Author: Mike S.
Date: 07:46:19 07/14/02
Go up one level in this thread
On July 13, 2002 at 18:05:38, Robert Hyatt wrote:
>(...) But the right circumstance
>must be hit... ie the capture opens the h file. The computer has castled
>and the opponent has not. There must be rooks and a queen still on the board.
>
>If all that is true, I doubt I would _ever_ make the capture unless I can
>in the same variation force the trade of queens or get rid of the rooks...
I'd be interested what you think about the common Lxh7+ sacrifice in the French
opening. Sometimes I was able to win against programs with that (slow comps
compared to now though), because they castled to the kingside, which surely was
the major mistake in those positions.
Note, that in both example games below, the white bishop was not yet on d3 when
Black castled.
And: In the popular set of Nunn Opening Positions, no. 3 is about the Lxh7+ sac,
where Black should avoid the castling move too. Ny impression is though, that in
many test games from Nunn matches, the result in that position often did not
depend on if Black castled or not (or if White played Lxh7+ or not then)... but
this would have to be researched further. I don't know if it's a forced win in
that position, after ...O-O.
[D]r3k2r/p1qbnppp/1pn1p3/2ppP3/P2P4/2PB1N2/2P2PPP/R1BQ1RK1 b kq - 0 11
No. 3 from the Nunn Openings.
Is this a similar danger for programs like the trojan sac (a little less
dangerous probably), and does it require special code to avoid the dangerous
castling? Or do you think, "normal" calculation and king safety evaluation
should be enough nowadays, to prevent against that Lxh7+ sacrifice?
Thanks,
Mike Scheidl
P.S. The games:
[Event "60/15:00 P133"]
[Site "?"]
[Date "1998.??.??"]
[Round "?"]
[White "Scheidl, M."]
[Black "Comet_A.75"]
[Result "1-0"]
[ECO "C19"]
1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Ne7 7. Nf3 Bd7 8. a4
Qa5 9. Bd2 Nbc6 {end of book} 10. h4 cxd4 11. cxd4 Qc7 12. Rb1 O-O 13. Bd3 Rfc8
14. Bxh7+ Kxh7 15. Ng5+ Kg8 (15... Kg6 16. h5+ Kh6 17. Nxe6+) 16. Qh5 Ng6 17.
Qh7+ Kf8 18. Rh3 b6 19. Rf3 Ngxe5 (19... Be8 $2 20. Nxe6+) 20. dxe5 Qxe5+ 21.
Kf1 Nd8 22. Bb4+ Rc5 23. Bxc5+ bxc5 24. Re1 (24. Nxf7 $1 {Fritz5} 24... Nxf7
25. Qh8+ Ke7 26. Qxa8) 24... Qb8 25. Qh8+ Ke7 26. Qxg7 Be8 27. h5 Qc8 28. h6
Qa6+ 1-0
[Event "60/30:00 P133"]
[Site "?"]
[Date "1998.??.??"]
[Round "?"]
[White "Scheidl, M."]
[Black "Diogenes 2.30"]
[Result "1-0"]
[ECO "C19"]
1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Ne7 7. Nf3 Qa5 8. Bd2
Nbc6 9. h4 O-O 10. Bd3 c4 (10... h6 {Fritz5} 11. Ng5 c4 12. Bh7+ Kh8 13. Qh5
Qa4 14. Rh3 Nd8 15. Rf3 Qd7 16. Rf6 $1 Ng8 17. Bxg8 Kxg8 18. Ne4 dxe4 19. Bxh6
g6 20. Qg5 Re8 21. h5 Qe7 22. hxg6 fxg6 23. Rxg6+ Kh8 24. Bg7+ Kg8 25. Bf6+ Kf7
26. Rg7+ Kf8 27. Bxe7+ Rxe7 28. Qxe7#) 11. Bxh7+ Kxh7 12. Ng5+ Kg8 13. Qh5 Rd8
14. Qxf7+ Kh8 15. Rh3 (15. h5 $1 Nf5 16. h6 Nxh6 17. Rxh6+ gxh6 18. Qh7#) 15...
Nf5 16. g4 Nxe5 17. dxe5 Qb6 18. gxf5 exf5 19. Qh5+ Qh6 20. Nf7+ Kg8 21. Nxh6+
gxh6 22. Bxh6 Kh7 23. Rg3 Rd6 24. Rg7+ Kh8 25. Qe8# 1-0
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