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Old June 13th 04, 09:48 PM
Dr. David Kirkby
 
Posts: n/a
Default Was this offer of a sacrifice good or bad ???

I (g8wrb on ICC) just played a game as White which was drawn. At move
17, my bishop was attacked with 17...h6. I played 18. Bh4, knowing
that my opponent could trap the bishop after 18...g5. But I would have
played

19 Nxg5 hxg5 20. Bxg5

loosing me a knight, keeping the active bishop, and gaining two pawns,
leaving him with no f, g or h-pawns. I pondered for some time whether
this was a good idea or not, but eventually decided to let him trap
the bishop in return for the two pawns.

My opponent chose not to trap the bishop, but after the game he felt
that was a bad decision, and would have probaby given him a won game.
It was clearly something he too was a bit unsure about during the
game, but seemed to think it was his mistake.

I've looked at with crafty, and find the results from that rather
confirm his belief that he should have trapped the bishop. I'd be
interested in any comments on the game, but particulary at this point.

Overall, given the relative ratings of use two, I can be reasonably
pleased with the draw, but I wonder about this. There is a point later
in the game, where I could have played Rc1, which we both agree was a
mistake on my part. That might well have won me the game.

[Site "Internet Chess Club"]
[Date "2004.06.13"]
[Round "-"]
[White "g8wrb"]
[Black "karaybe"]
[Result "1/2-1/2"]
[ICCResult "Game drawn by mutual agreement"]
[WhiteElo "1354"]
[BlackElo "1566"]
[Opening "Konstantinopolsky opening"]
[ECO "C44"]
[NIC "KP.10"]
[Time "13:35:19"]
[TimeControl "2700+20"]

1. e4 e5 2. Nf3 Nc6 3. g3 g6 4. Bg2 Bg7 5. O-O d6 6. Nc3 Nf6 7. d3 Ne7
8.
Bg5 c6 9. d4 Nd7 10. Qd3 f6 11. Be3 O-O 12. Qc4+ Kh8 13. Rad1 Nb6 14.
Qb4 d5
15. dxe5 fxe5 16. Bg5 Re8 17. Rd2 h6 18. Bh4 d4 19. Rfd1 Qc7 20. Na4
Nxa4
21. Qxa4 Bg4 22. Bxe7 Rxe7 23. c3 b5 24. Qb4 a5 25. Qc5 dxc3 26. Qxc3
c5 27.
Rd5 Rc8 28. a3 Be6 29. R5d3 c4 30. R3d2 g5 31. Kf1 Bg4 32. Ke2 Rb8 33.
b4 a4
34. Rd5 Kh7 35. Rc5 Qa7 36. Kd2 Bxf3 37. Bxf3 Rd8+ 38. Kc2 Rxd1 39.
Bxd1 Qb6
40. Qe3 Qb7 41. Kc3 Rd7 42. Be2 {Game drawn by mutual agreement}
1/2-1/2


Dr. David Kirkby
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Old June 14th 04, 02:56 AM
Claus-Jürgen Heigl
 
Posts: n/a
Default Was this offer of a sacrifice good or bad ???

"Dr. David Kirkby" wrote:

I (g8wrb on ICC) just played a game as White which was drawn. At move
17, my bishop was attacked with 17...h6. I played 18. Bh4, knowing
that my opponent could trap the bishop after 18...g5. But I would have
played

19 Nxg5 hxg5 20. Bxg5

loosing me a knight, keeping the active bishop, and gaining two pawns,
leaving him with no f, g or h-pawns.


One alternative was 18. Bxe7, winning a pawn after 18...Qxe7
(18...Rxe7 19. Nh4 Kh7 20. Be4 Re6 21. Nxd5 Nxd5 22. Rxd5 with the
threat 23. Nxg6 Rxg6 24. Rd6 is much worse) 19. Qxe7 Rxe7 20. Nh4
(immediately 20. exd5 is possible but may be a bit complex after
20...Nc4) 20...Kh7 21. exd5. Now 21...Nc4 has lost its bite because
White controls e4 after 22. Re2.

Sacrificing a piece should be done only when you can come up with a
promising plan to follow. A general assessment without a plan is not
enough. Your pieces are not placed very well for a kingside attack. In
fact the white queen could be insecure. For example 18. Bh4 g5 19.
Nxg5 hxg5 20. Bxg5 d4 (Black threatens Ned5 trading the Bg5 against
the knight) 21. f4 (protects the Bg5 against Ned5 and attacks the
center) 21...Be6. Black threatens a5 and Nc4. It looks like White has
lost material and is on the defensive which is not a good combination.

