Crushed!

[Jack Lad]

[d] rn1q1rk1/ppp2nbp/3p1pp1/4p2P/3PP1b1/2NBBN2/PPP1QPP1/2KR3R b - - 0 10
This position occured in a game I recently played and after white played h5 I naturally took the pawn with my bishop. White then took my bishop with his rook and after I took back with my pawn I was then crushed with an overwhelming attack against my exposed king starting with Bc4!. So can your engine avoid taking the pawn on h5 with the bishop?

[beachknight]

1569: rn1q1rk1/ppp2nbp/3p1pp1/4p2P/3
rn1q1rk1/ppp2nbp/3p1pp1/4p2P/3PP1b1/2NBBN2/PPP1QPP1/2KR3R b - - 0 1

Analysis by Rybka 3:

10...exd4 11.hxg6 hxg6[] 12.Bxd4 Nc6 13.Be3 Nce5 14.Bc4 c6 15.Bc5 Nxc4 16.Qxc4 b5 17.Qb3 dxc5 18.Rxd8 Raxd8 19.Rh4 Bc8 20.Ne2 Rfe8
+/- (1.00) Depth: 14 00:00:10 1873kN
10...exd4 11.hxg6 hxg6[] 12.Bxd4 Nc6 13.Be3 Nce5 14.Bc4 c6 15.Bc5 Nxc4 16.Qxc4 b5 17.Qb3 dxc5 18.Rxd8[] Raxd8 19.Ne2 Rfe8 20.Ng3 Bf8 21.Qc3 Kg7 22.Qa3
+/- (0.98) Depth: 15 00:00:26 4824kN
10...exd4 11.hxg6 hxg6[] 12.Bxd4[] Nc6 13.Be3 Nce5 14.Bc4 c6 15.Bc5 Nxc4 16.Qxc4 b5 17.Qb3 dxc5 18.Rxd8[] Raxd8 19.Ne2 Rfe8 20.Ng3 Bf8 21.Qc3 Kg7 22.Qa3
+/- (0.98) Depth: 16 00:00:34 6295kN
10...exd4 11.hxg6 hxg6[] 12.Bxd4[] Nc6 13.Be3 Nce5 14.Bc4 c6 15.Bc5 Nxc4 16.Qxc4 b5 17.Qb3 dxc5 18.Rxd8[] Raxd8 19.Ne2 Rfe8 20.Ng3 Bf8 21.Qc3 Kg7 22.Qa3
+/- (0.93) Depth: 17 00:01:06 12748kN
10...exd4 11.hxg6 hxg6[] 12.Bxd4[] Nc6 13.Bc4 Nxd4 14.Rxd4 Qd7 15.Qd2 Be6 16.Bxe6 Qxe6 17.Nh4 f5 18.exf5 gxf5 19.Rb4 Rab8 20.Re1 Ne5 21.f4 Rfe8 22.Re3 Bh6
+/- (0.98) Depth: 18 00:06:27 72965kN

(, chessengines20 23.07.2009)

[beachknight]

Latest line (quick analysis):

{Rybka 3:} 10... exd4 11. hxg6 hxg6 12. Bxd4 Nc6 13. Bc4 Nxd4 14. Rxd4 Qd7 15.
Qd2 Be6 16. Bxe6 Qxe6 17. Nh4 f5 18. exf5 gxf5 19. Rb4 Rab8 20. Re1 Ne5 21. f4
a5 22. Ra4 c6 23. g4 b5 24. gxf5 Qh6 25. Rae4 Qxh4 26. fxe5 Qh6 27. exd6 Qxd2+
28. Kxd2 Rbd8 29. Re6 Rxf5 30. Rg1 Kf8 31. Reg6 Bxc3+ 32. Kxc3 Kf7 33. Kb3 Rf3+
34. c3 Rd3 35. d7 R8xd7 36. Rxc6 R7d5 *

[Jack Lad]

Thanks Harun!

How about gxh5 instead?

[Eelco de Groot]

Thanks for the position Mc Mad!

It seemed a good opportunity for the first try-out of Stockfish 1.4 on my machine. Compared to Rybka's analysis, it is strange, Stockfish does not really consider exd4, only as the third move in the move list, but gxh5 is also not a certain draw when I look at the eval, so Rybka must be seeing something different here? Maybe deeper analysis is necessary with Rybka.

