anderssen opening

1.a3.. 2.b4..

The idea of 1.a3 is not to play 2.b4 next.

Otherwise, what not playing 1.b4?

The idea is to play with black, with a3 inserted which can be useful in many variations.

Did Anderssen ever say why he played 1 a3.

A player might could use 1 a3 to narrow down theory substantially if he doesn't mind playing black always and can find a repertoire in which playing black with 1 a3 will be usually useful and at least not harmful. 

For instance, in playing 1...d6 with the intention of playing the Old Indian and the Modern Philidor ...a6 is often useful as black seeks to push ...b5 in many lines. If a player uses the Old Indian/Modern Philidor then by that same player going 1 a3 white is going to be a tempo up in that middlegame strategy, or at least probably not behind if the line turns out to be one in which 1 a3 was not helpful. 

I say "probably" not behind because I have not worked it out and there may indeed be lines in which one would wish the pawn was still sitting on a2, 1 a3 turning out to be harmful, and at other times the pawn might be better off at a4 (...a5 as black) so the move 1 a3 was not helpful but not harmful either.

I've had much interest in using the book titled Play 1...d6 Against Everything, and even though the book is intended as a black repertoire I've thought about how nice it would be if I could play 1 a3 and use the book really for everything.  It's a good book in that it doesn't just present a repertoire it also teaches the middlegame plans. However, I haven't worked out all the nuances, I'm still undecided if 1 a3 is worth it or not in playing this repertoire. 

In this day and age finding something sound that is off the beaten path is not easy, so many club players use off the path openings and defenses those openings and defenses can hardly even be considered off the beaten path anymore at the club level. 

But how many club players are willing to play the Old Indian and Modern Philidor, or even study those two defenses for when they face it. Not many. I think it might be an avenue for those seeking something different.  By playing it as white too one then has perhaps finally found a sound (though kinda passive) complete concise repertoire all in one 200 page book. 

the point of 1.a3 is to not need book and play a black defense with an extra, perhaps helpful tempo. 2.b4 is possible, especially vs 1.e5 which transposes to a sideline of 1.b4 for those that rather avoid bxb4 (sometimes, this is done to keep the position closed especially agaisnt prepared players or very tactical ones) but this move order really doesnt have much benefit.

i never understood the rationale  in playing black defenses a move up. Just like the English and the sicilian dont quite translate the extra-tempo advantage neatly, i dont think 1.a3 would make any "white defense" keep an advantage (even  actual equality i think would be slightly off the mark, a feather bit worse but comfortable is more probable).

But it has worked for a small number of people so if this is your version of the beaten path, more power to you.

I bet 1. a3 is better than the Orangutan/Sokolsky.

1. b4 simply over-exposes white.

After 1. b4 it is 0.0 at worse for black, so fully equal.

I bet 1. a3 might end up with a very small plus for white, somewhere in the range 0.02-0.05

So, Anderssen was wiser than the Orangutan.

Almost certainly, 1. a3 is better than 1. h3 too, so not that bad at all.

U should be surprised how black face problems after these twin lines in 4 knights game :

a3/h3 are useful, and not so easy for black to find the good way (if there is!).

can recommend a reversed Qd6 scandi with a3 not easy for black

Right, I often play various reversed variations in this way and using reversed databases. 

I've used 1. a3 quite often as a change-of-pace opening, and also to pressure those opponents which I do better as black against (of which I've encountered a few).  It is especially effective against those who play the 1. e4 as white, as virtually all of those openings rely on the threat of putting a minor piece on b5 at some point.  Therefore, it is generally more effective against those who respond with 1. ..e5 than those who respond with 1. ..d5, and also good against 1. ..Nf6 and 1. ..Nc6.

Anderssen basically used it as an anti-system for the king's pawn opening against Morphy (and scored 50% with it).  1. a3 may seem like a minor wrinkle in the King's pawn game, but it is actually quite substantial.

i had played a whole tournament with the move  a3 and defeated ratedes  LOL they were looking at their friends and laughing

a3  is sometimes good because some players learn only few opening and lines. but they never expected the move a3. then u can easily play positional and tactical with ur own choice. nothing more to say.

But don't be mistaken.

In my opinion, 1.a3 is very theorical on the contrary!

White will try to obtain theorical position with a3 useful.

Up to black to find where a3 is not so useful.

That's why for instance 1.a3 g6 is often given, because a3 pretty useless here : not completely but less than 1.a3 e5 and 1.a3 d5.

@poucin - I've seen 1. a3 g6 played against me a few times when I've opened with Anderssen (against opponents rated in the 1600-2000 range), to which I usually reply 2. Nf3 (setting up for 3. d4), or else I play 1. d4 immediately.  In either case, I've gotten good results against it.

To reply with 1. ..g6 seems both passive and committal, so the fianchetto is blunted on the long diagonal by a white pawn on d4 or (if white doesn't set up for d4) by a black pawn on e5.  If the game proceeds to a King's Indian Attack with the colors reversed (as seems likely), then 1. a3 is a useful tempo for a queenside pawn storm, which is common to such games (at least in my own experience).

I think it's a mistake, at least strategically, to try and make the a3 push useless - it is what it is, and it should be taken as-is.  Why would you revert to an opening which with white is otherwise regarded as inferior just to avoid letting a3 be useful?  For instance, you could continue on 1. a3 g6 with 2. e4 f5 3. exf5 gxf5 4. Qh5# (extreme example, but you get the point), and 1. a3 proves useless, but black still loses.  I think it is better to alter an otherwise sound plan to compensate for 1. a3 than to opt for a more dubious one just to prove that white wasted a tempo.

U tell d4 block Bg7 but then u mean KID, Gruenfeld, and all these defence are bad? Non sense.

Games against 1600-2000 rated players don't mean anything anyway.

Personnally i lost a game as black with 1.a3 g6 2.h4 against a strong GM, but i had a good position, the opening was not the problem.

moves like 1.e3 1.d3 and 1.c3 and perhaps 1.a3 are so unpopular because they have relatively little independent value, not because they are bad. they are probably no better or worse than the other first moves barring the top 4 or 5.