More on identifying "high level" games: you could also order on the minimum of the Elos of the two players.

Stefan my be mistaken about that particular position, but it doesn't really affect his advocacy of 2.a4, which mainly envisions some sort of closed Sicilian.

So l'd like to come back to that and 2...a6, which is a move I continue to like.  Since 2...a6 3.Nc3 Nc6 4.f4 e6 5.Nf3 d5 6.d3 Nf6 does not appear to be very good for White, I assume White's main idea would be 4.g3.  Against that, Black's set-up ...g6, ...Bg7, ...e6, ...Nge7 looks flexible and preserves ...d5 in one go as an option.  For example 4.g3 g6 5.Bg2 Bg7 6.d3 e6 7.f4 Nge7 8.Nf3 d5 9.O-O O-O.  This position has come up in 20 games in my database, White scoring 30.2%.  That score seems ridiculous to me, since I don't think White is worse, but I don't think that Black is worse either.  He has the obvious plan of ...Rb8, ...b5 and so forth. It looks like a game of chess where both sides have pretty significant winning chances, which is just what I like about Black's side of Closed Sicilian.

If White instead of 7.f4 goes with 7.Be3, then 7...d6 8.Qd2 Rb8 looks pretty interesting, and I see no reason why Black should be worse.  E.g. 10.Nge2 b5 11.axb5 axb5 12.0-0 b4 13.Nd1 Nd4 appears to be another one of those positions where both sides have good winning chances.

Stefan, you apparently understand these Closed Sicilian positions better than I do, since you've worked out a theory under which a4, ...a6 favors White.  So I look forward to being educated on this subject.  Why is White better after the methods that I've proposed for Black?

For what it's worth, I don't know that statistics are much of a guide to these positions with a4 and ...a6 in, since I've noticed that the games are mostly rather low-level.  However when the number of games goes up into the hundreds, I think the statistics do mean something. 

P.S. Moderator, maybe this 2.a4 Sicilian discussion should be snipped off and moved into Anti-Sicilians.

P.P.S. Stefan, ordering groups of games by White's average Elo introduces a bias, in that the stronger White is, the larger the likely disparity between White and Black.  To identify games as high-level, you should order by the average of both player's Elos.  Otherwise your results are contaminated by the tendency of stronger players to defeat weaker ones in the higher groups, and the symmetrical effect in the lower groups.

Stefan Buecker wrote on 08/17/11 at 00:09:19:


If we take this line one move further with 8...d6, we have the following position:



I can't imagine why you would prefer White.  Black has a standard Dragon position, while White has made a couple strange (and frankly just harmful) moves.  The b4 square is chronically weakened (in fact, White would prefer that the pawn be back on a2) and the queen stands awkwardly on d2.  Black looks slightly better to me.

Markovich wrote on 08/16/11 at 15:50:51:

First of all, thanks for all the constructive replies posted yesterday and today. I'll address more of it soon. 

Yes, 2...a6 should be seriously considered. The idea that the pair of moves a6/a4 was good for Black stems from the old times when the accepted way to counter the Closed Sicilian was Rb8 followed by b5 and b4. There were lines with a3, exchanging pawns on b4 (or maybe with a4 as a reaction to a5). A very similar thing may appear on the board after a6/a4 if Black continues with Rb8 and b5. Boris Spassky not only played these nice king-side attacks vs Portisch, he was also able to show that often White must play an active role on the queenside, in contrast to what was formerly believed. 

In http://www.chesspub.com/cgi-bin/yabb2/YaBB.pl?num=1309410160/5#5 I had discussed the line 1.e4 c5 2.Nc3 e6 3.g3 d5 4.exd5 exd5 5.Bg2 Nf6 6.d3 d4 7.Ne4 Nxe4, trying to explain why White scored badly here. (Yes, it is different than the version with a6/a4 included. But in both cases I believe that the position is objectively doing fine for White, at least in the hand of good players.)



Stefan Buecker wrote on 07/01/11 at 02:58:19:

I still feel that there must be lines in which the tempo used for 2.a4 could be better for something else, as TalJechin says about the center play e.g. Also, the weakening of b4 this early can't be better than the advantage of a4 when Black has played neither ...a6 nor ...b6, can it? Don't have any concrete lines though, without looking at it more in detail. Anyway, thanks for the link Stefan.

Stefan, I didn't see your link, sorry; but I also have not issued any sweeping condemnations or said that anyone's work shouldn't be published. My essential point was that analysis that commences at move two must necessarily be inadequate for determining moves at that stage and that, therefore, one must rely on principle. In all fairness, I don't think that that's an empty statement.

I agree that in chess, eventually, all is specificity. I do not agree that this means that chess principles aren't a good basis for finding moves in many situations. For humans finding them, at any rate.
 
Further, what is your argument about not opening the game early but an appeal to principle?

SWJediknight wrote on 08/15/11 at 17:56:59:

In some lines my article wasn't very specific. For example, after 2...a6 I just linked to another article on 2.Nc3 a6 3.a4. In my experience the pair of moves a6/a4 improves White's chances in the Closed Sicilian. The most popular Anti-Closed set-up today is the one with b6, Bb7, Qd7, f5. Softening up Black's structure on the queen side (b5 axb5 axb5) is a small success. Black can still play b6 after a4/a6, but the structure is weaker than without a7-a6. In opening books I've sometimes seen remarks that the inclusion of a4/a6 in the Closed Sicilian favoured Black, but in this point I disagree. 

Regarding the question whether a4 is useful in Bb5 Sicilians, Gerard Welling knows more about these positions than I do. He believes that it is useful in many lines, but not in all cases. However, he doesn't think that there is a single line where a4 is more a negative than a positive factor. And we shouldn't forget that a4, innocuous as it seems, produces a new situation, it isn't simply an English Opening Reversed. There are many people who do play 1.c4 e5 2.Nc3 Bb4 with Black and think it is equal. Ask them whether they'd like a move a5 for free!

Djy wrote on 08/15/11 at 13:08:30:

That comes close, but I think Gerard would rather say: it requires some good moves from Black, and if he finds a line where a4 isn't a real advantage, then let's play chess. 

SWJediknight wrote on 08/15/11 at 17:56:59:

Don't ask me about details (someone else did the work), but 6.Qe2 is equal at best. (And TalJechin's 2.Nc3 d5: I always loved that with Black. Sicilian 2.Nf3 advocates are lucky that e5 is unprotected.) I am a big fan of the Scotch, but 4.Nxd4 Qh4 is Black's best option and entirely unclear. 

@TalJechin: Thanks for your remarks. You mention 2...a6 and 2...g6. My article http://www.chesscafe.com/text/kaiss65.pdf already said a bit about these moves: 

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