A much more promising way to sacrifice a piece would have been 18.
cxd5, leaving the bishop en prise. This opens the diagonal for the Bg2
and the fourth rank for the queen. The white bishop or a knight can
now directed against the black king via e4 and the queen can switch to
the kingside at h4.

If 18...hxg5 19. dxc6 wins a pawn, attacks the queen and opens the
diagonal some more. 19...Qc7 (forced) 20. Nxg5 (threats 21. Nb5 and
21. cxb7 Bxb7 22. Qh4+ Kg8 23. Qh7+ Kf8 24. Ne6+) 20...bxc6 (what
else?) 21. Qh4+ Kg8 22. Rd3 (plans Rf3) and the situation for Black is
difficult, if not lost already. Note how the sacrifice opened files
and diagonals allowing White to build up threats quickly.

Black would be better off not to accept the piece. 18...cxd5 19. Qh4
Kh7 20. Re1 Qc7 21. Bxe7 Qxe7 22. Qxe7 Rxe7 23. Nxd5 leads to a
position similar to 18. Bxe7.

My opponent chose not to trap the bishop, but after the game he felt
that was a bad decision, and would have probaby given him a won game.


In hindsight Black didn't have to worry, as later the pin on the d1-h5
diagonal did give him several opportunities to win. Like 24...Rf7 and
how to defend the knight? 25. Rd3 c5 26. Qxb5 c4 wins. At best White
loses the exchange after 25. Nh4. Both sides overlooked this motif for
several moves.

It was clearly something he too was a bit unsure about during the
game, but seemed to think it was his mistake.
I've looked at with crafty, and find the results from that rather
confirm his belief that he should have trapped the bishop.


Just proving that humans are not as cold blooded as computers.

Some more comments:

1. e4 e5 2. Nf3 Nc6 3. g3 g6 4. Bg2 Bg7 5. O-O d6 6. Nc3 Nf6 7. d3 Ne7 8.
Bg5 c6 9. d4 Nd7 10. Qd3


In general, the queen is placed better on d2 in this kind of position.
White aims to trade off the Bg7 which protects the black kingside with
Bh6.

f6 11. Be3 O-O 12. Qc4+ Kh8 13. Rad1 Nb6 14. Qb4 d5


Opens the position when White is better developed.

15. dxe5 fxe5 16. Bg5


16. Bc5 makes the same threat but leaves g5 for the knight. For
example 16...Re8 (16...Bf6 17. Nxe5 oops!) 17. Ng5 (threat Nf7+, opens
the h1-a8 diagonal) 17...Kg8 18. exd5 wins a pawn. (18...cxd5 19. Bxe7
Qxe7 20. Qxe7 Rxe7 21. Nxd5; 18...Nexd5 19. Bxb6 Qxg5 20. Nxd5 (threat
Nc7) 20...cxd5 21. Bxd5+; 18...Nbxd5 19. Bxe7 Qxe7 20. Nxd5 cxd5 21.
Bxd5+)

Re8 17. Rd2


Losing time. Black can now close the center with d4 marking Rd2 as
useless. 17. exd5 with pressure against the black center on the d and
e-files should soon bring results.

h6 18. Bh4 d4 19. Rfd1 Qc7 20. Na4 Nxa4
21. Qxa4 Bg4 22. Bxe7 Rxe7 23. c3 b5 24. Qb4 a5 25. Qc5


Self trapping the queen. Black can win either a pawn or a piece for a
pawn. 25...Rf7 (threat Bf8) 26. d4 Rxf3 (or 26...Bxf3 27. Bxf3 Rxf3
28. dxe5 Qxe5) 27. h3 (27. Bxf3 Bxf3 28. Re1 exd4) 27...Rxf2 28. Kxf2
(or 28. hxg4 Rxd2 29. Rxd2 exd4) 28...Bxd1 29. Rxd1 exd4.

