1.g3 Benko - mainLine

Benko/Hungarian mainline

source:

Chess Opening Essentials - Vol 4 - 2010 - Djuric - Komarov - Pantaleoni

1.g3

Frequently transposes to

       English

       King's Indian Attack

       Reti

       Catalan

1...d5

       2...f6

       2...g6

       2...c5

       2...e5 usually transposes to the mainline

2.g2

       2.f3 prevents 2...e5 and transposes to Reti/KIA.

2...e5

Here we have a Modern Defense reversed with an extra tempo. However, the authors say it is not enough to guarantee White the advantage.

       2...c6 is a popular choice and 

       can lead to a distinct line

       which does not transpose.

       3.d3 f6 4.d2 e5 5.e4 d6 

       6.c3 (6.f3 is a KIA)

       6...O-O 7.e2 e6

                Makropoulou vs Kouvatsou  2004  1-0

3.d3

       A) 3.c4 exploits the extra tempo 

                  and leads to complexity

             3...c6 4.cxd5 cxd5 5.d4 e4 

             Markowski vs Krasenkow  2009

       B) 3.f3 takes inspiration from 

                    the Alekhine Defense

             3...e4 4.d4 c5 5.b3 c4

             6.d4 c5 7.c3

             Grigorian vs Alburt  1977

3...f6

       4.f3 f6 is a reverse Pirc

       4.c4 d4 5.f3 f6 is a Reti/Advance variation

4.d2 c6 5.c3 a5

Sooner or later White should play f3

creating a reverse Pirc/Classical though

the extra tempo is not significant.

5 moves

1.g3 - d5
2. c4  does this belong to the Reti or Benko or... ?

It's a reversed type of (old) benoni. 

1.g3 d5 2.c4 is (A00) Benko's Opening

The line shown above is the closest we have found to a 1.g3 Mainline. 1.g3 is basically a transpositional tool. It allows White to chose an opening after seeing what Black is planning. And of course it also allows Black to have at least a little influence in White's decision.

After 1.g3, transpositions abound.