Exchange sac

Tord Romstad · Post by **Tord Romstad** » Fri May 02, 2008 12:48 am

A curious fact about the new Glaurung is that it loves to sacrifice the exchange. I don't know why; I haven't changed the material values or anything else that should affect the program's willingness to part with an exchange. Whatever the reason is, I now see Glaurung make unclear or dubious exchange sacrifices all the time.

The following one looked so strange at first that I thought I had a bug:

[D]4r1k1/ppq1rppp/2pb2n1/3p2Pn/3P4/1P1BP2P/P1P1N3/R1B2RQK b - -

Glaurung (black) surprised me by playing 23... Re4!? This was almost certainly played as a positional sacrifice. The game was played at a time control of two minutes per game, with one second increment, on a single core of a 2.8 GHz Core Duo CPU. I doubt that Glaurung would see any very deep tactics at such a fast time control.

Do any other engines like Re4 here? Is it really a strong move? If it is, is it possible to explain the point of the sacrifice in terms an average human player can understand, without giving a ton of variations?

If I recall correctly, Glaurung's score at this stage of the game was about +1.5. Glaurung went on to win quite quickly and convincingly, but perhaps because of mistakes by the opponent. The full game:

Code: Select all

&#91;Event "Computer chess game"&#93;
&#91;Site "cm-84.215.94.43.getinternet.no"&#93;
&#91;Date "2008.05.02"&#93;
&#91;Round "2"&#93;
&#91;White "Toga II 1.4.1SE"&#93;
&#91;Black "Glaurung 080502"&#93;
&#91;Result "0-1"&#93;
&#91;TimeControl "120+1"&#93;

1. f4 d5 2. Nf3 Nf6 3. b3 Bg4 4. e3 e6 5. Bb5+ Nbd7 6. O-O c6 7. Be2 Rc8 8.
Bb2 Be7 9. h3 Bxf3 10. Bxf3 O-O 11. Nc3 Re8 12. Qe1 e5 13. fxe5 Nxe5 14.
Be2 Bd6 15. Qf2 Qc7 16. Kh1 Ng6 17. g4 Be5 18. d4 Bg3 19. Qg1 Bd6 20. Bd3
Re7 21. g5 Nh5 22. Ne2 Rce8 23. Bc1 Re4 24. Bxe4 Rxe4 25. Qf2 Qd7 26. Qf5
Qe8 27. Qf2 Nh4 28. Kg1 Qe7 29. Bd2 Qxg5+ 30. Kh1 Qg6 31. Rg1 Qe6 32. Qf1
Nf5 33. Qf3 Nfg3+ 34. Kg2 Rh4 35. Nxg3 Nxg3 36. Raf1 Qxh3+ 37. Kf2 Ne4+ 38.
Ke1 Qxf3 39. Rxf3 Rh2 40. Ba5 b6 41. Bc3 Rxc2 42. Kd1 Rxc3 43. Rg2 h5 44.
Rh3 Bf4 45. Re2 g5 46. Rf3 Kg7 47. Rh3 g4 48. Rxh5
&#123;White resigns&#125; 0-1

Tord

Terry McCracken · Post by **Terry McCracken** » Fri May 02, 2008 1:01 am

Tord Romstad wrote:A curious fact about the new Glaurung is that it loves to sacrifice the exchange. I don't know why; I haven't changed the material values or anything else that should affect the program's willingness to part with an exchange. Whatever the reason is, I now see Glaurung make unclear or dubious exchange sacrifices all the time.

The following one looked so strange at first that I thought I had a bug:

[D]4r1k1/ppq1rppp/2pb2n1/3p2Pn/3P4/1P1BP2P/P1P1N3/R1B2RQK b - -

Glaurung (black) surprised me by playing 23... Re4!? This was almost certainly played as a positional sacrifice. The game was played at a time control of two minutes per game, with one second increment, on a single core of a 2.8 GHz Core Duo CPU. I doubt that Glaurung would see any very deep tactics at such a fast time control.

Do any other engines like Re4 here? Is it really a strong move? If it is, is it possible to explain the point of the sacrifice in terms an average human player can understand, without giving a ton of variations?

If I recall correctly, Glaurung's score at this stage of the game was about +1.5. Glaurung went on to win quite quickly and convincingly, but perhaps because of mistakes by the opponent. The full game:
Code: Select all
&#91;Event "Computer chess game"&#93;
&#91;Site "cm-84.215.94.43.getinternet.no"&#93;
&#91;Date "2008.05.02"&#93;
&#91;Round "2"&#93;
&#91;White "Toga II 1.4.1SE"&#93;
&#91;Black "Glaurung 080502"&#93;
&#91;Result "0-1"&#93;
&#91;TimeControl "120+1"&#93;

1. f4 d5 2. Nf3 Nf6 3. b3 Bg4 4. e3 e6 5. Bb5+ Nbd7 6. O-O c6 7. Be2 Rc8 8.
Bb2 Be7 9. h3 Bxf3 10. Bxf3 O-O 11. Nc3 Re8 12. Qe1 e5 13. fxe5 Nxe5 14.
Be2 Bd6 15. Qf2 Qc7 16. Kh1 Ng6 17. g4 Be5 18. d4 Bg3 19. Qg1 Bd6 20. Bd3
Re7 21. g5 Nh5 22. Ne2 Rce8 23. Bc1 Re4 24. Bxe4 Rxe4 25. Qf2 Qd7 26. Qf5
Qe8 27. Qf2 Nh4 28. Kg1 Qe7 29. Bd2 Qxg5+ 30. Kh1 Qg6 31. Rg1 Qe6 32. Qf1
Nf5 33. Qf3 Nfg3+ 34. Kg2 Rh4 35. Nxg3 Nxg3 36. Raf1 Qxh3+ 37. Kf2 Ne4+ 38.
Ke1 Qxf3 39. Rxf3 Rh2 40. Ba5 b6 41. Bc3 Rxc2 42. Kd1 Rxc3 43. Rg2 h5 44.
Rh3 Bf4 45. Re2 g5 46. Rf3 Kg7 47. Rh3 g4 48. Rxh5
&#123;White resigns&#125; 0-1
Tord

There's nothing wrong with that sacrifice, it's sound and I'd say winning outright due to the weaking of White's King position.

