Reply
 
LinkBack Thread Tools Display Modes
  #1   Report Post  
Old May 8th 04, 11:31 PM
Samik
 
Posts: n/a
Default N sac at f5 in clodsed Spanish: theoretical discussion

I wanted to know as much as possible about the possible
N sac at f5, in the closed Spanish. As we know, this
comes well into the middlegame, where white has Marshalled
his pieces towards Black's Kingside, and Black has played g6.
The sac at f5, followed by gf5, openes up the g file for
White's Kingside attack. People say this sac is quite normal, but
I have never succeeded with it against the computer. I have
tried various ways, (trying the sac early/as late as possible)
, but the computer always finds a defense.I am giving here
only one of those games. If somebody knows more about this
sacrifice and and attacking themes/tactical ideas, and wants
to share his/her knowledge, I will be most grateful.

[White "samik"]
[Black "gnuchessx"]
[Result "0-1"]
[TimeControl "40/300"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8.
c3 O-O 9. d4 Bg4 10. d5 Na5 11. Bc2 Nc4 12. h3 Bd7 13. b3 Nb6 14. Nbd2 c6
15. c4 Qc7 16. Bb2 bxc4 17. bxc4 Rfc8 18. Bb3 c5 19. Nf1 Rab8 20. Qe2 Na4
21. Bc1 Re8 22. g4 Rb7 23. Ng3 Reb8 24. Bd2 g6 25. Kh2 Nb6 26. Rg1 Qc8 27.
Bg5 Qf8 28. Qe3 Qe8 29. Nf5 gxf5 30. gxf5 Kh8 31. Bxf6+ Bxf6 32. Qh6 Qe7
33. Ng5 Bxg5 34. Rxg5 f6 35. Rg6 Rf8 36. Rag1 Be8 37. R6g4 a5 38. Rh4 a4
39. Bd1 Nxc4 40. Bh5 Bxh5 41. Qxh5 Rb2 42. Rhg4 Nd2 43. Rg6 Nxe4 44. h4
Nxf2 45. R1g2 e4 46. Qh6 Qe5+ 47. Kg1 Nh3+ 48. Kf1 Qxf5+ 49. Ke1 Rb1+ 50.
Kd2 Qxd5+ 51. Ke2 Qd3#
{Black mates} 0-1

Samik
  #2   Report Post  
Old May 12th 04, 12:01 AM
Ron
 
Posts: n/a
Default N sac at f5 in clodsed Spanish: theoretical discussion

In article ,
(Samik) wrote:

I know you wanted a theoretical discussion, but I think it makes more
sense to look at the practical example you provided. It's hard to talk
about tactics theoretically.

[White "samik"]
[Black "gnuchessx"]
[Result "0-1"]
[TimeControl "40/300"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8.
c3 O-O 9. d4 Bg4


As you probably know, it's usually a good idea to play h3 before d4
unless you want to play d5.

10. d5 Na5 11. Bc2 Nc4 12. h3 Bd7 13. b3 Nb6 14. Nbd2 c6
15. c4 Qc7 16. Bb2


I don't really like this move, as it's hard to imagine possibilities
that open the long diagnal up for you.

bxc4 17. bxc4 Rfc8 18. Bb3 c5


I hate this move as black. He's ganging up on the c-file. Why shut it
down? Your life just got a lot simpler.

19. Nf1 Rab8 20. Qe2 Na4


Don't like this, either. If he's going to now gang up on the b-file, he
should either play Ba4xb3 or a5-a4 to crack the file open.

21. Bc1 Re8 22. g4 Rb7 23. Ng3 Reb8 24. Bd2 g6 25. Kh2 Nb6 26. Rg1 Qc8 27.
Bg5


This strikes me as an inaccuracy. You're already planning to pry-open
the g-file, in which case this bishop is now just in the way. Instead,
Bh6! puts the bishop on a square where it can do a lot of damage: it's
easy to image tactics based on gxf5+, Bg7+, and Bxf6+. Notice how, on
h6, this bishop takes squares away from the black king! This is good if
you're planning an attack.

Qf8


Your attack has been slowed down.

28. Qe3 Qe8 29. Nf5 gxf5


Too hasty. Correct was Bh6 first.

Just for a moment, imagine your bishop was on h6. Now Nf5 isn't even a
piece sacrifice: Nf5 gxf Qg5+ mates.

There are plenty of other wins here if you miss that. It should be
trivially easy to see that you get the piece back with Bg7+ and Bxf6+
(even if you don't see that you can follow up with Qh6++).

The point is that if you get the bishop out of the way Nf5 is so strong
that black dare not accept it. (In which case, however, you need to find
a way to force black to accept it before you play it-- combine it with
other threats so that he has no choice but to grab it.)

