

25/80  146:02  101046M  11532K  +6.21 Rxd5 Rxd5 Bxf6 Rf5 Bxa8 Nxf6 Qh4 h6 Ne4 Ne8 Bb7 Rc7 Qd8 Rxb7 Qxe8 Kg7 Qc8 Rff7 Qxc4 Kh7 Rd1 Bg7 Rd6 Rbe7 f4 Rf8 Qc2 Rf5 Qc6 Rff7 Rxg6 Rc7 Qd6 Rc1+ Kg2 Rc2+ Nf2 Rxa2

25/80  146:02  101046M  11532K  +6.12 Nxh7 Kxh7 b4 Re8 Rxe8 Qxe8 bxc5 Bxg2 Kxg2 Qa8+ Kg1 Qc6 Qh4+ Kg8 Qg4 Ne5 Bxe5 fxe5 Rd7 b5

25/80  146:02  101046M  11532K  +4.58 Qg4 Qc6 Nxh7 Kxh7 Qh3+ Kg8 Rxd5 Rxd5 bxc4 Rh5 Bxc6 Rxh3 Bxd7 Rxg3+ fxg3 Rc7 Be6+ Kg7 Bd5 Re7 Rf1 Re2 Bxf6+ Kh6 Bd4 Bc5 Bxc5 bxc5 Rf2 Re1+ Kg2 Re3 Rd2 Kg5 Kf2 Rc3 Re2 Ra3 Kg2 Kf5 h4 Rc3 a4 Ra3 Rf2+ Ke5

+1

Anyway, when one has an overwhelming advantage like this, many paths lead to Rome... Then it's just a question of personal preference. Personally, I think that Qh4 is the most beautiful one

[Dan Astrachan]

After 4 hours of analysis, Ivanhoe still thinks Qh4 is the best move here:

Code: Select all

 30	3:43:18	164 847 290 097	12 304 000	+7,89	Qf4-h4 f6xg5 Qh4-d4 c4-c3 Bb2xc3 Kg8-f7 Qd4-h8 Rc5xc3 Bg2xd5+ Qa8xd5 Qh8xh7+ Bf8-g7 Rd1xd5 Nd7-f6 Re1-e7+ Kf7xe7 Qh7xg7+ Ke7-e6 Rd5xg5 Rc8-g8 Qg7xa7 Rc3-c1+ Kg1-g2 Rc1-c6 Qa7-b7 Rg8-c8 Qb7-g7 Rc8-g8 Qg7-a7 Nf6-d7 Qa7-a4 Ke6-d6 h2-h4 Nd7-f6 Qa4-b5 Kd6-c7 Qb5-d3 Rg8-d8 Qd3xg6 Rd8-d2 Qg6-f5 Nf6-e8 Qf5-f4+ Rd2-d6 Rg5-g6 Kc7-d7 Rg6xd6+ Rc6xd6 h4-h5 Rd6-f6 Qf4-g5 Rf6-f8 Qg5-b5+ Kd7-e7 Qb5xb6 Rf8-h8 h5-h6 

Position after this variation, Black to play:

[d]4n2r/4k3/1Q5P/8/8/1P4P1/P4PK1/8 b - - 0 51

[zullil]

After 4 hours of analysis, Ivanhoe still thinks Qh4 is the best move here:

Code: Select all

 30	3:43:18	164 847 290 097	12 304 000	+7,89	[b]Qf4-h4 [/b]f6xg5 Qh4-d4 c4-c3 Bb2xc3 Kg8-f7 Qd4-h8 Rc5xc3 Bg2xd5+ Qa8xd5 Qh8xh7+ Bf8-g7 Rd1xd5 Nd7-f6 Re1-e7+ Kf7xe7 Qh7xg7+ Ke7-e6 Rd5xg5 Rc8-g8 Qg7xa7 Rc3-c1+ Kg1-g2 Rc1-c6 Qa7-b7 Rg8-c8 Qb7-g7 Rc8-g8 Qg7-a7 Nf6-d7 Qa7-a4 Ke6-d6 h2-h4 Nd7-f6 Qa4-b5 Kd6-c7 Qb5-d3 Rg8-d8 Qd3xg6 Rd8-d2 Qg6-f5 Nf6-e8 Qf5-f4+ Rd2-d6 Rg5-g6 Kc7-d7 Rg6xd6+ Rc6xd6 h4-h5 Rd6-f6 Qf4-g5 Rf6-f8 Qg5-b5+ Kd7-e7 Qb5xb6 Rf8-h8 h5-h6 