Tord, where can I download this latest version you're using here?

Best,
Terry

genorb · Post by **genorb** » Fri May 02, 2008 1:31 am

Some fast analysis

Hash 256 Mb
1 CPU 32 bits

Actually Glaurung 2.0.1 could also play Re4 under fast time control but then change his mind later to Nh4.

Naum 3.1 likes Re4 very quickly and gets a good score for black. Rybka 2.3.2a and Hiarcs prefer to play first Nh4 and then Re4.

But Rybka Winfinder 2.2, which is very very good at tactics, prefers also Re4. So I would guess that Re4 is a good move (perhaps the best) and tricky enough not to be obvious for all engines.

Zappa Mexico prefers also Nh4 but it doesn't want to play Re4 afterwards. The same goes for Shredder 11.

Of course everything could be different with longer analysis...

Glaurung 2.0.1

2.00 0:00 -1.17 1...Nh4 2.Bd2 (352) 1
2.00 0:00 -1.39 1...Qa5 2.a4 (466) 1
2.00 0:00 -1.43 1...Qd7 2.Qg2 (698) 2
3.00 0:00 -1.35 1...Qd7 2.Qg2 Nh4 (1.105) 3
4.00 0:00 -1.01 1...Qd7 2.Bf5 Qc7 3.Bd2 (3.409) 9
4.00 0:00 -1.03 1...Qc8 2.Bf5 Qa8 3.Bd2 (5.393) 14
5.00 0:00 -1.21 1...Qc8 2.Bf5 Qc7 3.Qg4 Ng3+ 4.Nxg3 Bxg3 (8.661) 23
6.00 0:00 -1.17 1...Qc8 2.Bf5 Qb8 3.Bd2 Nh4 4.Bd3 (13.677) 35
7.00 0:00 -1.17 1...Qc8 2.Bf5 Qb8 3.Qg4 Ng3+ 4.Nxg3 Bxg3 5.Bd7 Rd8 (22.404) 55
8.00 0:00 -0.72 1...Qc8 2.Qg4 Ng3+ 3.Nxg3 Qxg4 4.hxg4 Bxg3 5.Kg2 Bd6 6.Bd2 (47.127) 107
9.00 0:00 -0.88 1...Qc8 2.Qg4 Ng3+ 3.Nxg3 Qxg4 4.hxg4 Bxg3 5.Kg2 Bh4 6.Rf5 Be1 (164.732) 270
10.00 0:00 -0.56 1...Qc8 2.Qg4 Ng3+ 3.Nxg3 Qxg4 4.hxg4 Bxg3 5.Bd2 Nh4 6.c4 Rc8 7.cxd5 cxd5 (264.760) 353
11.01 0:01 -0.54 1...Qc8 2.Qg4 Ng3+ 3.Nxg3 Qxg4 4.hxg4 Bxg3 5.Bd2 Bd6 6.Kg2 Re6 7.c4 Nh4+ 8.Kf2 (760.793) 529
12.01 0:03 -0.31 1...Qc8 2.Qg4 Ng3+ 3.Nxg3 Qxg4 4.hxg4 Bxg3 5.Bd2 Bd6 6.Kg2 Re6 7.c4 Ne7 8.cxd5 Nxd5 (2.202.659) 640
12.02 0:03 -0.54 1...Re4 2.Bxe4 Rxe4 3.Qf2 Nh4 4.Kg1 Qe7 5.Kh1 b6 6.c4 Qd7 7.Nf4 Nxf4 8.Qxh4 Nxh3 (2.389.526) 648
13.01 0:06 -0.54 1...Re4 2.Bxe4 Rxe4 3.Qf2 Nh4 4.Kg1 Qe7 5.Kh1 Qe6 6.Kg1 Qg6 7.Kh1 Qxg5 8.Qxf7+ Kh8 9.Qxb7 (4.675.079) 680
14.01 0:11 -0.54 1...Re4 2.Bxe4 Rxe4 3.Qf2 Nh4 4.Kg1 Qe7 5.Kh1 Qe6 6.Kg1 Qg6 7.Kh1 Qxg5 8.Qxf7+ Kh8 9.Qxb7 (7.973.760) 697
15.01 0:21 -0.45 1...Re4 2.Bxe4 Rxe4 3.Qf2 Nh4 4.Nf4 Bxf4 5.exf4 Ng6 6.Re1 Nhxf4 7.Rxe4 dxe4 8.Bxf4 Qxf4 9.Rf1 Qxf2 10.Rxf2 e3 (14.507.862) 689
16.01 0:45 -0.45 1...Re4 2.Bxe4 Rxe4 3.Qf2 Nh4 4.Nf4 Bxf4 5.exf4 Ng6 6.Re1 Nhxf4 7.Rxe4 dxe4 8.Bxf4 Qxf4 9.Rf1 Qxf2 10.Rxf2 e3 11.Re2 (32.409.180) 709
16.02 0:58 -1.25 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rf2 Nhg3+ 6.Kg2 Rxe3 7.Bxe3 Nxe3+ 8.Kxg3 Nxg4 9.Kxg4 Qd7+ 10.Kg3 Qf5 (41.890.507) 714
17.01 1:11 -1.23 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxf4 6.Qxf5 Ne2 7.Bd2 Bh2 8.Rg2 Ng3+ 9.Rxg3 Bxg3 10.Rf1 (51.336.741) 722
18.01 1:42 -1.13 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxf4 6.Qxf5 Ne2 7.Bd2 Ng3+ 8.Rxg3 Bxg3 9.c4 g6 10.Qf3 Bh2 11.cxd5 cxd5 (74.413.686) 727