Freshly installed Stockfish 1.4 is fast in discarding Bxh5 as the best move, at one point Stockfish now almost reaches double the plydepth that Ancalagon reaches in the same time At least for build 189 in this position. This does not say everything, but it must be said that Jim Ablett's build of 32-bit Stockfish 1.4 seems certainly a bit faster in nodes per second than the Stockfish 1.3 32-bit. I have not made any measurements but compared to Ancalogon Stockfish 1.4 seems a faster compile. It could be partly because of better, faster code from Marco and Joona that a higher nodes per second now is reached. But Jim's executable is also a bit smaller now, only 167 kB where the old one was 276 kB. The 64-bit build Stockfish 1.4 is more than 5 times as large as the 32-bit! Is that because of other libraries needed or something like that? I would imagine the optimization does not differ a lot for 32-bit and 64-bit, things like loop unrolling etc. should be the same roughly...


[d]rn1q1rk1/ppp2nbp/3p1pp1/4p2P/3PP1b1/2NBBN2/PPP1QPP1/2KR3R b - -

Engine: Stockfish 1.4 JA (256 MB)
by Tord Romstad, Marco Costalba, Joona Kii

2.00 0:00 -1.03 1...Bxh5 2.Kb1 (4.538) 11

3.00 0:00 -0.46 1...Bxh5 2.Kb1 Nc6 (4.943) 12

4.00 0:00 -0.58 1...Bxh5 2.dxe5 Nxe5 3.Kb1 Nxd3
4.Qxd3 (7.483) 17

5.00 0:00 -0.34 1...Bxh5 2.Kb1 Nc6 3.Nb5 a5 (11.446) 27

6.00 0:00 -0.32 1...Bxh5 2.dxe5 fxe5 3.Kb1 Nc6 4.b3 (16.515) 37

7.00 0:00 -0.22 1...Bxh5 2.dxe5 fxe5 3.Kb1 Nc6 4.b3 Nd4 (25.271) 55

8.00 0:00 -0.28 1...Bxh5 2.d5 Nd7 3.Kb1 Ng5 4.b3 Nc5
5.Bxc5 Nxf3 (44.383) 88

9.00 0:00 -0.26 1...Bxh5 2.d5 Nd7 3.Kb1 Ng5 4.b3 a6
5.Rdg1 b5 (76.886) 140

10.00 0:00 -0.06 1...Bxh5 (216.765) 261

11.00 0:01 -0.22 1...Bxh5 2.Rdg1 exd4 3.Bxd4 c5 4.g4 cxd4
5.Nd5 Bh6+ 6.Kb1 Bxg4 7.Rxg4 Nc6 (576.793) 372

12.01 0:02 -0.22 1...Bxh5 2.Rdg1 exd4 3.Bxd4 c5 4.g4 cxd4
5.Nd5 Bh6+ 6.Kb1 Bxg4 7.Rxg4 Nc6
8.a3 (1.274.995) 436

13.01 0:06 -0.12 1...Bxh5 2.Rdg1 Bg4 3.d5 Nd7 4.Kb1 c6
5.Rh4 h5 6.b3 Nb6 7.Rgh1 cxd5 8.exd5 (2.920.387) 484

14.01 0:10 -0.32 1...Bxh5 2.dxe5 (5.412.109) 497

15.01 0:25 -0.62 1...Bxh5 2.dxe5 fxe5 3.Bc4 Bg4 4.Qd2 Nd7
5.Ng5 Bxd1 6.Qxd1 Nf6 7.Ne6 Qd7
8.Nxf8 Kxf8 9.Kb1 c6 (12.825.212) 512

15.02 0:38 -0.34 1...gxh5 2.d5 c6 3.Kb1 Nd7 4.b3 a6
5.Qe1 Nc5 6.Bc4 cxd5 7.Bxd5 Rc8
8.Na4 Nxa4 9.bxa4 (19.838.444) 512

16.01 1:48 -0.44 1...gxh5 2.Qe1 Nc6 3.Be2 a6 4.d5 Ne7
5.Nd2 f5 6.f3 f4 7.Bf2 Bd7 8.Rxh5 c6
9.Bc4 (55.550.546) 511

