Nimzo-Indian Defense: Classical Variation, Berlin Variation

The move 1. d4 is a very common and strong opening move for White, as it controls the center and prepares for the development of their pieces. By advancing their d-pawn two squares, White not only gains control of the center but also frees up the way for the Queen and Bishop to be developed. This move also opens up possibilities for attacking on the queenside, while at the same time keeping their options open for a more restrained approach. In sum, 1. d4 is a solid opening move for White.

The move 1...Nf6 is a very natural and flexible move for Black. By placing their knight on f6, Black prepares for their own control of the center and frees up the way for their light-squared Bishop to be developed. This move also puts pressure on White's central pawn, and creates the possibility of a counterattack if White advances it further. By playing 1...Nf6, Black keeps their options open for future moves, and responds to White's opening move in a very solid and logical way.

The move 2. c4 is a very common and strong opening move for White. By advancing their c-pawn two squares, White gains further control of the center and prepares for the development of their Queen's Knight. This move also puts pressure on Black's own center and frees up the way for White's other pieces to be developed. In some cases, White may even be able to push their pawn to c5, creating a powerful outpost for their Knight and limiting Black's options for counterplay. In sum, 2. c4 is a sound and aggressive move that sets the stage for a dynamic and tactical game.

In the Nimzo-Indian Defense: Classical Variation, Berlin Variation, Black's move 2...e6 is a solid and popular response. By advancing their pawn to e6, Black reinforces their control over the d5 square and prepares for the development of their light-squared Bishop. This move also creates a solid pawn chain and limits White's options for launching an attack on the queenside. Additionally, by playing 2...e6, Black keeps their options open for future moves such as placing their dark-squared Bishop on e7 or d6. In sum, 2...e6 is a flexible and text-book move for Black in this opening.

The move 3. Nc3 is a natural and common move for White in this position. By developing their knight to c3, White continues to control the center and prepares for the development of their King's Bishop. This move also puts pressure on Black's central pawn, and makes it difficult for Black to advance their own c-pawn without conceding control over the d5 square. Additionally, by playing 3. Nc3, White can potentially coordinate their knights on d5 or push the pawn to e4, further cramping Black's position. In sum, 3. Nc3 is a strong and logical move that sets the stage for a dynamic and tactical game.

The move 3...Bb4 is a common and sound move for Black in this position. By placing their Bishop on b4, Black pins White's Knight on c3 and creates the possibility of exchanging it for one of White's important central pawns. This move also puts additional pressure on White's central pawn structure, and prepares for the development of Black's dark-squared Bishop to a more active square such as d7 or e6. Additionally, by playing 3...Bb4, Black can potentially force White's Queen to a less desirable square such as a3, further disrupting White's development. In sum, 3...Bb4 is an aggressive and solid move that sets the stage for a sharp and strategically complex game.

In the Nimzo-Indian Defense: Classical Variation, Berlin Variation, White's move 4. Qc2 is a popular and flexible move. By placing their Queen on c2, White protects their pawn on c4 and prepares for the King's Knight to be developed without blocking the path of the Queen's Bishop. This move also potentially prepares for a future kingside attack, and avoids exchanging the pawn on c4 with Black's Bishop. Additionally, by playing 4. Qc2, White can potentially prepare for the pawn to be advanced to b3, creating a solid and hard to break pawn chain. In sum, 4. Qc2 is a solid and text-book move that continues to put pressure on Black's central pawn structure and sets the stage for a strategical and positional game.

The move 4...c5 is a common and dynamic response for Black in this position. By advancing their pawn to c5, Black breaks White's grip on the center and challenges the pawn on d4. This move creates counterplay by making it more difficult for White to develop their pieces, and it also opens up the way for Black's Queen's Bishop to be developed. Additionally, by playing 4...c5, Black can potentially obtain control over the d5 square and launch a queenside attack, or alternatively establish a firm pawn chain to limit White's counterplay. In sum, 4...c5 is an aggressive and solid move that sets the stage for a sharp and complex game.