Sorry for not replying to the recent posts, but I am quite busy now.
Perhaps this will start the discussion again:
Magnus Carlsen just played the "refuted" Benko gambit and beat Leif Erlend Johannessen in a tough fighting game! 

Here it is:

GM Leif Erlend Johannessen - GM Magnus Carlsen
Midnight Sun Chess Challenge (Tromsø), 06/27/2006
Round 4

1.d4 Sf6 2.c4  c5 3.d5 b5  4.cxb5 a6 5.bxa6  g6 6.Sc3 Lxa6  7.g3 d6 8.Lg2  Lg7 9.Sf3 Sbd7  10.Tb1 O-O 11.O-O Da5  12.Dc2 Tfb8  13.Td1 Sg4 14.Ld2  Sge5 15.Sxe5  Sxe5 16.b3 Lc8  17.Sa4 Da6 18.Lc3  Lf5 19.Le4 Ld7  20.f4 Sg4 21.Lxg7  Kxg7 22.Lf3  c4 23.e3 Da7  24.Te1 cxb3 25.axb3  Sf6 26.Ta1 Tb4  27.Kh1 Tc8 28.Dd1  Db7 29.e4 Txb3  30.e5 Sg4 31.Lxg4  Lxg4 32.Dxg4  Dxd5+ 33.Kg1  Tc2 34.Dh3 Dd4+  35.Kh1 Te3 36.Df1  Dd2 

0-1

Ametanoitos wrote on 05/05/06 at 16:17:46:

ok, that's right! I didn't analyse on the chessboard so I just overlooked that the Knight is hanging. sry!!

Ametanoitos wrote on 05/05/06 at 16:17:46:


WIth "pin" I didn't mean the pawn is pinned vecause of loosing a bishop, but because of getting exchanged the bishop! After 12. Nh4 e6 13. de6: Bg2: 14. Ng2: fe6: I don't think that White has a clear advantage, because now black has (after ... d5) a strong centre, the half-open f-file (lucky rook after castling) and the white kingside-fianchetto now has turned out as just moving the knight form the active f3-square to the passive g2-Square. Now White has a fianchettoed knight and weakened his kingside. So I think there's enough compensation for black! or do I overlook sth again?

regs

Ametanoitos wrote on 05/02/06 at 11:27:42:


after 12. e4 Ba6!? White can start an immediate attack with 13. e5! looks dangerous.
after 12. Nh4 the pin on the h1-a8-diagonal could be nasty: 12. ... e6! and if now 13. e4 ed5: 14. ed5: Ba6! is good (because the white knight isnt on f3 anymore)
All in all, good counterplay for Black
or did I miss sth??

regs
Jacky

After 1. d4 Nf6 2. c4 c5 3. d5 b5 4. cb5: a6 5. ba6: g6 6. Nc3 Ba6: 7. Nf3 d6 8. g3 Bg7 9. Bg2 Nbd7 10. Rb1
there is the idea 10. ... Nb6 11. b3 Bb7!? with pressure on the weak d5 pawn. After eg 12. e4 0-0 13. 0-0 e6! White has an unpleasant choice:
- allow Black to exchange on d5 and attack white's weak pawn  or
- play 14. de6: Ne4: 15. ef7:+ Rf7: when Black has a strong centre and attacking chances along the f-file.


What do you mean??

regs
Jacky

I also own Pinski's book and think that black is fine in the main variation.
But some months ago I had the chance to play the line in a 15min. rapid game with black against a GM.
He played 14.Bb2 (instead of 14.f4) and I continued with Bb7 15.0-0 0-0 16.e4 Rfc8 17.a3 c4 18.b4 Na4 19.Na4: Ra4: 20.Rfc1 c3! 21.Bc3: Ne4:? 22.Qe4: Bc3: 23.Ng6:! fg6: 24.Qg6: Bg7 25.Be4 and white had a very strong, probably irresistable attack.
But if I had played 21. ... Nd5:! instead of Ne4: white wouldn't have activated his queen and after 22.ed5:   
Rc3:! 23.Qe4 Raa3: black seems better.
So 14. ... Bb7 was my "novelty" I produced because I didn't know what Pinski wrote about the position.
What do you think of this variation? I somehow have the feeling that white could improve on the game's continuation and that he should be better, but I'm not sure how.   
In his book Pinski gives "14.Bb2?! g5 15.Nf3 Bb7 16.Nd2 0-0 gives black a good game because white must either lose the d5-pawn or leave the king in the centre".
But Gustafsson, Kasimdzhanov and Epishin have played Bb2, so I don't think that it is bad.
16.Rd1! also seems better than Nd2, after 16. ... 0-0 17.0-0 Nfd5: 18.Nd5: Nd5: 19.Bg7: Kg7: 20.Ng5:! white remains a pawn up. Does black have compensation here? At least Gustafsson won a game from this position with white.
Also interesting is 14.0-0 with similar ideas.
Against both moves, Bb2 and 0-0, van der Weide has played the manouver 14. ... g5 15.Nf3 Qf5!? 16.e4 Qg6.
It looks interesting, but I'm not sure if it is enough compensation.

By the way, funny that many players like both the Dragon and the Benko! 

Quote:


Pinski doesn't mention 11.b3 Ra7 but 11...0-0, 11...Bb7 and the critical line 11...Bc8! (intending Bf5 to provoke e4) 12.Nh4 h6 13.Qc2 Qd7 14.f4 Bb7 15.Bb2 0-0 16.Qd2 Rfe8 17.0-0 Ng4 18.Nf3 e6 19.dxe6 Qxe6 20.e4 f5 and black has good counterplay.

Ametanoitos:

The Epishin line is critical right now for the Benko (i.e. there won't be any magic bullets or quick fixes) but I would suggest looking at the lines with ...Qa5 and a very quick ...c4.   The Cao Sang game from last year is a good starting point.  Also, its worth noting that although white is slightly better in these lines it is very hard for white players to avoid having at least one pair of knights traded off and the ensueing endgame is not exactly "White to move and win".  I've faced 10.Rb1 several times but never lost (even gotten a couple of 0-1's).  A quick ...c4 seems to give most white players enough to worry about on the Queenside.

  Basically:  Relax, you don't need to give up any more material and you don't need to start to panic yet.
   
Hopefully a clear solution will be found and theory will show clear equality.  But until then , just play it as a typical Benko and understand while white has kept some of his opening advantage, black still has decent, traditional compensation and is only slightly worse.  Its far from decisive (especially at club level).