Naum 3.1

1/12 0:00 -0.65 1...Qd7 (2.202) 2202
2/13 0:00 -0.40 1...Qd7 2.Bf5 (6.979) 436
3/15 0:00 -0.02 1...Qd7 2.Bf5 Re6 (8.481) 530
3/15 0:00 -0.15 1...Nh4 2.Qg4 Ng3+ (9.523) 595
3/15 0:00 -0.28 1...Ng3+ 2.Nxg3 Bxg3 (14.922) 481
4/15 0:00 -0.38 1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 (21.763) 702
5/19 0:00 -0.22 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 (37.788) 599
5/19 0:00 -0.27 1...Qc8 2.Bf5 Qb8 3.Qg4 Ng3+ (43.692) 693
6/17 0:00 -0.16 1...Qc8 2.Bf5 Qb8 3.Qg4 Ng3+ 4.Nxg3 (49.966) 640
6/17 0:00 -0.28 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 (58.968) 627
7/20 0:00 -0.28 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 Qd6 (89.499) 715
8/25 0:00 -0.22 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 Qd6 5.a3 (158.513) 780
8/25 0:00 -0.25 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Bd2 Kh8 5.a4 (192.315) 769
9/25 0:00 -0.07 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Bd2 g6 5.Rf6 Re6 (312.842) 834
9/28 0:00 -0.11 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 Qd6 5.a3 dxc4 (389.636) 860
10/30 0:00 -0.13 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 Kh8 5.cxd5 cxd5 6.Rac1 (667.215) 927
11/31 0:01 -0.09 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.a3 g6 5.c4 dxc4 6.bxc4 Rd8 (1.763.619) 932
11/33 0:02 -0.39 1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 Nh4 6.Qg1 Bd6 (2.884.733) 976
12/26 0:03 -0.36 1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 Nh4 6.Qg1 Bd6 7.Rf2 (3.354.021) 980
13/27 0:04 -0.33 1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 Nh4 6.Qg1 Bd6 7.Qf2 Qd7 (4.811.163) 1022
14/30 0:07 -0.26 1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 Nh4 6.Qg1 Bd6 7.Qf2 Qd7 8.Kg1 (7.437.719) 1062
15/31 0:12 -0.40 1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 Nh4 6.Qg1 Bd6 7.Qf2 Qd7 8.Kg1 Qe7 (13.222.704) 1086
16/39 0:41 -0.71 1...Re4 2.Qf2 Qd7 3.Qf5 Qxf5 4.Rxf5 Rxe3 5.Bxe3 Rxe3 6.Rf2 Nh4 7.Kg1 Rxh3 8.Bf5 Nxf5 9.Rxf5 (44.178.851) 1067
17/36 0:57 -0.69 1...Re4 2.Qf2 Qd7 3.Qf5 Qxf5 4.Rxf5 Rxe3 5.Bxe3 Rxe3 6.Rf2 Nh4 7.Kg1 Rxh3 8.Bf5 Nxf5 9.Rxf5 Re3 (63.102.163) 1089
18/45 1:47 -1.05 1...Re4 2.Qf2 Ng3+ 3.Nxg3 Bxg3 4.Qg2 Nh4 5.Qg1 Bd6 6.Bxe4 Rxe4 7.Rf2 Qd7 8.Qf1 Bg3 9.Re2 Qe7 10.Qg1 (119.074.700) 1105

Rybka Winfinder 2.2

4.00 0:00 -0.31 1...Ng3+ (2.250) 48
5.00 0:00 -0.18 1...Ng3+ 2.Nxg3 (4.412) 57
6.00 0:00 -0.12 1...Ng3+ 2.Nxg3 Bxg3 3.c4 (12.214) 61
6.00 0:00 -0.18 1...Nh4 2.Qg4 (13.181) 61
7.00 0:00 -0.12 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 (20.638) 64
7.00 0:00 -0.15 1...c5 64
7.00 0:00 -0.18 1...c5 64
7.00 0:00 -0.12 1...c5 64
7.00 0:00 -0.18 1...c5 2.Qg4 c4 3.Bxc4 dxc4 (29.183) 63
8.00 0:00 -0.18 1...c5 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Bb5 Re4 (63.051) 65
9.00 0:01 -0.06 1...c5 2.dxc5 Bxc5 3.Qg4 Qe5 4.Rb1 Bd6 (113.410) 65
9.00 0:02 -0.18 1...Ng3+ 2.Nxg3 Bxg3 3.c4 Nh4 4.cxd5 cxd5 5.Bd2 (131.455) 66
10.00 0:03 -0.25 1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bd6 4.Qe1 Qb6 5.Bb2 (207.752) 67
11.00 0:04 -0.25 1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bd6 4.Qe1 c5 5.Bb2 Qc6 (324.281) 68
12.01 0:08 -0.18 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.a3 Kh8 5.c4 dxc4 6.bxc4 (592.623) 70
12.03 0:12 -0.43 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rf2 Nxf4 6.Qxf5 (822.011) 69
13.01 0:15 -0.43 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxf4 6.Qxf5 Ne2 (1.105.131) 70
13.31 0:26 -0.62 1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 Nh4 6.Qg1 Bd6 7.Qf2 (1.861.360) 71
14.01 0:31 -0.81 1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 Nh4 6.Qg1 Bd6 7.Rf2 Qd7 (2.211.059) 71
15.01 0:46 -0.75 1...Re4 2.Bxe4 Rxe4 3.Bd2 Qd7 4.Rf3 Nh4 5.Raf1 Qe6 6.Be1 Nxf3 7.Rxf3 Qg6 (3.225.000) 71
16.01 1:17 -0.75 1...Re4 2.Bxe4 Rxe4 3.Bd2 Qd7 4.Rf3 Nh4 5.Raf1 b5 6.R1f2 Nxf3 7.Rxf3 b4 8.Qg2 (5.420.370) 71
17.01 2:13 -0.75 1...Re4 2.Bxe4 Rxe4 3.Bd2 Qd7 4.Rf3 Nh4 5.Raf1 b5 6.R1f2 b4 7.Qe1 Nxf3 8.Rxf3 (9.362.273) 71

