Queen's Indian Defense: Petrosian Variation, Farago Defense

This chess opening is a solid, flexible defense that focuses on controlling the center and countering White's pawn advances.

The opening is named after the former World Chess Champion Tigran Petrosian, who was known for his solid and prophylactic style of play. In this variation, Black adopts a hypermodern approach, allowing White to establish a pawn center with the moves d4 and c4, while focusing on piece play and counterattacks. The key move a3 is played by White to prevent Black's light-squared bishop from pinning the knight on f3 to the queen on d1.

Black's setup is characterized by the fianchetto of the light-squared bishop on b7, which exerts pressure on the central e4 square and can potentially challenge White's pawn center. The Farago Defense, named after Hungarian chess player Ivan Farago, involves the early development of Black's light-squared bishop to a6, followed by its retreat to b7. This maneuver aims to provoke weaknesses in White's pawn structure and create counterplay on the queenside.

White's main plan in this opening is to maintain a strong pawn center and gradually expand on the kingside, while Black seeks to undermine White's center and create counterplay on the queenside. Both sides have various options to deviate from the main line, leading to rich and complex middlegame positions.

Overall, this opening is a solid and flexible choice for Black, offering good chances for counterplay and a rich variety of middlegame plans.