Hosted by GM Leonid Kritz
GM Kritz outlines several variations of the Queens’s Indian including The Main line and the Main Modern Line. Including 4.g3. Plan 4....Ba6.5.b3 b5 The Queen's Indian is regarded as the sister opening of the Nimzo-Indian, since both openings aim to impede White's efforts to gain full control of the center by playing e2–e4.
Queen's Indian - Theory and Practice - 4.g3, Plan 4.. Ba6, 5. b3 b5 - Chess Lecture - Volume 125