Rybka 2.3.2a

5.00 0:00 -0.12 1...Ng3+ 2.Nxg3 Bxg3 3.c4 (4.482) 41
5.00 0:00 -0.18 1...Nh4 2.Qg4 (5.084) 41
6.00 0:00 -0.16 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 (6.578) 42
7.00 0:00 -0.12 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Bd2 (9.348) 46
7.00 0:00 -0.13 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.bxc4 Nh4 (15.494) 50
8.00 0:00 -0.17 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.bxc4 Nh4 5.Bd2 (22.627) 49
9.00 0:00 -0.17 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.bxc4 Nh4 5.Rb1 c5 (38.919) 48
10.00 0:01 -0.17 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.bxc4 Nh4 5.Rb1 c5 6.d5 (74.631) 49
11.00 0:05 -0.16 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.bxc4 Nh4 5.Rb1 c5 6.d5 Qe5 (283.958) 56
12.01 0:10 -0.20 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.bxc4 c5 5.Rb1 cxd4 6.exd4 Nh4 7.d5 Re1 8.Bd2 (559.059) 57
13.01 0:19 -0.30 1...Ng3+ 2.Nxg3 Bxg3 3.c4 c5 4.cxd5 cxd4 5.e4 Rxe4 6.Bxe4 Rxe4 7.Qg2 Rh4 8.Rf3 (1.111.027) 59
13.02 0:22 -0.56 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxf4 6.Qxf5 Ne2 7.Bd2 (1.373.832) 62
14.01 0:25 -0.57 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxf4 6.Qxf5 Ne2 7.Bd2 Nxg1 8.Rxg1 (1.587.976) 62
15.01 0:31 -0.58 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxf4 6.Qxf5 Ne2 7.Bd2 Nxg1 8.Rxg1 (1.957.116) 63
16.01 0:41 -0.52 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxf4 6.Qxf5 Ne2 7.Bd2 Nxg1 8.Rxg1 (2.603.408) 63
17.01 1:03 -0.59 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxf4 6.Qxf5 Ne2 7.Rg2 Ng3+ 8.Rxg3 (4.019.183) 64

Hiarcs 12.0

9/22 0:00 -0.49 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 (152.454) 295
9/23 0:00 -0.29 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Bd2 Re6 5.Qh5 h6 6.c4 Rf8 7.Bb4 (168.048) 295
9/23 0:00 -0.30 1...Qc8 (170.675) 295
9/24 0:00 -0.34 1...Qc8 2.Bf5 Qb8 3.Bg4 Ng3+ 4.Nxg3 Bxg3 5.Rf3 Bc7 6.Ba3 Bd6 7.Bxd6 (189.800) 296
9/24 0:00 -0.35 1...c5 (262.392) 275
9/24 0:01 -0.35 1...c5 2.Qg4 Ng3+ 3.Nxg3 (294.255) 275
9/24 0:01 -0.35 1...Ng3+ (304.472) 275
9/25 0:01 -0.35 1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 (362.235) 274
9/25 0:01 -0.36 1...Re4 (473.946) 275
9/25 0:01 -0.36 1...Re4 2.Bxe4 Rxe4 3.Qf2 (493.167) 275
10/25 0:01 -0.11-- 1...Re4 2.Bxe4 (540.344) 272
10/29 0:02 -0.11 1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 (589.570) 275
10/29 0:02 -0.12 1...Ng3+ (596.852) 275
10/29 0:02 -0.12 1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 (654.458) 275
10/29 0:02 -0.13 1...c5 (703.397) 275
10/29 0:03 -0.13 1...c5 2.Qg4 Ng3+ 3.Nxg3 (813.183) 268
10/29 0:03 -0.14 1...Qc8 (830.572) 268
10/29 0:03 -0.44 1...Qc8 2.Bf5 Qb8 3.Bg4 Ng3+ 4.Nxg3 Bxg3 5.Rf3 Bd6 6.Qf2 c5 7.dxc5 Bxc5 8.Bd2 Qe5 9.Rf1 Qxg5 (881.531) 269
11/30 0:04 -0.37 1...Qc8 2.Bf5 Qb8 3.Bg4 Ng3+ 4.Nxg3 Bxg3 5.Rf3 Bd6 6.Qf2 c5 7.c3 b5 8.dxc5 (1.177.790) 274
12/32 0:09 -0.14 1...Qc8 2.Bf5 Qb8 3.Bd3 b5 4.Qg4 (2.527.860) 280
12/32 0:10 -0.15 1...Nh4 (2.960.872) 279
12/32 0:11 -0.49 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxe3 6.Bxe3 Nxf4 7.Qf3 Qe7 (3.278.801) 278
13/33 0:16 -0.61 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxe3 6.Bxe3 Nxf4 7.Bxf4 Rxf4 8.Qe2 Rxd4 9.Rg4 Rxg4 10.Qxg4 Be5 11.Rf1 (4.543.498) 281
14/34 0:25 -0.56 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxe3 6.Bxe3 Nxf4 7.Bxf4 Rxf4 8.Qe2 Re4 9.Qd3 Qe7 10.Raf1 Re2 11.Rg2 Rxg2 12.Kxg2 Qxg5+ 13.Kh1 Qh4 (7.211.307) 285
15/38 0:53 -0.66 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxe3 6.Bxe3 Nxf4 7.Bxf4 Rxf4 8.Qe2 Re4 9.Qd3 Qe7 10.Raf1 Re2 11.Rg2 Rxg2 12.Kxg2 Qxg5+ 13.Kh1 g6 14.Qf3 f5 (15.264.292) 284
16/39 1:40 -0.69 1...Nh4 2.Qg4 Re4 3.Bxe4 Rxe4 4.Nf4 Nf5 5.Rg1 Nxe3 6.Bxe3 Nxf4 7.Bxf4 Rxf4 8.Qe2 Re4 9.Qf3 Rxd4 10.Rg4 Rd2 11.Rg2 (28.210.392) 280

