Ruy Lopez: Old Steinitz Defense, Semi-Duras Variation

The Ruy Lopez opening, also known as the Spanish game, begins with white's move e4. This move aims to grab control of the center, and put pressure on black's position. By occupying the center, white is able to control vital squares on the board, and create opportunities for attacks. In addition, e4 also frees up white's light bishop to be played to the more active b5 square, putting immediate pressure on the black knight on c6. This makes e4 a solid and often played choice for white in the opening phase of the game.

Black's move e5 is a common response to white's e4 opening move. By doing so, Black also aims to control the central squares and to challenge white's control of it. Additionally, e5 frees up Black's dark bishop to be played to a more active square. However, playing e5 also exposes the black pawn to potential attacks, and careful consideration must be given to avoid allowing white to gain an early advantage. All in all, the decision to play e5 is a crucial one for Black in setting the tone for the remainder of the game.

White's move Nf3 is a natural development move in the opening. It creates a threat to the black pawn on e5 and allows the knight to control the d5 square, strengthening White's hold on the center of the board. By playing Nf3, White also prepares to castle kingside and brings another piece closer to the action. However, Nf3 also blocks the way of the f1 bishop, which means that White must be careful not to weaken their center with pawn moves to f3 or f4. In sum, Nf3 is a solid and often-played move in the opening that facilitates strong central control and sets up the rest of the game.

In the Ruy Lopez: Old Steinitz Defense, Semi-Duras Variation, Black's move Nc6 is a typical reply after White's Nf3. The knight move attacks the e4 pawn, applying pressure on White's center and prepares the d7-d5 advance, contesting the central control. The knight on c6 also allows Black's knight to be developed to a more natural square, and it prepares to castle kingside. Moreover, a knight on c6 also prevents White's knight on d5 from attacking the f7 pawn in some positions. In sum, Nc6 is a solid developing move, which allows Black to put pressure on White's center and create more harmony between the pieces.

White's move Bb5 in response to Black's Nc6 is the hallmark of the Ruy Lopez opening, a popular choice for many players. The bishop pins the knight on c6, preparing to capture the pawn on e5 in the future, while also creating a threat on the black knight itself as well as advancing the development of the bishop. The move also adds further pressure on Black's position by targeting the f7 square and preparing the way for the white knight to move to a more central square. In sum, Bb5 is a strong move that helps White to control the center, mobilize their pieces and apply pressure on Black's position.

Black's move d6, in response to White's Bb5, is part of the Old Steinitz Defense, which aims to mitigate the pressure that White puts on the center and develop the pieces harmoniously. The move creates a choice for White, whether to exchange the bishop for Black's knight, strengthening Black's pawn structure or retreat the bishop to a less active square. The move also creates a solid defense for the f7 pawn, restricting the movements of White's bishop. Additionally, the pawn on d6 prepares Black to play the pawn to d5, creating more space and control over the center. In sum, d6 is a solid developing move that aims to control the center while creating a flexible position.

In the Ruy Lopez: Old Steinitz Defense, Semi-Duras Variation, White's move d4 is a common response to Black's d6 move. The move aims to maintain control of the central squares and gain space on the board. Additionally, d4 reinforces White's hold on the e5 pawn, preparing the way for the white bishop to move to a more active square. The move also prepares to open the center of the board, which can lead to tactical opportunities. However, White must also be careful not to overextend their position, as d4 can leave White with isolated pawns on d4 and c4, which can become targets for Black's pieces. In sum, d4 is a strong move that aims to optimize White's position and put pressure on Black's position.

Black's move Bd7, in response to White's d4 move, is a developing move aiming to protect the c6 knight and increase the control over the central d5 square. The move also prepares Black for a potential exchange on d4 in case White takes the pawn on e5. Additionally, the bishop on d7 allows for the queen to be moved to a more active square, and potentially opens up the diagonal for future tactical opportunities. Finally, by putting the bishop on d7, Black prevents a possible pin after Bxc6 bxc6 by not swap the bishop on c6 with a knight, keeping more dynamic options available for Black. In sum, Bd7 is a useful move that allows Black to maintain flexibility and increase their control over the center of the board.

White's move c4, following Black's Bd7 move, aims to gain further control over the central squares and create more space for White's pieces. By playing c4, White also aims to free up the c1 bishop, which can potentially be developed to the square b5, targeting the weakened black pawn on d7 and/or the c6 knight. The move also puts pressure on the d6 pawn by creating a difficult decision for Black if they answer the move with c5. However, c4 also weakens the d4 pawn, making it a target for Black's pieces. Consequently, it is important for White to be cautious and develop their pieces carefully to avoid creating irreparable weaknesses in their position. In sum, c4 is a dynamic move, setting up potential tactical opportunities, whilst aiming to optimize White's central control.