Why G6?

why is the G6 opening better than B6 ?  Why is the G3 opening better than B3?

g6/b3 prepaires castling and supports a queen side attack. But b6 is played in many openings as well, just it is not good against 1. e4. And b3 is just not aggressive enough, it will transpose into something like a queen's indian defence probably, which is not what white wants.

ok im trying to learn so please dont think im defending one opening over the other.  G6/G3 supports a queenside attack.  Wouldnt it be better to support a kingside attack since the object is to take down the King?  

That's a good question... I'm not sure what the best answer is.

I'm going to use the term "finachetto" which is when the b or g pawn moves and a bishop is put in its place.

Just very quickly on the subject of attack.  In chess you alternate turns (of course) so both players usually agree on what their trumps will be.  Unless you go wild for an attack you can't always guarantee a mating attack will be the best plan for you.

On the subject of "best" I'm not sure I'd say a kingside fianchetto is strictly better than a queenside fianchetto.  But if you looked at every game played in the last 100 years a kingside finachetto may be more common for two reasons.  With a kingside finachetto you can castle faster and the bishop servers a dual purpose of pointing at the center / queenside while adding some defense to the king.

On the subject of attacking the castled king, that's an interesting thought.  I actually wouldn't characterize an early finachetto as an aggressive move attacking the opposite side even though it seems like it would be.  Somewhat counter-intuitively, I think for attacking, the bishops are best on their original diagonal i.e. the queen's bishop is best on c1/c8 when attacking the kingside.

So again two reasons.  First is a bit simple, it's not very flexible.  It's just on the long diagonal.  The opponent may block that diagonal or fortify f3/f6 or g2/g7 and then what?  Attacks almost always involve superior mobility in the area you're attacking.  If a b2 bishop could force a fortification of f6 then swing around quickly to h6 and hit g7... but it can't.

Second reason is the other element that makes attacks good which is space.  Most attacking positions involve one of two types of pawn configurations.

First is an attacking wedge (pawn on e5 for white or e4 for black).  This pawn gets rid of a knight on f3/f6 which is often a key defender and gives the attacker more space to work with.  Unfortunately it also blocks a would be queenside finachettoed bishop.  Usually you see the queen's bishop on the original diagonal and sacrifice itself on h3/h6 or maybe pin a knight on f3/f6.

Second kind of pawn participation is just a pawn storm.  The pawns rush forward, often sacrificing themselves, to open lines of attack.  To counter this best is to counter attack in the center.  The kingside attacker wants his pieces behind this wave of pawns ready to jump into any holes they open up.  A queenside finachetto would likely either get blocked in the ensuing central counter or again not be flexible enough to jump into a hole that appears.  (White's queen bishop on its original diagonal can go to f4, g5, or h6 for example).

However sometimes a b2/b7 bishop is an excellent attacking piece.  Usually this is after the central pawns are cleared out (no one has center pawns, or they're far advanced and off the diagonal) and there are dark square weaknesses white can hit (or light square weaknesses black can hit) usually in tandem with a queen (either as a battery or simply on h3/h6 or g4/g5).

Awesome reply waffllemaster!  If using B6 or B3, one could also castle queenside and use a pawn storm to attack oppenents kingside?  

Oh, I forgot to mention another common attacking diagonal which is a2-g8 for white or a7-g1 for black.  A bisohp on this diagonal hits the f2/f7 sqaure pinning the pawn and sometimes sacrificing.

About the quoted part, sure.  Some of the scariest / most fun positions in chess involve opposite side castling and both players rush to see who can checkmate the other first.  If the center pawns end up just right, the finachetto bishop would be doing a lot of work!  Defending your king and attacking theirs.  As above, often the center gets too cluttered for this, but it's not a bad formation in itself.

If attacking the king is your primary objective, there are far better options for accomplishing that than b3 or ...b6.  

Thanks guys :)

I feel like I should have mentioned cases where a finachettoed bishop is pointed at the side where castling didn't happen.  e.g. a siciilan dragon for black or catalan for white and the fianchettoed bishop is helping attack the queenside in general.

If you fianchetto one of your bishops very early and without a center you are playing with fire. This is hypermodern thinking which is dangerous.

This isn't 1925.  

It is true that the orthodox school was challenged in the early 20th century. But exactly when was it defeated?

I dunno, Carlsen finachettoed both bishops today vs Anand in the first game of the world chess championship... yeah it reminded me of an internet game, and yeah white drew, but I wouldn't call it dangerous (and this is fianchettoing both).

Fianchettoing 1 is part of... probably at least half of all major openings.

But not on the second move. If all that you do is play b3/6 or g3/6 on the first move just to fianchetto on the second you are playing with fire. With white you may get away with it because you are a tempo up but with black it is pure crazyness.

I consider the KID sound, and therefore 1...g6 2...Bg7 is fine.  

The classical thinking (place your pawns in the center) and the hypermodern thinking (it is already not "hypermodern" but the name stays on it :D) (you can control the center with distant pieces and later attack your opponents center) are equal ideas.

What does the principle say? Control the center. Does the classical and the hypermodern control the center? Yes, then it is equal.

However, you first need to understand the classical ideas to be able to understand hypermodern ones. 

This question depends on a concrete position. For example, in the sicilian you usually fianchetto your Q-side bishop, in the nimzo/queen's indian as well, but in the gruenfeld, KID, Pirc defence, english opening and the list goes on you fianchetto your bishop to the king side.

What waffllemaster wrote is very good. 

this is crazy:

Even opponents of the Catalan system admit that it is very stable system for white for at least a comfortable draw. In this opening the fianchettoing of the light square bishop is pivotal. But first white puts a pawn in the center ( 1. d4 ) then attacks black's center with a pawn ( 2. c4 ) then plays Nf3 and when everything is secure starts fianchettoing the bishop. This is by far not a hypermodern opening yet the fianchetto element is very important in it.

Yes I agree, Owen's defense blows.