Zappa Mexico II

7/27 0:00 -0.43 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 dxc4 5.bxc4 (64.260) 242
7/27 0:00 -0.43 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 dxc4 5.bxc4 (89.964) 250
8/28 0:00 -0.32 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 dxc4 5.bxc4 (127.282) 254
8/28 0:00 -0.32 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 dxc4 5.bxc4 (217.324) 257
9/29 0:01 -0.35 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 dxc4 5.bxc4 (295.258) 262
9/29 0:01 -0.35 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 dxc4 5.bxc4 (399.309) 258
10/34 0:02 -0.43 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 Qd6 5.Rad1 c5 6.dxc5 (566.848) 268
10/34 0:02 -0.43 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 Qd6 5.Rad1 c5 6.dxc5 (742.217) 268
11/39 0:06 -0.44 1...Ng3+ 2.Nxg3 Bxg3 3.Qg2 Nh4 4.Qe2 c5 5.dxc5 Qxc5 6.Qg4 (1.776.751) 255
11/39 0:08 -0.44 1...Ng3+ 2.Nxg3 Bxg3 3.Qg2 Nh4 4.Qe2 c5 5.dxc5 Qxc5 6.Qg4 (2.166.790) 260
12/39 0:21 -0.50 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 Nh4 4.c4 Qd6 5.c5 Qc7 6.Rad1 Re6 (5.550.922) 255
12/43 0:43 -0.87 1...Nh4 2.Bd2 Bg3 3.Bf5 Nxf5 4.Rxf5 Qd7 5.Qf1 Qe6 6.Kg1 (11.228.413) 259
12/43 0:44 -0.87 1...Nh4 2.Bd2 Bg3 3.Bf5 Nxf5 4.Rxf5 Qd7 5.Qf1 Qe6 6.Kg1 (11.680.579) 260
13/43 0:58 -0.81 1...Nh4 2.Bd2 Bg3 3.Bf5 Nxf5 4.Rxf5 Qd7 5.Raf1 g6 6.Nxg3 Nxg3+ 7.Qxg3 gxf5 8.Qf4 Re4 9.Qxf5 Qxf5 10.Rxf5 (15.310.729) 262
13/43 1:02 -0.81 1...Nh4 2.Bd2 Bg3 3.Bf5 Nxf5 4.Rxf5 Qd7 5.Raf1 g6 6.Nxg3 Nxg3+ 7.Qxg3 gxf5 8.Qf4 Re4 9.Qxf5 Qxf5 10.Rxf5 (16.527.019) 264
14/43 1:18 -0.86 1...Nh4 2.Bd2 Bg3 3.Bf5 Nxf5 4.Rxf5 Qd7 5.Raf1 g6 6.Nxg3 Nxg3+ 7.Qxg3 gxf5 8.Qf4 Rc8 9.Qxf5 Qxf5 10.Rxf5 Kg7 (21.244.156) 269
14/43 1:24 -0.86 1...Nh4 2.Bd2 Bg3 3.Bf5 Nxf5 4.Rxf5 Qd7 5.Raf1 g6 6.Nxg3 Nxg3+ 7.Qxg3 gxf5 8.Qf4 Rc8 9.Qxf5 Qxf5 10.Rxf5 Kg7 (22.951.783) 271
15/47 2:05 -0.86 1...Nh4 2.Bd2 Bg3 3.Bf5 Nxf5 4.Rxf5 Qd7 5.Raf1 g6 6.Nxg3 Nxg3+ 7.Qxg3 gxf5 8.Qf4 Kg7 9.Kg2 Qe6 10.Kg3 f6 11.gxf6+ Qxf6 12.Qxf5 (34.385.957) 273