30. gxf5 Kh8


A crucial tempo move.

31. Bxf6+


A ?? move which demonstrates the you don't understand that nature of
your attack.

Okay, I'm not going to claim to be able to find a win here for white
with best play, after a reasonable try from white like Bh6. Now I
wouldn't like to play the position as white against a computer, but
against a human of your abilities you certainly have some compensation
and might be able to keep things complex enough to win back your
material.

But the problem with this move is that in indicates, very clearly, that
you don't know what you're doing with your attack. Let me ask you a
simple question:

What squares are you attacking?

Looks to me like your best bet is to set up a focal point (see Vukovic,
"The Art of Attack") on g7. Your queen supported by a bishop or a rook.
Another posibility is regaining material via a discovered check Bg7+
Bmoves+. So you've got some tactical resources. But what do these
resources require?

First, that you have the pieces to use them. Second, that black is
unable to bring another piece to the defense of g7.

Let's list the things wrong with Bxf6+ -- because I think they're
educational.

1. It brings black's best defender of g7 to a square where it defends
g7.

2. It removes a crucial attacker that could be used to pry black's king
out of his hidey-hole.

3. It violates the general principle of not trading peices when behind
material. Trades, in general, help the defender.

4. It violates the general principle of not trading when you have more
space. Black's pieces are cramped, and this relieves them.

Now, it's true, black's bishop could have eventually defended g7 from
f8 anyway-- but of course now g8 can be a target, since it's no longer
protected by anything but the king.

After this move, your attack is dead in the water.

Bxf6 32. Qh6 Qe7
33. Ng5 Bxg5


I suspect you didn't see all the consequences of this move. The problem
is that even a weak play will probably find the correct defense here,
because you've got nothing more than a series of one-move threats. It
doesn't matter if you see ten one-move threats ahead, if your opponent
can defend against them one at a time, he will. Here you threaten his
bishop, so he defends it, you threaten mate with the knight, so he
swapts it off, and then:

34. Rxg5 f6


you threaten mate on g7, so he uncovers a defense of that square. Now
all his weak points are protected, and he can solidify his defense
(against the threat of Rag1) because you've got to move your other rook,
first.

35. Rg6 Rf8 36. Rag1 Be8 37. R6g4 a5 38. Rh4 a4


I'm not sure what you think Rh4 is accomplishing. In any event, the
position is now resignable.

39. Bd1 Nxc4 40. Bh5


Swapping off pieces helps the defender, but you had nothing at this
point anyway.

Bxh5 41. Qxh5 Rb2 42. Rhg4 Nd2 43. Rg6 Nxe4 44. h4
Nxf2 45. R1g2 e4 46. Qh6 Qe5+ 47. Kg1 Nh3+ 48. Kf1 Qxf5+ 49. Ke1 Rb1+ 50.
Kd2 Qxd5+ 51. Ke2 Qd3#
{Black mates} 0-1

  #3   Report Post  
Old May 13th 04, 05:53 PM
Mike Ogush
 
Posts: n/a
Default N sac at f5 in clodsed Spanish: theoretical discussion

On Tue, 11 May 2004 16:01:37 -0700, Ron
wrote:

In article ,
(Samik) wrote:

I know you wanted a theoretical discussion, but I think it makes more
sense to look at the practical example you provided. It's hard to talk
about tactics theoretically.

[White "samik"]
[Black "gnuchessx"]
[Result "0-1"]
[TimeControl "40/300"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8.
c3 O-O 9. d4 Bg4


As you probably know, it's usually a good idea to play h3 before d4
unless you want to play d5.

10. d5 Na5 11. Bc2 Nc4 12. h3 Bd7 13. b3 Nb6 14. Nbd2 c6
15. c4 Qc7 16. Bb2


I don't really like this move, as it's hard to imagine possibilities
that open the long diagnal up for you.

bxc4 17. bxc4 Rfc8 18. Bb3 c5


I hate this move as black. He's ganging up on the c-file. Why shut it
down? Your life just got a lot simpler.

19. Nf1 Rab8 20. Qe2 Na4


Don't like this, either. If he's going to now gang up on the b-file, he
should either play Ba4xb3 or a5-a4 to crack the file open.

21. Bc1 Re8 22. g4 Rb7 23. Ng3 Reb8 24. Bd2 g6 25. Kh2 Nb6 26. Rg1 Qc8 27.
Bg5


This strikes me as an inaccuracy. You're already planning to pry-open
the g-file, in which case this bishop is now just in the way. Instead,
Bh6! puts the bishop on a square where it can do a lot of damage: it's
easy to image tactics based on gxf5+, Bg7+, and Bxf6+. Notice how, on
h6, this bishop takes squares away from the black king! This is good if
you're planning an attack.


