68 ( +1 | -1 ) Grunfeld refutation!?Ive been preparing for a tournament recently, and my main opponent, an IM, exclusively plays the Grunfeld. It would be risky trying to contest the main exchange line, but theres an alternative which i saw; d4 Nf6 c4 g6 Nc3 d5 cxd5 Nxd5 e4 Nxc3 bxc3 Bg7 Nf3 c5 Bb5+!? Bd7 (seems best)
and then Rb1 after which white has a very good game. Fritz 6 continues as the strongest Rb1 0-0 0-0 Bg4 Be2 after which Fritz gives white a 0.78 pawn advantage. The main idea seems simple enough with play along the queenside.
I would be grateful if anyone would like to share ideas in this line, maybe even further analysis witha stronger engine.
First of all, I hope you have an interesting game with the IM, manage to learn and have fun!
8.About Bb5+!?, according to stablished opening theory, it gives an = position
In my opening database I find that black's main moves after 11.Be2 are both 11...cxd4 (+=/=) and 11...Bxf3 (+=)
11... cxd4 12.cxd4 Bxf3 13.Bxf3 Axd4 14.Rxb7 Nc6 15.Qa4 Qd6 with a (+=) slight advantage for white evalutaion.
As you have Fritz (even if 6), maybe the best complementary computer analysis is then either Hiarcs or Rebel, both having a more accurate (knowledge based) analysis than Fritz (according to computer expert Amador Cuesta). Both these programs are more 'positional'.
I'll try to help with Rebel 12. That is a free computer program (beta version).
First, in the main tournament book for Rebel, it has Bxd7 instead of Rb1.
9.Bxd7 Nxd7 (or Qxd7) 10.O-O b5 11.a4 bxa4 12.Qxa4 O-O etc, which is another possibility.
But, back to your line
9.Rb1 O-O 10.O-O Bg4
candidates 11.Be3 11.Be2 11.h3
*Candidate 1: Be3 This move is the favorite of Rebel. 11.Be3 Qa5 12.Qa4 now 12... Qxa4 13.Bxa4 Nxf3 14.gxf3 cxd4 15.cxd4 gives too much advantage to white (1.03) 12... Qc7 13.Rfd1 Rd8 14.Be2 Nc6 15.h3 (0.47)
Main 'real' line (opening book) 11.Be3 cxd4 12.cxd4 a6 13.Be2 b5
Note about Rebel analysis: I did the analysis by having Rebel think for a long time the main move, and then went down the line, allowing rebel to reach depth 13 at least at every move. In some cases it changed the move in the main line, so I went down the new main line. Many moves have such a slight margin (0.34, 0.36, 0.37 between 3 candidates at move 13) that any of them is playable for the computer.
100 ( +1 | -1 ) Quick analysis9. Bb5+ was thought to be totally equal and drawn until Kramnik resurrected it a couple years ago and injected some new life--see the famous game Kramnik-Shirov.
The usual response for Black is 8... Nc6, which leads to a more or less equal position, although White may have some chances as in the Kramnik game. After 8... Bd7 9. Rb1, then 9... 0-0 10. 0-0 Bg4 11. Be2 cxd4 12. cxd4 Bxf3 13. Bxf3 Qxd4 14. Qxd4 Bxd4 15. Rxb7 led to a += to +/- position with good chances for White in Chekhov-Suhl, 1997(1-0, 52), but 10... Qc7 11. h3 Bxb5 12. Rxb5 b6 13. dxc5 Nd7 14. cxb6 axb6 15. Qb3 Nc5 was = in Skembris-Dorfman, 1992(1/2-1/2, 31); in Skembris-Tsheshovsky(1/2-1/2,22), White even saved a tempo on his earlier game, but failed to demonstrate any advantage after 10... Bxb5 11. Rxb5 b6 12. dxc5 Qc7 13. Be3 Nd7 14. Qb1 bxc5 15. Rd1 Qc6=. Fritz, or most other engines, don't evaluate the pawn sac correctly, so that's why they would show a large advantage for White.
Ultimately the line with 8. Bb5+ is an interesting sideline, as proven by Kramnik, but doesn't demonstrate any real advantage for White.