Shredder 11

1/04 0:00 +3.43 1...Bh2 2.Qxh2 (8) 0
1/06 0:00 +2.93 1...Nhf4 2.Nxf4 Nxf4 3.exf4 (28) 0
1/06 0:00 -0.77 1...Bb4 (46) 0
2/04 0:00 -0.51 1...Bb4 2.Qg4 (139) 0
2/07 0:00 -0.53 1...Ng3+ 2.Nxg3 Bxg3 3.Bd2 (272) 1
3/12 0:00 -0.61 1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bh4 (895) 4
3/12 0:00 -0.71 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 (1.565) 6
4/15 0:00 -0.50 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Bd2 a5 (3.679) 14
5/12 0:00 -0.29 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Bd2 g6 5.c4 (6.011) 22
5/14 0:00 -0.62 1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bd6 4.Qg4 Bb4 5.Kg2 (9.066) 32
6/23 0:00 -0.39 1...Ng3+ 2.Nxg3 Bxg3 3.c4 Nh4 4.cxd5 cxd5 5.Bd2 Qd6 6.Rac1 a6 7.a4 (51.295) 136
7/30 0:00 -0.26 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.Bxc4 Nh4 5.e4 b5 6.Bd3 Rxe4 7.Bxe4 Rxe4 (217.693) 296
8/23 0:01 -0.26 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.Bxc4 Nh4 5.e4 b5 6.Bd3 Rxe4 7.Bxe4 Rxe4 (359.534) 359
9/28 0:01 -0.07 1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.Bxc4 a5 5.Rf3 Bd6 6.Qg4 Bb4 7.a4 b6 8.Ra2 Qd6 9.Raf2 (805.029) 412
9/28 0:02 -0.11 1...Qc8 2.Bf5 Qb8 3.Qg4 Ng3+ 4.Nxg3 Bxg3 5.c4 Qd6 6.Bd3 dxc4 7.bxc4 c5 8.Bd2 Bh2 9.d5 (1.052.512) 429
10/28 0:03 -0.15 1...Qc8 2.Bf5 Qb8 3.Qg4 Ng3+ 4.Nxg3 Bxg3 5.c4 Qd6 6.Bd3 Nh4 7.a4 (1.379.267) 439
11/29 0:04 -0.06 1...Qc8 2.Bf5 Qb8 3.Qg4 Ng3+ 4.Nxg3 Bxg3 5.c4 Qd6 6.Bd3 dxc4 7.bxc4 Rd8 8.Rf3 Be1 9.c5 Qc7 10.Rb1 (1.967.383) 464
12/39 0:11 0.00 1...Qc8 2.Bf5 Qc7 3.Bd3 (5.885.480) 505
12/40 0:27 -0.25 1...Ng3+ 2.Nxg3 Bxg3 3.c4 c5 4.Rb1 cxd4 5.exd4 Re1 6.Bd2 Rxb1 7.Rxb1 Bf4 8.Re1 Rxe1 9.Bxe1 dxc4 10.Bxc4 Qc6+ 11.d5 Qd7 12.Qg2 Qe7 13.Bd2 (13.776.100) 500
13/35 0:31 -0.32 1...Ng3+ 2.Nxg3 Bxg3 3.c4 c5 4.Rb1 cxd4 5.exd4 Re1 6.Bd2 Rxb1 7.Rxb1 Bf4 8.Bxf4 Nxf4 9.Qg3 dxc4 10.bxc4 Re7 11.Rf1 Nxd3 12.Qxd3 Qa5 13.d5 (16.028.970) 506
14/40 1:05 -0.01 1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bd6 4.Qf2 a6 5.c4 c5 6.Bd2 Qc6 7.Rf1 dxc4 8.bxc4 b5 9.d5 Qb7 10.Bc3 b4 11.Ba1 Ne5 12.Qb2 (32.614.852) 495
14/42 1:19 -0.16 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Rg1 Bf2 5.Rf1 Qg3 6.Qxg3 Bxg3 7.c4 Rxe3 8.Bxe3 Rxe3 9.Bf5 dxc4 10.Bc8 Nf3 11.Bxb7 Nxd4 12.Kg2 cxb3 13.axb3 Bh4 14.Ra4 (40.236.449) 507
15/37 1:38 -0.27 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Rg1 Bf2 5.Rf1 Qg3 6.Qxg3 Bxg3 7.c4 Rxe3 8.Bxe3 Rxe3 9.Bf5 dxc4 10.bxc4 Nf3 11.d5 Nxg5 12.Rab1 cxd5 13.cxd5 g6 14.Bd7 b6 (51.478.045) 520
16/41 1:58 -0.09 1...Nh4 2.Qg4 Ng3+ 3.Nxg3 Bxg3 4.Rg1 Bf2 5.Rf1 Qg3 6.Qxg3 Bxg3 7.c4 Rxe3 8.Bxe3 Rxe3 9.Bf5 dxc4 10.bxc4 Nf3 11.d5 Nd2 12.Rfc1 Re5 13.Bc8 cxd5 14.cxd5 Rxd5 (63.093.581) 533

kgburcham · Post by **kgburcham** » Fri May 02, 2008 2:42 am

[D] 4r1k1/ppq1rppp/2pb2n1/3p2Pn/3P4/1P1BP2P/P1P1N3/R1B2RQK b - - 0 1

Deep Hiarcs 12:

