Sicilian San-Francisco Gambit

I don't know about this move for. Anyone can tell me the next move ?

well obviously black should accept the gambit

cb

accept the gambit with a6- after bxa5 axb5 there is no way to protect the pawn from Rxa5 and the rook has an open file

Yeah, I was wondering what the gag is, so I ran it through Stockfish (depth 20  approx) and it seems to quite like White's position and gave the following variation:

I personally find that position far from clear. Both c3 and c4 (possibly desirable central moves) of course run into ...bxc3 so for that (and taking away c3 from the knight) the b4 pawn is serving a good function. White certainly has a nice pawn chain but first off black's pieces hold their own (the knight on d5 and the a5 knight can go to c6 at some point) too, white's center can be attacked, and most importantly it doesn't look easy for white to generate an attack here right now, since black isn't castled. The knight on d5 makes development slightly annoying for white.

But the position is very interesting, and I am generally more biased towards material. In fact maybe a good idea for white in the long term (though I would castle first) is to just develop with Be3 and allow ...Nxe3, cause when the f file is opened then I'm starting to see some possible attack from white. But white always has to take ...d6 into account, where the bishop may not be ideally placed. So white's development is a bit more comfortable (but still a little awkward) and he's up in space but the position is closed (making any quick attacks very hard), black still seems to be able to get his pieces out with fianchettoes of the bishops and can also make white be careful about commiting to a k side attack with the threat of ...d6 later. I think if we were to find the truth of the position, more analysis would be required.

 I wouldn't go by solely computer analysis to find the evaluation of an opening line, though it is interesting that computers, often materialistic, like white's position. With that said, my fritz 10 says white is only slightly better in your position, and that b4 is a big mistake, yet white is still better (because ...Na5 is so bad). So what fritz is saying is that against such a bad move like ...Na5 there's no point in trying to play a risky gambit when you can have such a clear advantage by safer means ( in fact it thinks after 3...Na5 white is better by 1.27... I knew Na5 wasn't good, but wow).

Fritz recomends 8 Ng5!!

So does Stockfish... it's an interesting position with all manner of unlikely moves in the offing.

Although I play the Rossolimo, I have yet to encounter 3. .... Na5 (looks counter-intuitive to me) but if I do, I will be sorely tempted to play 4. b4!?

Looks pretty wild.

Yeah after that move, I can see why white would stand better. I just thought there was nothing so tactical white could immediately do, but I was wrong.

Why would amybody play Na5?

Moves a piece twice in the opening.

Threatens nothing.

Does nothing for development

Does nothing for king safety

Doesn't fight for the center.

Puts a knight on the rim.

I found 6 games of GM Kozul in this variation which he won all (admitely against lightly weaker opponents) so clearly Na5 has some point to it.

Fritz actually thinks black is borderline losing after ...Na5, and that b4 "keeps him in the game".

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