17.01 2:38 -0.46 1...gxh5 2.Qe1 Nc6 3.Be2 a6 4.d5 Ne7
5.Nd2 c6 6.dxc6 bxc6 7.f3 Be6 8.Rxh5 Ng5
9.Kb1 d5 (80.784.205) 511

18.01 4:56 -0.40 1...gxh5 2.Qe1 Nc6 3.Be2 f5 4.dxe5 fxe4
5.Nxe4 Qe7 6.Nf6+ Bxf6 7.exf6 Qxf6
8.Kb1 a6 9.b3 b5 10.Qd2 Nfe5 11.Nxe5 Qxe5 (150.422.002) 508

best move: g6xh5 time: 5:19.969 min n/s: 508.763 nodes: 162.780.268

Some of the latest Ancalagon builds:

rn1q1rk1/ppp2nbp/3p1pp1/4p2P/3PP1b1/2NBBN2/PPP1QPP1/2KR3R b - -

Engine: Ancalagon 1.3 Weak Squares 180 Board Control middle game 50 - endgame 50 Build 189 (Athlon 2009 MHz, 256 MB)
by Romstad, Costalba, Kiiski, de Groot

2.00 0:00 -0.90 1...Bxh5 2.Kb1 Nc6 (8.911) 33

3.00 0:00 -0.74 1...Bxh5 2.Kb1 Nc6 3.Bc4 exd4 4.Bxd4 Nxd4
5.Rxd4 (51.713) 143

4.00 0:00 -0.74 1...Bxh5 2.Kb1 Nc6 3.Bc4 exd4 4.Bxd4 Nxd4
5.Rxd4 (69.569) 177

5.00 0:00 -0.88 1...Bxh5 2.Kb1 Nc6 3.dxe5 fxe5 4.Bc4 (112.053) 238

6.00 0:00 -0.62 1...Bxh5 2.Kb1 Nc6 3.dxe5 fxe5 4.Bc4 Nd4 (255.794) 333

7.01 0:03 -0.50 1...Bxh5 2.Rxh5 gxh5 3.Rh1 c6 4.Nd2 h4
5.Qh5 (1.634.579) 460

8.01 0:04 -1.00 1...Bxh5 2.Rxh5 (2.228.649) 491

9.01 4:30 -1.43 1...Bxh5 2.Rxh5 gxh5 3.Bc4 h6 4.Rh1 Qd7
5.Rxh5 Qg4 6.Rh2 Nc6 (126.637.434) 468

9.02 4:44 -1.07 1...gxh5 2.Bc4 Nc6 3.Qd2 Qe8 4.dxe5 fxe5
5.Qd5 Kh8 (133.272.359) 469

10.01 6:02 -0.94 1...gxh5 2.Bc4 exd4 3.Bxd4 Nc6 4.Be3 f5
5.exf5 Qf6 6.Kb1 Rae8 7.Bb3 Qxf5 (170.703.220) 470

11.01 9:17 -1.07 1...gxh5 2.Qd2 Nc6 3.Bc4 f5 4.Bg5 Qe8
5.Bh6 f4 6.Bxg7 Kxg7 7.dxe5 Bxf3
8.gxf3 Qxe5 (262.875.785) 471

12.01 11:42 -1.21 1...gxh5 2.Qd2 Nc6 3.Bc4 f5 4.Bg5 Qd7
5.dxe5 fxe4 6.Nxe4 Ncxe5 7.Nxe5 Bxe5
8.Nf6+ Bxf6 9.Bxf6 Bxd1 10.Rxd1 (334.205.378) 476

13.01 21:20 -1.23 1...gxh5 2.Qd2 Nc6 3.Bc4 Na5 4.Be2 b6
5.Kb1 c6 6.Nh4 Bxe2 7.Qxe2 exd4
8.Rxd4 (611.630.780) 477

best move: g6xh5 time: 27:11.109 min n/s: 480.230 nodes: 783.210.236


Grrr, more than 4 minutes to find gxh5. But Ancalagon is more intended for long analysis times so it should not be a real surprise. The build-up of the plydepths is just very different. Stockfish prunes wherever possible and gets its strength from phenomenal plydepth. I think it is a bit like Rybka

rn1q1rk1/ppp2nbp/3p1pp1/4p2P/3PP1b1/2NBBN2/PPP1QPP1/2KR3R b - -

Engine: Ancalagon 1.3 WS180BC5050 Build 190 (256 MB)
by Romstad, Costalba, Kiiski, de Groot

