Nimzo-Indian Defense: Classical Variation, Milner-Barry Variation

The Nimzo-Indian Defense is a popular opening for Black that begins with 1. d4 Nf6 2. c4 e6. White's third move, Nc3, is an attempt to control the center but also allows Black to pressure the center with Bb4. White's fourth move, Qc2, defends the pawn on c4 and aims to develop the queen to a more active square later on. Finally, Nf3 develops a knight and prepares to castle kingside. In sum, White's opening strategy revolves around controlling the center and keeping pieces active and ready for action.

After the move 1.d4, playing Nf6 is a common response by Black. By developing the knight to a central square, Black intends to control the center and exert pressure on White's pawn on d4. Additionally, Nf6 prepares to castle kingside and develops a minor piece, making it a flexible move. Playing Nf6 also opens up possibilities for Black to later play e6 or g6 and develop their dark-squared bishop. In sum, Nf6 is a solid and versatile move for Black in response to 1.d4.

White's move c4 after 1. d4 Nf6 is a crucial step in taking control of the center. By advancing the pawn two squares, White puts pressure on the pawn on d5 and prepares to stake a claim in the center with their pieces. The move c4 also helps to develop the queen's bishop, which can potentially be fianchettoed in the future. By playing c4, White aims to establish a strong and flexible pawn structure that allows for a wide range of possible pawn chains and breaks. In sum, c4 is a key move in many popular openings in chess.

In the Nimzo-Indian Defense: Classical Variation, Milner-Barry Variation, Black's move e6 is a central response aimed at controlling the light squares and freeing up the bishop on c8. By playing e6, Black creates a pawn chain that supports pieces on d5 and f5, making it easier to defend against enemy pieces. Additionally, e6 prepares to develop the light-squared bishop to a more active square, potentially on the diagonal b7-g2. By playing e6, Black seeks to establish a solid position with adequate control over the center in preparation for any further white advances.

White's move Nc3 after 1.d4 Nf6 and 2.c4 e6 is a common response that looks to reinforce their control over the center. Nc3 prepares to support the pawn on d4 and challenge any attempts by Black to further pressure the center. Additionally, Nc3 develops a minor piece towards the center, with the added benefit of potentially controlling the b5-square later on. This move also opens up possibilities for White to play d5 in the future, further expanding their control over the center. In sum, Nc3 is a natural move as part of White's opening strategy and positions the knight defensively while maintaining control over squares in the center.

Black's move Bb4 after 1. d4 Nf6 2. c4 e6 and 3. Nc3 is a common response that aims to pressure White's control over the center. By developing the bishop and pinning the knight on c3, Black creates a potential weakness in White's position that could allow for tactical opportunities in the future. Additionally, Bb4 prepares to castle kingside safely and can potentially allow for exchanges of the active knight on c3, which could eliminate a key defender of White's pawn structure. By playing Bb4, Black seeks to create counterplay and restrict White's options, thereby applying pressure and challenging White's opening strategy.

In the Nimzo-Indian Defense: Classical Variation, Milner-Barry Variation, White's move Qc2 after 1.d4 Nf6 2.c4 e6 and 3.Nc3 Bb4 is a common maneuver that serves a few purposes. Firstly, it defends the pawn on c4, which is under attack by Black's bishop. Secondly, it allows White to later develop their queen to a more active square, potentially on the c-file or to a5. Finally, Qc2 keeps flexibility in the position, allowing White to choose between different strategies and adapt to Black's moves. Additionally, Qc2 prepares to castle kingside and potentially enables White to attack Black's kingside later on. In sum, Qc2 is a useful and versatile move that helps White to centralize pieces and prepare for future operations.

Black's move Nc6 after 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 and 4.Qc2 is a flexible response that aims to develop a knight and prepare to castle kingside. Additionally, Nc6 puts pressure on White's pawn on d4, forcing them to defend it and potentially opening up tactical options for Black. Nc6 also prepares to support the pawn on e6, which is a key pawn in Black's center pawn chain. Lastly, Nc6 develops a minor piece to a potentially active square, allowing Black to build towards a solid and functional position. In sum, Nc6 is a useful multi-purpose move that prepares for various strategies while maintaining a strong and solid position.

White's move Nf3 after 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 and 4.Qc2 Nc6 is a key maneuver that develops a knight and prepares to castle kingside. By playing Nf3, White solidifies their control over the center and prepares to mobilize other pieces. Additionally, Nf3 develops a minor piece to an active square while maintaining flexibility in the position. It also prepares to support the pawn on d4, which is still under attack from Black's knight on c6. Lastly, playing Nf3 opens up potential future lines for the queen, either along the d1-h5 diagonal or the g1-a7 diagonal. In sum, Nf3 is a strong and versatile move that aims to improve White's position and maintain control over the center.

In the Nimzo-Indian Defense: Classical Variation, Milner-Barry Variation, Black's move d6 after 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Qc2 Nc6 and 5.Nf3 is a common response that aims to reinforce and further support Black's central pawn chain. d6 also prepares to develop the light-squared bishop to a more active square and allows for additional flexibility in Black's position to adapt to future moves from White. By playing d6, Black strengthens their position and prepares to continue developing their pieces. Additionally, d6 prevents any potential pawn forks involving the knight on c6 and can serve as a pivot point for Black to launch a future pawn break or attack. In sum, d6 is a useful and flexible move that helps to solidify Black's position and prepare for future play.