Wow! a very through post!

I have seen the ending of the 5....0-0 , Na6 line classified as better for white but I played it and found there was no advantage (things in fact were rather tricky)

On the Bf4 5...c5 lines I have found that present day juniors armed with their fritz + databases can make life hard for black where it is easy to find yourself fighting for the draw! There are many variations that are easy to get confused. 7.Qa4 lines, and on the 7.Rc1 dc4 lines I found it rather difficult to win as black!

Maybe these tactical openings are more vulnerable to general liquidation if opponent is well armed with Chessbase (Mega2006)  + fritz! than strategically complex ones

In this thread two seperate lines are discussed, which is somewhat confusing. Lets put together what we know
=========================================
First the bishop-sac line, or better a pawn-sac-line   :

1.d4,Nf6 2.c4,g6 3.Nc3,d5 4.Bf4,Bg7 5.e3,0-0 6.cxd Nxd5
7.Nxd5,Qxd5 8.Bxc7

Now black has three answers:
1) 8......Na6
2) 8......Nc6
3) 8......Bf5

1) 8...Na6 This is in fact the oldest variation of this line
(first played in Lowenfisch-Ragozin Leningrad 1936!!
White's most frequent answer has been 
9.Bxa6 when black has to decide if he wants to swap queens:

1x)  8...Na6 9.Bxa6, Qxg2 10.Qf3,Qxf3 11.Nxf3,bxa6
with a level endgame (Flohr-Botwinnik 1938).
1y) 8... Na6 9.Bxa6,bxa6 10.Nf3,Qb7 (10.Qf3,Qb5!)

2) 8....Nc6 Is the start of some rather speculative sacrifices. Whites best continuation is now Nge2 (the Knight is heading to c3 with tempo;
9.Nf3?,Bf5 =+):
8....Nc6 9. Nge2, Bg4 10.f3 And now black has two
possibilities:

2x) 10.f3,Bxf3 11.gxf3,Qf3 12.Rg1,Qxe3 13.Bf4
Bychovsky-Michalevski Ber-Sheeva 1996 as cited by Flear
Though white's task is maybe not so simple as it seems
(Timman-Pruissers, Amsterdam 2005: 0.5-0.5)

2y) 10.f3,Rc8 11.Nc3,Qe6 12.Bf4,Nxd4 is a much older line
with its own complications:
Lasker-Fine, New York 1940 (0-1)!.
It is interesting to note that Michalevski chose this line in 1997 against Volzin (0.5-0.5)

3) 8...Bf5 9.Nge2! is again fine for white
(not 9.Nf3,Nc6! and black gets enough counterplay)

========================================
The second line discussed in this thread is an exchange sacrifice, as made by Karpov against Kasparov in 1986.

1.d4,Nf6 2.c4,g6 3.Nc3,d5 4.Bf4,Bg7 5.e3,0-0 6.Nf3,c5
7.dxc,Qa5 8.Rc1,dxc 9.Bxc4,Qxc4 10.Bb3,Nc6 11.0-0,Qa5
12.h3,Bf5 13.Qe2,Ne4 14.Nd5,e5
Note that the position after move 11 can be reached by several different move-orders including 5...,c5.


15 Rxc6!
[ The first outing in this line went 15.Bh2 (Smejkal-Saidy 1971)]

15......., bxc6
[ Kasparov played 15....exf which should lead to a small white advantage]

16.Ne7+, Kh8

And now white has two options:
1) 17.Nxc6, Qb6 18.Nce5,Be6 19.Bxe6,Qe6 20.Qc2 =
(Gavrikov-Kochiev, Tallin 1987)

2) 17.Nxe5,Bxe5 18.Nc6,Qd2! 19.Qxd2,Nxd2 20.Be5+,f6
21. Bc3,Nxf1-+ Sokolov-Shirov, Wijk aan Zee 1999.

The Dreev games were part of the ICC databases since many of them were either simulcast by ICC or sponsored directly by the club.  You could also try TWIC (the week in chess at chesscenter.com) but I don't know which archives to look up.  The critical games occured about 2-3 years ago.   I don't remember exactly, but try the First Moscow Cup and see if he played there.  Good Luck!  I hope this helps.

Quote:


Hi ArKheiN

I tried to find the Karpov-Kasparov game, but found only 1 K-K 1986 with this line - and Kasparov responded to Rxc6 with 15...exf4, capturing the Bishop, not the rook! Were you thinking of a different game, and if so, could you give me a link/ref? The game in 1986 where Kasparov played 15...exf4 ended in a draw.

Fritz much prefers Rxc6 above retreating the Bishop, and 'thinks' the sac of the rook gives White good advantage (about half a pawn net).

If the better response for Black is to take the Bishop, as Kasparov obviously thought it was, then that looks like a good reason to play the rook sac as White if you get given the opportunity, as the good money would surely be on bxc6.

Has anybody got a reference to any of those Dreev games with 4Bf4?

Wow, Nge2!?  That's a new idea for me.   

I was used to playing Larsen's move order (Nf3 and Rc1 before playing e3)  But now I have something new to look at.  I never trusted any of White's attempts to win  material in this opening:  ....c5 before castling Bxb8? Rxb8 Qa4+ winning the a-pawn is known to be too dangerous.   

I'm joining the chorus that Black's best looks like Arkhein's line.  But I think White still has enough interesting play even in his critical position to be optimistic about scoring.  (Note, I didn't actually say White has a real advantage  )

15.Fh2 is a normal reply here, where Black reply with Rad8.
But in Karpov-Kasparov Wch :1986 Karpov played 15.Rxc6!? bxc6! 16.Ne7+ Kh8 17.Nxc6 Qb6 18.Ncxe5 Be6! where Nc4, Qc2 or Bxe6 have been played. I think Black have the better chances here.

Agreed - 5...c5 is the presently the most fundamental test of the 4 Bf4 variation.

Although Dreev seems to have lost interest in 4.Bf4 for the time being, notably Nakamura has been using this line to good effect recently (I think the game I saw in NIC Magazine was against Kudrin in the US Championship, however Kudrin avoided the most popular systems so perhaps Nakamura had prepared for the opponent rather than for the Grunfeld as a whole).

5...c5 is the main move these days rather than 5...0-0

Dreev used to play these Bf4 systems against the Grunfield al the time, but even he seems to given up on it. 

Perhaps you have some new ideas against 5...c5 !?

Andrew