dxc3 26. Qxc3 c5
27. Rd5 Rc8 28. a3


28. Rc1 (that's what you meant?) 28...Rd7 29. Rxc5?? Qxc5 30. Qxc5
Rxc5 31. Rxc5 Rd1+ 32. Bf1 Bxf3 0-1.

Be6 29. R5d3 c4 30. R3d2 g5 31. Kf1 Bg4 32. Ke2


Self-pin, Black wins after 32...Rf7 (or Rf8) 33. h3 Bxf3 34. Bxf3 Rcf8
35. Bh1 (35. Rd5 Rxf3 36. Qxf3 Rxf3 37. Kxf3 c3 is hopeless as is 35.
Bg2 Rxf2+ 36. Ke1 Qf7 37. Rc2 Rxg2 38. Rxg2 Qf1+ 39. Kd2 Rd8+ 40. Ke3
Rxd1) 35...Rxf2+ 36. Ke1 Rf1+ 37. Ke2 R8f2+ 38. Ke3 Qb6+.

Rb8 33. b4 a4
34. Rd5 Kh7 35. Rc5 Qa7 36. Kd2


The king should go back to f1. Now 30...Rd8+ 31. Ke1 (31. Rd5 Qxf2+)
31...Rxd1 32. Kxd1 Rd7+ 33. Ke1 Rd3 with double attack on c3 and f3
wins.

Bxf3 37. Bxf3 Rd8+ 38. Kc2 Rxd1 39.

Bxd1 Qb6
40. Qe3 Qb7 41. Kc3 Rd7 42. Be2 {Game drawn by mutual agreement}

1/2-1/2

Claus-Juergen
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Old June 14th 04, 08:40 PM
Ray Gordon
 
Posts: n/a
Default Was this offer of a sacrifice good or bad ???

I think 3. g3 will stagnate you.

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"Dr. David Kirkby" m wrote
in message om...
I (g8wrb on ICC) just played a game as White which was drawn. At move
17, my bishop was attacked with 17...h6. I played 18. Bh4, knowing
that my opponent could trap the bishop after 18...g5. But I would have
played

19 Nxg5 hxg5 20. Bxg5

loosing me a knight, keeping the active bishop, and gaining two pawns,
leaving him with no f, g or h-pawns. I pondered for some time whether
this was a good idea or not, but eventually decided to let him trap
the bishop in return for the two pawns.

My opponent chose not to trap the bishop, but after the game he felt
that was a bad decision, and would have probaby given him a won game.
It was clearly something he too was a bit unsure about during the
game, but seemed to think it was his mistake.

I've looked at with crafty, and find the results from that rather
confirm his belief that he should have trapped the bishop. I'd be
interested in any comments on the game, but particulary at this point.

Overall, given the relative ratings of use two, I can be reasonably
pleased with the draw, but I wonder about this. There is a point later
in the game, where I could have played Rc1, which we both agree was a
mistake on my part. That might well have won me the game.

[Site "Internet Chess Club"]
[Date "2004.06.13"]
[Round "-"]
[White "g8wrb"]
[Black "karaybe"]
[Result "1/2-1/2"]
[ICCResult "Game drawn by mutual agreement"]
[WhiteElo "1354"]
[BlackElo "1566"]
[Opening "Konstantinopolsky opening"]
[ECO "C44"]
[NIC "KP.10"]
[Time "13:35:19"]
[TimeControl "2700+20"]

1. e4 e5 2. Nf3 Nc6 3. g3 g6 4. Bg2 Bg7 5. O-O d6 6. Nc3 Nf6 7. d3 Ne7
8.
Bg5 c6 9. d4 Nd7 10. Qd3 f6 11. Be3 O-O 12. Qc4+ Kh8 13. Rad1 Nb6 14.
Qb4 d5
15. dxe5 fxe5 16. Bg5 Re8 17. Rd2 h6 18. Bh4 d4 19. Rfd1 Qc7 20. Na4
Nxa4
21. Qxa4 Bg4 22. Bxe7 Rxe7 23. c3 b5 24. Qb4 a5 25. Qc5 dxc3 26. Qxc3
c5 27.
Rd5 Rc8 28. a3 Be6 29. R5d3 c4 30. R3d2 g5 31. Kf1 Bg4 32. Ke2 Rb8 33.
b4 a4
34. Rd5 Kh7 35. Rc5 Qa7 36. Kd2 Bxf3 37. Bxf3 Rd8+ 38. Kc2 Rxd1 39.
Bxd1 Qb6
40. Qe3 Qb7 41. Kc3 Rd7 42. Be2 {Game drawn by mutual agreement}
1/2-1/2


Dr. David Kirkby



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