1...Ng3+ 2.Nxg3 Bxg3 3.c4 dxc4 4.Bxc4 b5
=/+ (-0.48) Depth: 11/31 00:00:02 2685kN
1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bd6
=/+ (-0.50) Depth: 12/36 00:00:03 4350kN
1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bd6 4.Qg4 Qa5 5.Rf1 c5 6.dxc5 Bxc5 7.Qh5 Qc3 8.Rb1 Qe5 9.Rf3 Bd6 10.Rf4 f5
=/+ (-0.55) Depth: 13/36 00:00:06 8188kN
1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bd6 4.Qg4 c5 5.Bd2 c4 6.bxc4
=/+ (-0.42) Depth: 14/37 00:00:09 12731kN
1...Ng3+ 2.Nxg3 Bxg3 3.Rf3 Bd6 4.Qf2 Re4 5.Bd2 Nh4 6.Bxe4 Rxe4 7.c4 Qd7
=/+ (-0.37) Depth: 15/39 00:00:18 25121kN
1...Nh4
=/+ (-0.38) Depth: 15/39 00:00:20 28360kN
1...Nh4 2.Qg4 Re4 3.Bxe4
=/+ (-0.38) Depth: 15/39 00:00:22 30037kN
1...Re4
=/+ (-0.38) Depth: 15/39 00:00:26 35686kN
1...Re4
=/+ (-0.67) Depth: 15/39 00:00:28 38871kN
1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg1
=/+ (-0.67) Depth: 15/45 00:00:30 41750kN
1...Re4 2.Bxe4 Rxe4 3.Qf2 Ng3+ 4.Nxg3 Bxg3 5.Qg2 Nh4
-/+ (-0.84) Depth: 16/45 00:00:36 50659kN
1...Re4 2.Bxe4 Rxe4 3.Qf2 Qd7 4.Qf5 Qe8 5.Rg1 Nh4 6.Qf1 Qe6 7.Bd2 a6 8.c3 Nf5 9.Qf3 Nfg3+ 10.Kg2 Nxe2 11.Qxh5 Nxg1 12.Rxg1
-/+ (-0.97) Depth: 17/45 00:00:59 83291kN
1...Re4 2.Qf2 Qd7 3.Qf5 Qxf5 4.Rxf5 R4e6 5.Kg1 Nh4 6.Rf1 Rxe3 7.Bxe3 Rxe3 8.Rf2 Ng3 9.Re1 b6 10.a4 Nf3+ 11.Rxf3
-/+ (-0.97) Depth: 18/45 00:03:05 252mN
1...Re4 2.Qf2 Qd7 3.Qf5 Qxf5 4.Rxf5 Rxe3 5.Bxe3 Rxe3 6.Rf2 Nh4 7.Kg1 Ng3 8.Re1 b6 9.a4 Nf3+ 10.Rxf3 Rxf3 11.Nc1
-/+ (-1.20) Depth: 19/47 00:04:49 390mN
1...Re4 2.Qf2 Qd7 3.Qf5 Qxf5 4.Rxf5 Rxe3 5.Bxe3 Rxe3 6.Rf2 Nh4 7.Kg1 Ng3 8.Re1 Ne4 9.Bxe4
-/+ (-1.20) Depth: 20/48 00:06:51 554mN
1...Re4 2.Bxe4 Rxe4
-+ (-1.45) Depth: 21/52 00:13:21 1089mN
1...Re4 2.Bxe4 Rxe4 3.Bd2 Nh4 4.Nf4 Qd7 5.Qg4 Qxg4 6.hxg4 Ng3+ 7.Kg1 Nxf1 8.Rxf1 Be7 9.Kh2 Bxg5 10.Kg3 Ng6 11.Ng2 h6 12.Kf3
-+ (-1.43) Depth: 22/53 00:29:14 2425mN

Eelco de Groot · Post by **Eelco de Groot** » Fri May 02, 2008 3:55 am

These are the three best moves from Naum 3.1:

4r1k1/ppq1rppp/2pb2n1/3p2Pn/3P4/1P1BP2P/P1P1N3/R1B2RQK b - -

Engine: Naum 3.1 Settings (256 MB)
by Aleksandar Naumov

22 56:57 +1.34 23...Re4 24.Bxe4 Rxe4 25.Bd2 Nh4
26.Nf4 Qd7 27.Qg4 Qxg4 28.hxg4 Ng3+
29.Kg1 Nxf1 30.Rxf1 Bxf4 31.exf4 Re2
32.Bb4 Rg2+ 33.Kh1 Rxc2 34.a3 (3.527.114.609) 1032

22 61:09 +0.69 23...Nh4 24.Qg4 Re4 25.Bxe4 Rxe4
26.Nf4 Nf5 27.Rg1 Nxf4 28.Qxf5 Ne2
29.Bd2 Nxg1 30.Rxg1 Rh4 31.Qf3 Qd7
32.Kg2 Qe6 33.Rf1 g6 34.Be1 (3.800.868.522) 1035

22 80:21 +0.38 23...Ng3+ 24.Nxg3 Bxg3 25.Bd2 Nh4
26.Rad1 c5 27.Bc1 cxd4 28.exd4 Re6
29.Bb5 Rf8 30.Bd2 f6 31.gxf6 Rexf6
32.Rxf6 Rxf6 33.Rf1 Rxf1 34.Bxf1 (4.884.969.397) 1013

23... Re4 has a climbing score so it looks like Black might be winning no matter what White would respond.

I like that there is now a picture of you Tord! With the chosen resolution, which literally is too modest, it is not so clear, and the scene is also a bit dark, probably no flash used in the evening or maybe it is just my monitor, but now we finally can know which of the participants in Lodz was you! There was one picture of a Mac with Glaurung there but the operator was missing from the scene, and you did not point out yourself in the other scenes.

Eelco

michiguel · Post by **michiguel** » Fri May 02, 2008 7:45 am

Tord Romstad wrote:A curious fact about the new Glaurung is that it loves to sacrifice the exchange. I don't know why; I haven't changed the material values or anything else that should affect the program's willingness to part with an exchange. Whatever the reason is, I now see Glaurung make unclear or dubious exchange sacrifices all the time.

The following one looked so strange at first that I thought I had a bug:

[D]4r1k1/ppq1rppp/2pb2n1/3p2Pn/3P4/1P1BP2P/P1P1N3/R1B2RQK b - -

Glaurung (black) surprised me by playing 23... Re4!? This was almost certainly played as a positional sacrifice. The game was played at a time control of two minutes per game, with one second increment, on a single core of a 2.8 GHz Core Duo CPU. I doubt that Glaurung would see any very deep tactics at such a fast time control.

Do any other engines like Re4 here? Is it really a strong move? If it is, is it possible to explain the point of the sacrifice in terms an average human player can understand, without giving a ton of variations?

