In opposition to the d4 opening from white, the Queen's Indian Defense is an exceptionally useful modern defense who takes control at the center using black's pieces. By bringing black's knight to c3 and rather opting to first bring white's knight to f3, it mostly arises when white chooses to evade the Nimzo-Indian defense.
In this video, the instructor discusses some variations of the Queen's Indian Defense and how the play usually will start. The emphasis is on black's option to play b6 by preparing to fianchetto the light square bishop and attempt to control the center light squares and also the long diagonal line.
White has few choices but will mostly choose g3, which can challenge the long diagonal by fianchettoing its own bishop to g2. Then black has two options to choose from, whether playing passively by taking bishop to b7 or doing the aggressive move by bringing the bishop to a6.
The instructor suggests to take black's many chances to play aggressively, and one is attacking the pawn in c4 since white does not have a lot of options to defend it. By this move, black has the higher probability of controlling the center and taking a great advantage. This makes the Queen's Indian Defense famous at top level play unlike some Indian defenses.
Check out the video to get a thorough explanation of Queen's Indian Defense opening. Then work it into your games and see the results!