Here's what Critter-1.6a has after 500 minutes (8 threads, 4GB hash, MultiPV=5)

Code: Select all

27/80  499:47  351287M  11714K  +8.60 Qh4 fxg5 Qd4 c3 Bxc3 Kf7 Ba1 Bh6 Bh3 g4 Bxg4 Rc4 bxc4 Rxc4 Qxd5+ Qxd5 Rxd5 Nc5 Rd7+ Nxd7 Be6+ Ke7 Bxc4+ Kd6 f4 Bf8 Bg8 h6 Re6+ Kc7 Rxg6 Kb7 Bd5+ Kc8 Kf2 Kd8 f5 Ke7 Kf3 Kd8 Kf4 b5 Bd4 a5 g4 Kc7 h4 Bd6+ Ke4

27/80  499:47  351287M  11714K  +8.57 Bxf6 Qb8 Bxd5+ Rxd5 Be5 Nxe5 Rxd5 Qc7 Rdxe5 c3 Re8 Qxf4 gxf4 Rxe8 Rxe8 h6 Ne4 Kf7 Rc8 b5 Nxc3 b4 Nd5 Bd6 Rc6 Ke6 Nxb4 Kd7 Rc4 g5 Nd3 gxf4 Nxf4 Be7 Nd3 Bd8 Kg2 h5 Rd4+ Ke8 Nf4 Bb6 Re4+ Kf7 Nxh5 Kg6 Ng3 Bd8 Re6+ Kf7 Rd6

27/80  499:47  351287M  11714K  +6.56 Nxh7 Kxh7 b4 Re8 Rxe8 Qxe8 bxc5 Bxg2 Kxg2 Bxc5 Qc7 Qe4+ Kg1 Bxf2+ Kxf2 Qf5+ Kg1 Qc5+ Qxc5 Nxc5 Bxf6 b5 Kg2 Nd3 Kf3 Kh6 h4 a6 Bg5+ Kg7 Ke3 Nb4 Rd7+ Kf8 a3 Na2 Kd2 a5 Rb7 b4 Be7+ Ke8 axb4 axb4 Bxb4 Nxb4 Rxb4

27/80  499:47  351287M  11714K  +6.50 Rxd5 Rxd5 Bxf6 Rf5 Bxa8 Nxf6 Qh4 Rxa8 Qxc4+ Nd5 Qc6 Rd8 h4 Ne7 Qe6+ Kg7 g4 Rf6 Qe5 Rd6 Ne4 Re6 Qa1 Rxe4 Rxe4 Kf7 Qe5 h6 Qc7 a5 Kg2 g5 hxg5 hxg5 Re5 Ke8 Qc4 Kd7 Rxg5 Re6 Qa6 Rc6 Qb7+ Ke8 Rb5 Rc2 Qxb6 Nc6 Qe3+ Be7

27/80  499:47  351287M  11714K  +4.78 Qg4 Qc6 Nxh7 Kxh7 Qh3+ Kg8 Rxd5 Rxd5 bxc4 Rd6 Bxc6 Rcxc6 Re8 Rc7 Rd8 Kg7 g4 Rc5 Ba3 Ne5 Ra8 Nf7 Bxc5 Rd1+ Kg2 Bxc5 g5 fxg5 Rxa7 Rd6 Qc3+ Bd4 Qg3 Rf6 f3 Rf5 Qd6 Bc5 Qe6 Rf4 Qe5+ Kh6 Qe8 Kg7 Qe6 Rf5 Rd7 Rf4 Qe5+ Kf8 Qd5 Rf5 Qb7 Kg7 a4 Rf6 Qd5 Rf5 Qe6 Rf4 a5 Rf6

I'll do a standard search if I get a chance.