I created a database of the Spanish variation where black has played
g6 and white Nf5 to see if there were any patterns. One thing I
noticed is that in many of the games the move Nf5 is not a sacrifice
because either Black cannot take the knight with the g-pawn becasue
the pawn is pinned to the king or if Black can take with the g-pawn he
is mated or loses even more material than the knight he captured. In
quite a few of these positions the bishop is at h6, which contributes
the the mating threats as you point out.

However, in this particular game 27.Bh6 lets Black strike back with
27...Bxg4! and if 28.hxg4 (28.Nf5 Bxf5 29.exf5 Qxf5 is no better)
Nxg4+ 29.Kg2 Nxh6 and White has insufficent compensation for the two
pawn deficit.


Qf8


Your attack has been slowed down.

28. Qe3 Qe8 29. Nf5 gxf5


Too hasty. Correct was Bh6 first.

Just for a moment, imagine your bishop was on h6. Now Nf5 isn't even a
piece sacrifice: Nf5 gxf Qg5+ mates.

There are plenty of other wins here if you miss that. It should be
trivially easy to see that you get the piece back with Bg7+ and Bxf6+
(even if you don't see that you can follow up with Qh6++).

The point is that if you get the bishop out of the way Nf5 is so strong
that black dare not accept it. (In which case, however, you need to find
a way to force black to accept it before you play it-- combine it with
other threats so that he has no choice but to grab it.)

30. gxf5 Kh8


A crucial tempo move.

31. Bxf6+


A ?? move which demonstrates the you don't understand that nature of
your attack.

Okay, I'm not going to claim to be able to find a win here for white
with best play, after a reasonable try from white like Bh6. Now I
wouldn't like to play the position as white against a computer, but
against a human of your abilities you certainly have some compensation
and might be able to keep things complex enough to win back your
material.

But the problem with this move is that in indicates, very clearly, that
you don't know what you're doing with your attack. Let me ask you a
simple question:

What squares are you attacking?

Looks to me like your best bet is to set up a focal point (see Vukovic,
"The Art of Attack") on g7. Your queen supported by a bishop or a rook.
Another posibility is regaining material via a discovered check Bg7+
Bmoves+. So you've got some tactical resources. But what do these
resources require?

First, that you have the pieces to use them. Second, that black is
unable to bring another piece to the defense of g7.

Let's list the things wrong with Bxf6+ -- because I think they're
educational.

1. It brings black's best defender of g7 to a square where it defends
g7.

2. It removes a crucial attacker that could be used to pry black's king
out of his hidey-hole.

3. It violates the general principle of not trading peices when behind
material. Trades, in general, help the defender.

4. It violates the general principle of not trading when you have more
space. Black's pieces are cramped, and this relieves them.

Now, it's true, black's bishop could have eventually defended g7 from
f8 anyway-- but of course now g8 can be a target, since it's no longer
protected by anything but the king.

After this move, your attack is dead in the water.

Bxf6 32. Qh6 Qe7
33. Ng5 Bxg5


I suspect you didn't see all the consequences of this move. The problem
is that even a weak play will probably find the correct defense here,
because you've got nothing more than a series of one-move threats. It
doesn't matter if you see ten one-move threats ahead, if your opponent
can defend against them one at a time, he will. Here you threaten his
bishop, so he defends it, you threaten mate with the knight, so he
swapts it off, and then:

34. Rxg5 f6


you threaten mate on g7, so he uncovers a defense of that square. Now
all his weak points are protected, and he can solidify his defense
(against the threat of Rag1) because you've got to move your other rook,
first.

35. Rg6 Rf8 36. Rag1 Be8 37. R6g4 a5 38. Rh4 a4


I'm not sure what you think Rh4 is accomplishing. In any event, the
position is now resignable.

39. Bd1 Nxc4 40. Bh5


Swapping off pieces helps the defender, but you had nothing at this
point anyway.

Bxh5 41. Qxh5 Rb2 42. Rhg4 Nd2 43. Rg6 Nxe4 44. h4
Nxf2 45. R1g2 e4 46. Qh6 Qe5+ 47. Kg1 Nh3+ 48. Kf1 Qxf5+ 49. Ke1 Rb1+ 50.
Kd2 Qxd5+ 51. Ke2 Qd3#
{Black mates} 0-1


Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT +1. The time now is 07:15 PM.

Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2004-2019 ChessBanter.
The comments are property of their posters.
 

About Us

"It's about Chess"

 

Copyright © 2017