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Subject: For T. J. Frohlick: Taking up this position again with Tiger and Gambit

Author: Arturo Ochoa

Date: 10:55:25 10/08/00


Hello:

I'm building a specific Test Chess Suite based on the difficult strategic chess
theme of the pawn positional sacrifice.

This position, as I said previously, comes from one game of the 1999 Sarajevo
Tournament between Alexander Morozevich (2723) and Alexei Shirov (2726).
Alexander Morozevich sacrified a pawn spectacularly in the move forty. I am
really wondered how Morozevich found this move.

[D] 4r1k1/2pn1p2/1p3qp1/1P1Pb2p/2P4P/2B2BP1/2Q2PK1/3R4 w - -


According to Timothy J. Frohlick, Gambit Tigers got the position in only 2½
minutes.

He said : "Gambit Tiger 0.95 on a 333 PII with 24 Mb Hash finds the correct move
after 2 minutes and 30 seconds.  d6 cxd6 etc.  Not too shabby.  I think that
Gambit Tiger is a pretty strong program."

Source: http://www.icdchess.com/forums/1/message.shtml?131688

He says: "I guess that Gambit Tiger 0.95 is a wizard.  And I only have a PII
333Mhz 64M Ram machine".

Source: http://www.icdchess.com/forums/1/message.shtml?131689

I repeated the analysis process and my results were completely different from
the Timothy's ones.

For example:
Fritz6a only considers 40.Re1 after one hour of analysis.

Gambit Tiger only considers 40. Re1 after thirty eight minutes. Look:
0:0:38:30.8 1.52 18 1060611375 Re1 Re7 Bd2 Qd6 Qa4 Nc5 Qa8 Kg7 Qc6 f5 Re3 Rf7
Qxd6 cxd6 Ra3 Bd4 Bf4 Be5 Bg5.

As you can see, Gambit Tiger never consider the move 40. d6!! after 1 hour with
47 minutes.

However, Tiger 12.95b got the position in thirty minutes!
0:0:30:05.6 2.56 17 289975486 d6 cxd6 Bd2 Qe6 Bd5 Qg4 Bg5 Kg7 Re1 Rc8 Qa2 Qf5
Re3 f6
0:0:30:05.6 2.75 18 609564548 d6 cxd6 Bd2 Qe6 Bd5 Qg4 Bg5 Kg7 Re1 Rc8 Qa2 Qf5
Re3 f6 Rf3 Qg4

Tiger12.95 not only gots the correct move in thirty minutes, but also it keeps
this variation for a ply of 15 moves.

I used a PC with the following configuration:
PIII-600MHz.
Windows ME
CP5b.
I used 96Mb of Hash Tables for both Tiger12.95b and Gambit0.95b.

I have tested other Chess Programs, but the only one that got the move in that
position was Tiger 12.95b.

For my criterion, Tiger 12.95b "unbderstands" the position much better than
Gambit Tiger and others.

The complete .EPD line is:

4r1k1/2pn1p2/1p3qp1/1P1Pb2p/2P4P/2B2BP1/2Q2PK1/3R4 w - - bm d5d6;c0 Alexander
Morozevich (2723) - Alexei Shirov (2726);c1 Sarajevo  19.05.1999;eco C42;id Pawn
Positional Sacrificied  Pos 1;

The Complete Game is:

[Event "Sarajevo"]
[Site "?"]
[Date "1999.05.19"]
[Round "3"]
[White "Morozevich, Alexander"]
[Black "Shirov, Alexei"]
[Result "1-0"]
[ECO "C42"]
[WhiteElo "2723"]
[BlackElo "2726"]
[PlyCount "113"]
[EventDate "1999.05.17"]

1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6 7. O-O Be7 8. c4
Nb4 9. Be2 O-O 10. Nc3 Bf5 11. a3 Nxc3 12. bxc3 Nc6 13. cxd5 Qxd5 14. c4 Qd6
15. Be3 Bf6 16. Ra2 Rad8 17. d5 Na5 18. Nd4 Bd7 19. a4 Rfe8 20. Nb5 Bxb5 21.
axb5 b6 22. Bd2 Nb7 23. Rxa7 Nc5 24. Bf3 Be5 25. g3 Qf6 26. Kg2 Re7 27. h4 h6
28. Qc2 Rde8 29. Re1 Bd6 30. Rxe7 Qxe7 31. Qf5 g6 32. Qb1 h5 33. Bg5 Qe5 34. Ra3
Qd4 35. Qc2 Nd7 36. Rd3 Qa1 37. Rd1 Qe5 38. Bd2 Qf6 39. Bc3 Be5 40. d6 cxd6 41.
Bd2 Qe6 42. Bd5 Qg4 43. Bg5 Kg7 44. Re1 Rc8 45. Qa2 Qf5 46. Re3 f6 47. Rf3 Qg4
48. Bf4 Re8 49. Qa7 Re7 50. Qc7 Kh7 51. Bxe5 dxe5 52. Qd6 Rg7 53. Bc6 Qd4 54.
Rd3 Qxd6 55. Rxd6 Nc5 56. Rxf6 Ra7 57. Bd5 1-0

Alternative variations to the game main line would be:

1) If 40. ... Bxc3 41.dxc7 Nc5 42. Qxc3 Qxc3 43. Rd8
2)                 If 41...Ad4 42.Ab7 Ce5 42.Dxc3


Best Regards, Arturo Ochoa.



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