2.00 0:00 -0.90 1...Bxh5 2.Kb1 Nc6 (8.911) 35

3.00 0:00 -0.74 1...Bxh5 2.Kb1 Nc6 3.Bc4 exd4 4.Bxd4 Nxd4
5.Rxd4 (52.288) 152

4.00 0:00 -0.74 1...Bxh5 2.Kb1 Nc6 3.Bc4 exd4 4.Bxd4 Nxd4
5.Rxd4 (73.693) 196

5.00 0:00 -0.88 1...Bxh5 2.Kb1 Nc6 3.dxe5 fxe5 4.Bc4 (118.583) 261

6.00 0:00 -0.62 1...Bxh5 2.Kb1 Nc6 3.dxe5 fxe5 4.Bc4 Nd4 (279.223) 364

7.01 0:04 -1.27 1...Bxh5 2.Rxh5 (1.952.643) 473

7.03 0:06 -1.26 1...gxh5 (2.870.856) 472

8.01 0:07 -1.27 1...gxh5 2.Kb1 Nc6 3.Bc4 exd4 4.Bxd4 Nxd4
5.Rxd4 Bh6 6.Nd5 (3.932.333) 492

8.02 0:08 -1.26 1...Bxh5 (4.057.784) 496

9.01 0:33 -1.52 1...Bxh5 2.dxe5 fxe5 3.Bc4 Qd7
4.Rxh5 gxh5 5.Ng5 Qg4 6.Bxf7+ Rxf7
7.Qc4 Qd7 8.Nxf7 Qxf7 (17.282.643) 516

9.02 0:38 -0.98 1...gxh5 2.Kb1 Nc6 3.Bc4 exd4 4.Bxd4 Nxd4
5.Rxd4 Bh6 6.Nd5 c6 (19.673.068) 509

10.01 2:05 -0.92 1...gxh5 2.Bc4 Nc6 3.Qf1 Na5 4.Kb1 c6
5.Be2 b5 6.Qe1 (60.775.163) 483

11.01 9:28 -1.09 1...gxh5 2.Qd2 Nc6 3.Bc4 Na5 4.Be2 a6
5.Kb1 b5 6.dxe5 fxe5 7.Nd5 (268.602.592) 472

12.01 17:57 -1.13 1...gxh5 2.Qd2 Nc6 3.dxe5 dxe5 4.Nh4 Nb4
5.Nf5 Nxd3+ 6.cxd3 Bxf5 7.exf5 Qd7
8.Rxh5 Rfd8 9.Qc2 Kf8 (508.498.953) 471

13.01 26:14 -1.15 1...gxh5 2.Qd2 Nc6 3.Bc4 f5 4.dxe5 fxe4
5.e6 exf3 6.exf7+ Kh8 7.g3 Qd7 8.Qd5 Ne5
9.Bb3 Qxf7 10.Qxb7 (744.852.418) 473

14.01 128:36 -1.35 1...gxh5 2.Qd2 (3.112.166.139) 403

The evaluation for 10...gxh5 seems to be sliding precariously away from a draw. It may be an illusion though, King Safety can give White a plus but it does not seem decisive if it is King Safety only, and King Safety scores are much larger in Ancalagon anyway.

Good testposition!

Eelco

[beachknight]

Thanks Harun!

How about gxh5 instead?

Just checked five lines.

White is winning

Best,

[Jack Lad]

Thanks for the position Mc Mad!

It seemed a good opportunity for the first try-out of Stockfish 1.4 on my machine. Compared to Rybka's analysis, it is strange, Stockfish does not really consider exd4, only as the third move in the move list, but gxh5 is also not a certain draw when I look at the eval, so Rybka must be seeing something different here? Maybe deeper analysis is necessary with Rybka.
[snipped]
The evaluation for 10...gxh5 seems to be sliding precariously away from a draw. It may be an illusion though, King Safety can give White a plus but it does not seem decisive if it is King Safety only, and King Safety scores are much larger in Ancalagon anyway.

Good testposition!

Eelco

Thanks for the analysis Eelco! I am glad that you found it useful too!