Nimzo-Indian Defense: St. Petersburg Variation

Chess players around the world are familiar with the opening move of d4, which aims to control the center of the board and help white develop pieces. It is the most popular first move for white in chess, and for good reason. By playing d4, white can quickly establish control over the center, preparing to move their pawns and pieces push forward towards black's position. This move also supports white's eventual development of a strong pawn chain, as well as provides options for their knights and bishops to quickly occupy key squares on the board.

After white moves their pawn to d4, black responds by placing their knight on f6. This move aims to counter white's control over the center by placing pressure on their pawn. Additionally, the knight on f6 is well-placed to support black's future pawn advances and to help develop their pieces. Importantly, by placing their knight on f6, black also delays committing their other pieces until they have a better sense of white's intentions. This move is a common response to d4 and can be found in many different chess openings.

After placing their knight on f6, black eyes white's pawn on d4. To support this pawn and establish stronger control over the center, white responds by pushing their pawn to c4. This move aims to establish a strong pawn chain and create more space for white's pieces to maneuver. By advancing their pawn, white also hopes to limit the mobility of black's knight on f6 and force it to eventually retreat. Additionally, c4 helps to prepare for the development of white's knight to c3 and bishop to either d3 or e2, depending on the game's circumstances. In sum, c4 is a powerful move that helps white firmly establish their control over the center.

In the Nimzo-Indian Defense: St. Petersburg Variation, after white has played c4 to establish more control over the board, black responds with e6. This move helps support black's pawns and limits the options for white's pawn on c4 to advance further. With e6, black prepares to develop their light-squared bishop to d6 or e7, with an eye towards challenging white's strong pawn chain in the center of the board. Additionally, e6 can help black gain more control over the d5 square and potentially counter any developments made by white on the queen side. In sum, e6 is a solid move that helps black gain more control over the center while preparing for future piece development.

After black has played e6 to reinforce their pawn structure and start developing their light-squared bishop, white responds by bringing their knight to c3. This move helps support white's plans to control the center of the board, as the knight eyes both d5 and e4 squares. Additionally, Nc3 prepares for the eventual development of white's pieces, including their other knight and light-squared bishop. By placing their knight on c3, white can also respond to any potential future attacks on their pawn chain, helping to maintain the stability of their position. In sum, Nc3 is an important move in the opening phase of the game and helps set the stage for future developments.

Following white's move of Nc3, black responds by placing their dark-squared bishop on b4. This move attacks white's knight on c3, creating some tension in the center of the board. Additionally, Bb4 can help prevent white from playing the move d5 in some variations, especially if white has not yet played the move e3. Another potential benefit of Bb4 is that it helps black control the a5 to e1 diagonal, which can be used to challenge white's pawn chain and limit their ability to develop their pieces. In sum, Bb4 is a strong move that can help black gain more control over the center and put early pressure on white's position.

In the Nimzo-Indian Defense: St. Petersburg Variation, after black has played Bb4 to attack white's knight on c3, white has a few different options to consider. One popular move in this position is e3, which helps support white's pawn chain and allows them to continue developing their pieces. With e3, white prepares to bring their light-squared bishop to d3 or e2, with an eye towards challenging black's bishop and establishing more control over the center of the board. Additionally, e3 can also help prevent any potential pins on white's knights, as the pawn on d4 is now well-protected. In sum, e3 is a flexible move that helps white secure their position and prepares for future developments.

After white's move of e3, black can respond with b6, developing their dark squared bishop. With this move, black aims to put pressure on white's pawn chain, potentially preparing to challenge it with a move like c5. Additionally, by placing their bishop on b7, black can gain control over the a8-h1 diagonal, which can be used to launch attacks on white's position or support future developments. Another potential benefit of b6 is that it can create a potential pin on white's knight on c3, which can limit their ability to respond to black's piece movements in the center of the board. In sum, b6 is a solid move that helps black develop their pieces and prepare for future attacks.