Markovich wrote on 07/05/09 at 21:51:56:


Indeed. Which is why white takes on d5 (4. ed5)

Sorry, bad reading from my side - once again.

That Arencibia game seems like another typical case of "more games needed before we can draw any conclusion." But you seem to be right that 3.g3 is a full-fledged alternative for 3.d4. It's something practioners of 3.Bb5 should keep in mind.

But can't Black come very close to a transposition to that Ljubo-Kaspy game with 6.d3 g6 ? If yes Black's new problems are solved within less than 10 moves .....

But Black can play such a cat and mouse game as well: 1.e4 c5 2.Nf3 e6 3.g3 Nc6 4.Bg2 Nge7 5.0-0 and only now d5.

Very informative post by Tracke, making it easy to see the point of 3...d5. Delchev & Semkov just mention that Black is ok after 3...d5 4.e5 Nc6 5.Bg2 and then either 5...g5, 5...f6 or 5...Qc7 followed by ...g5.

That Ljubo-Kasparov game is a real treat, a reminder of Kasparov's mightiness against unambitious play.

3.g3 is a useful tool against 2...e6 if white wants to avoid open variations. 
For example because you prefer Bb5(+) systems against 2...d6 & 2...Nc6 
Other possibilities are 3.c4, 3.d3, 3.b3, 3.c3, 3.Qe2 etc. None of them can 
promise much (or even little) advantage but certainly they all have some bite. 
I play them all in an alternating way.

The most important idea behind 3.g3 is certainly to play an KIA setup 
with d2-d4 in one go (after Bg2/0-0/c3), then white might have += . 
This most often only works if black plays so slowly that white manages 
to protect pawn e4 with Re1 after Nf6. Or if white is ready to castle after 
...d5 ed5 ed5 without being disturbed by ...Qe7+ or ...Bb4+ . Therefor 
black should avoid too many waiting moves like ...Nc6, ...a6, ...Qc7, ...Be7 
etc. (what happens much often among weaker hedgehog devotees!)

Of couse there are many other motivs (depending of black´s answer):
- to transpose to real KIA lines with d2-d3 [as mentioned by zoo]
- to transpose to g3-systems of open sicilians with d2-d4
- to play (like Rozentalis) a kind of c3 sicilian with g3 inserted

White is very flexible in chosing a favourable line as long as black doesn´t 
challenge e4! Both 3...Nf6 4.e5! and 3...b6 4.d4! are no clear equalizers. That´s 
why 3...d5(!) is the critical and probably best answer (at least in my opinion).

After 3...d5 4.exd5 exd5! (4...Qxd5 5.Nc3 +=) White has four choices:
- 5.Qe2+ Be7 (misplacing the Q, unclear)
- 5.Bg2 Qe7+ 6.Qe2 Qxe2+ 7.Kxe2 (equal but somewhat dull)
- 5.Bg2 Qe7+ 6.Kf1 (sophisticated and unclear)
- 5.d4 (to answer ...Qe7+ with 6.Be3) Nc6 6.Bg2 Bg4 (unclear, might become
  more tactical - as seen in Car-Rad - than 3g3 players usually want to!)

Summarizing 3.g3 might be a sound and interesting sideline with some practical 
venom. In many lines white has a little edge and against 3...d5 at least a wide 
choice between different kinds of play. But to be honest, it doesn´t seem to 
promise anything against a well prepared black player. On the other side there´s 
not much theory and still much scope for home preparation and creativity.

There are not many theoretical sources. obviously only Emms´ article
"A Turbo-Charged King's Indian Attack" (22 pages, from white´s point of view) 
in Dangerous Weapons - Anti-Sicilians. And a short antidote (don´t know 
much about that) in "The Safest Sicilian" by Delchev/Semkov.

tracke 

Basically, White hopes to play d3, Nbd2,e5 (the key move), then Qe2, 0-0, Re1 (to support e5 with help of Nf3), perhaps Bf4 and then the famous/automatic plan h4, Nd2-f1-h2, Ng5, Qh5. Meanwhile Black rushes all his Queenside pawns with typical structures like c5,b5-b4,a5-a4-a3,Ba6,Nb6, c4. Since Black will eventually break through in the Queenside, all White's hopes rely on his mating attack. Despite the slow opening there are very few draws in this variation, mostly by perpetual check.
If Black doesn't want to play ball, he just can play ...e6-e5, losing a tempo against the ideal ...e7-e5. But still this is ok for him (in fact this is why this set-up is played only after ...e6, as against ...e7-e5 it loses its teeth). Black then goes for standard anti-sicilan set-up with g6,Bg7,Nge7,00,d6,h6,Be6 aiming for ...Rb8/b5-b4, ...d5 or ...f5.  
This setup is known as King's Indian Attack (KIA) and mostly seen after the move-order 1.e4 e6 2.d3 d5 3.Nbd2 followed by g3,Bg2 etc. You may find more relevant games with this move order. A famous player with that system was Bobby Fischer, as well as Morozevich.