Queen's Indian Defense: Kasparov-Petrosian Variation, Hedgehog Variation

The opening move d4 by White in the Queen's Indian Defense initiates a strong central control by exerting pressure on Black's e5 pawn. This move serves as a foundation for the subsequent pawn structure that will be created. By placing the pawn on d4, White aims to control the center and bring out its minor pieces to develop its position. This move is also a precursor to creating possible pawn breaks in the center of the board, facilitating a more attacking approach to the game.

Black's move Nf6 in response to White's d4 is a common and solid option, as it also aims to control the central squares of the board. It immediately puts pressure on White's d4 pawn, challenging its central control and limiting the options for White's pieces to move. By bringing the knight out early, Black also aims to develop its pieces and castle its king, which are crucial objectives in the opening stage of the game. Additionally, Nf6 prepares for a potential counter-attack, as it creates threats against White's pawn structure and other pieces.

The move c4 by White is played after developing the knight on f3, creating a strong central pawn formation known as the "d4-d5" pawn chain. c4 serves to reinforce this pawn chain and expand White's control over the center, opening up potential avenues for White's pieces to move and attack. By pushing the c-pawn, White also gains space on the board, threatening to encroach upon Black's position and limiting the mobility of Black's pieces. Furthermore, c4 sets up potential tactical opportunities and allows for the possibility of capturing Black's d5 pawn in the future.

In the Queen's Indian Defense: Kasparov-Petrosian Variation, Hedgehog Variation, Black's move e6 is a common response to White's c4. This move helps control the central squares and prepares to develop the light-squared bishop. By advancing the e-pawn, Black also muscles in on White's central control, posing a challenge to the d4 pawn. Additionally, e6 helps lay the groundwork for a solid pawn structure that is characteristic of the Queen's Indian Defense, which aims to create a fortress-like position that is difficult for White to penetrate. Finally, e6 serves as a flexible move that can be adjusted according to White's future actions, allowing Black to adapt to the unfolding chess board.

The move Nf3 by White is a natural developing move, bringing a knight to a central square and supporting the pawn chain established by d4 and c4. By putting pressure on Black's e6 pawn, Nf3 prepares to play d5, which would further increase White's control of the center and create space for its pieces to move. The knight on f3 also protects the pawn on d4 and opens up the possibility for castling on the king's side. Additionally, Nf3 aims to coordinate with other pieces and prepare for potential tactical opportunities in the future.

The move b6 by Black is a flexible developing move that aims to control the light squares on the board. It prepares for the development of the bishop to b7, which will eye the long diagonal and put pressure on White's central pawn chain. Moreover, b6 reinforces Black's control over the c5 square, since it is no longer under threat by the knight on f3. This move also helps prevent the knight on c3 from developing to d5, which could be a potential threat to Black's position. By playing b6, Black aims for a solid and flexible pawn structure that can adapt to different variations and suit its own strategy.

In the Queen's Indian Defense: Kasparov-Petrosian Variation, Hedgehog Variation, White's move a3 is a well-known plan to prevent Black from developing its bishop to the square b4. This move allows White to reinforce its control over the square c4, making it harder for Black to disrupt the centralized pawn chain. Additionally, a3 helps to prepare for a future expansion on the queenside, by providing a support point for b4. By playing a3 and preventing Black's bishop from attacking the pawn on c4, White maintains a solid pawn structure and can better control the board. Furthermore, a3 also potentially stops counterplay from Black on the a3 to f8 diagonal, which could be a tactical opportunity for Black's light-squared bishop.

The move Bb7 by Black is a natural developing move, bringing out a piece and lining up on the long diagonal. The bishop aims to exert pressure on the pawn chain established by White's d4 and c4 pawns and control key central squares. By developing this bishop, Black reinforces its influence over the b6 square, increasing the flexibility and adaptability of its pawn structure. Additionally, Bb7 prepares to castle on the king's side and potentially coordinate with other pieces, contributing to a strong and cohesive position. Moreover, Bb7 represents a strong defender of the king's side, and it can help prevent White's tactical chances along the a3 to f8 diagonal.

The move Nc3 by White is another natural developing move, bringing out a piece and preparing for potential central pawn breaks. This knight aims to pressure Black's pawn on e6, which defends the d5 square. By occupying the c3 square, Nc3 also supports the pawn on d4, further increasing White's central control. Moreover, Nc3 prepares for a possible future pawn break on d5, which would disrupt Black's pawn structure and create additional space for White's pieces to move. Additionally, Nc3 helps to coordinate White's pieces and puts pressure on Black's pawn structure. Finally, Nc3 prepares for possible tactical opportunities and sets up potential for knights to jump to d5 or b5 squares in the future.

In the Queen's Indian Defense: Kasparov-Petrosian Variation, Hedgehog Variation, Black's move g6 is a common developing move that allows for the bishop to be fianchettoed to g7, opening up the long diagonal for future potential attacks. g6 also prepares for the king to castle on the kingside, which typically happens in this variation. This move helps to control the light squares on the board when paired with Bb7, creating stability in Black's position. Additionally, g6 supports Black's pawn structure and prepares for a possible counterattack against White's central control. By playing g6, Black aims to establish a solid foundation for its pieces, making it challenging for White to exploit any potential weaknesses in Black's position.