If I recall correctly, Glaurung's score at this stage of the game was about +1.5. Glaurung went on to win quite quickly and convincingly, but perhaps because of mistakes by the opponent. The full game:
Code: Select all
&#91;Event "Computer chess game"&#93;
&#91;Site "cm-84.215.94.43.getinternet.no"&#93;
&#91;Date "2008.05.02"&#93;
&#91;Round "2"&#93;
&#91;White "Toga II 1.4.1SE"&#93;
&#91;Black "Glaurung 080502"&#93;
&#91;Result "0-1"&#93;
&#91;TimeControl "120+1"&#93;

1. f4 d5 2. Nf3 Nf6 3. b3 Bg4 4. e3 e6 5. Bb5+ Nbd7 6. O-O c6 7. Be2 Rc8 8.
Bb2 Be7 9. h3 Bxf3 10. Bxf3 O-O 11. Nc3 Re8 12. Qe1 e5 13. fxe5 Nxe5 14.
Be2 Bd6 15. Qf2 Qc7 16. Kh1 Ng6 17. g4 Be5 18. d4 Bg3 19. Qg1 Bd6 20. Bd3
Re7 21. g5 Nh5 22. Ne2 Rce8 23. Bc1 Re4 24. Bxe4 Rxe4 25. Qf2 Qd7 26. Qf5
Qe8 27. Qf2 Nh4 28. Kg1 Qe7 29. Bd2 Qxg5+ 30. Kh1 Qg6 31. Rg1 Qe6 32. Qf1
Nf5 33. Qf3 Nfg3+ 34. Kg2 Rh4 35. Nxg3 Nxg3 36. Raf1 Qxh3+ 37. Kf2 Ne4+ 38.
Ke1 Qxf3 39. Rxf3 Rh2 40. Ba5 b6 41. Bc3 Rxc2 42. Kd1 Rxc3 43. Rg2 h5 44.
Rh3 Bf4 45. Re2 g5 46. Rf3 Kg7 47. Rh3 g4 48. Rxh5
&#123;White resigns&#125; 0-1
Tord

Congratulations Tord, you should be proud of your engine. This is fantastic move. With that move, blacks make sure that both knights will be posted in h4 and h5. They are devastating. Look at all the squares that they control. The rook in e4 supports h4 and g4, to make sure that the Q do not expelled them. Pawns in h3 and g5 are doomed. White position is locked and hopeless.

After few moves, this position is reached.

[D]4q1k1/pp3ppp/2pb4/3p2Pn/3Pr2n/1P2P2P/P1P1NQ2/R1B2RK1 b - - 7 11

Please check this position with your engine at a longer time.

Here, Glaurung played Qe7. I was analyzing with Gaviota playing back and forth as advanced chess and I think that Qe6!! is a knock-out. White can't avoid Rg4+!! without massive losses. For instance, Bd2 Rg4+/ hxg4 Qxg4+/ Ng3 f6! (to stop Qxf7+) and the white position falls apart despite the material disadvantage and white's turn.

[D]6k1/pp4pp/2pb1p2/3p2Pn/3P2qn/1P2P1N1/P1PB1Q2/R4RK1 w - - 0 18

Regards,
Miguel

Tord Romstad · Post by **Tord Romstad** » Fri May 02, 2008 8:02 am

Eelco de Groot wrote:I like that there is now a picture of you Tord! With the chosen resolution, which literally is too modest, it is not so clear, and the scene is also a bit dark,

The resolution is not too modest, I just appear to be one of the few people who actually try to follow the rules. The picture is not allowed to be wider than 80 pixels, and no bigger than 6 KB. My picture is exactly 80 pixels wide, and only 44 bytes below the 6 KB limit.

The original picture is actually not that bad, but I had to set the JPG compression settings very high and thus reduce the quality considerably in order to get below 6 KB.

probably no flash used

Flash was certainly used. I can even see some red color in my eyes in the full-size picture.

in the evening

Yes, in a certain sense. In Norway, we have perpetual evening/night approximately between November and March.

Tord

Tord Romstad · Post by **Tord Romstad** » Fri May 02, 2008 8:08 am

michiguel wrote:Congratulations Tord, you should be proud of your engine.

Thanks! Now that I have slept a few hours, Re4 no longer looks quite that strange. Black gets rid of white's only active piece, and gets able to bring the remaining rook into the attack. With all black pieces participating in the attack, and white having an exposed king and passively placed pieces, it must be an easy win. The other replies in this thread make it look like most engines actually like Re4.

After few moves, this position is reached.

[D]4q1k1/pp3ppp/2pb4/3p2Pn/3Pr2n/1P2P2P/P1P1NQ2/R1B2RK1 b - - 7 11

Please check this position with your engine at a longer time.

Here, Glaurung played Qe7. I was analyzing with Gaviota playing back and forth as advanced chess and I think that Qe6!! is a knock-out. White can't avoid Rg4+!! without massive losses.

Yes, Qe6 looks strong. I'll let my engine analyse the position when I get the chance. Right now, Glaurung is busy battling Hiarcs.

Tord

Tord Romstad · Post by **Tord Romstad** » Fri May 02, 2008 8:25 am

Terry McCracken wrote:Tord, where can I download this latest version you're using here?

The question is not where, but when. The answer is "some time really soon now".

Tord

CThinker · Post by **CThinker** » Fri May 02, 2008 7:34 pm

Thinker picks that move in less than 3 seconds. With the white king that exposed, it looks like the game is almost lost anyway.

Cheers!

Code: Select all

c&#58;\Temp\Thinker51D>"&#40;Passive&#41; Thinker 64-bit.exe"
Thinker&#58; 5.1D &#40;NA 046, 5dc, for 64-bit architecture&#41; Copyright &#40;c&#41; Lance Perkins

Thinker&#58; aet ueh
Thinker&#58; Freeware. No warranties whatsoever.
post
setboard 4r1k1/ppq1rppp/2pb2n1/3p2Pn/3P4/1P1BP2P/P1P1N3/R1B2RQK b - -
st 3
go
move e7e4
12 46 269 2998747 e7e4  c1d2  g6e5  d3e4
quit

Exchange sac

Exchange sac

Re: Exchange sac

Re: Exchange sac

Deep Hiarcs 12, 4 threads

Re: Exchange sac

Re: Exchange sac

Re: Exchange sac

Re: Exchange sac

Re: Exchange sac

Re: Exchange sac