Nimzo-Indian Defense: Three Knights Variation, Korchnoi Variation

The Nimzo-Indian Defense starts with the moves 1.d4 Nf6 2.c4 e6. White's move, 3.Nc3, supports the central pawn and prepares to develop the kingside knight. Black responds by playing Bb4 and attacks the knight on c3. This move aims to create a weakness in White's pawn structure on d4. The move, 4.Nf3, defends the knight on c3 and prepares to castle kingside. Black continues with c5 to control the d4 square. White's response 5.d5 opens up the center and creates a passed pawn. This move aims to gain space and put pressure on Black's position.

Black's move Nf6 is a flexible move that develops a minor piece and prepares to control the central squares e4 and d5. By placing the knight in front of the pawn on d7, Black creates a threat of d5, which unbalances the center. This move also prepares to play e6 and Bb4, pinning White's knight on c3 or attacking the pawn on d4. By developing a piece and controlling central squares, Black aims to establish a solid position and prevent White from gaining too much space.

White's move c4 is a classic idea in the Queen's Pawn Opening, aiming to control the central dark squares, d5, and e5. By advancing the pawn, White seeks to gain control of the center and restrict Black's pawn on d7. This move also prepares to develop the knight to c3, attacking the central squares and preparing to castle kingside. By advancing the c-pawn and supporting the central pawn on d4, White aims to establish a strong pawn center and create opportunities for piece development.

In the Nimzo-Indian Defense: Three Knights Variation, Korchnoi Variation, Black's move e6 is a standard response to White's move c4. This move prepares to develop the light-squared bishop to b4 and create pressure on White's central pawn on d4. By playing e6, Black aims to control the central squares d5 and f5, establish a solid pawn structure, and prevent White from gaining too much space. This move also prepares to castle kingside and connect Black's rooks. In sum, e6 is a flexible move that allows Black to respond to White's future developments.

White's move Nc3 in response to Black's e6 in the Queen's Pawn Opening is a typical developing move. By moving the knight, White aims to control the central squares and prepare to castle kingside. Nc3 also supports White's pawn on d4 and prepares to build a strong pawn center. This move also puts pressure on Black's pawn on e6, discouraging Black from advancing the pawn to e5 and limiting the scope of Black's light-squared bishop. In sum, by developing a minor piece, White aims to establish a flexible and dynamic position.

Black's move Bb4 in response to Nc3 in the Queen's Pawn Opening is known as the Nimzo-Indian Defense. This move creates pressure on White's knight on c3 and aims to exchange it for a bishop or weaken White's pawn structure. Bb4 also establishes a pin on White's knight, restricting its movement. This move prepares to develop Black's light-squared bishop to e7 or a6 and support the pawn on d5. In sum, Bb4 is a flexible move that allows Black to create imbalances in the position and prevents White from establishing a strong pawn center.

In the Nimzo-Indian Defense: Three Knights Variation, Korchnoi Variation, White's move Nf3 in response to Black's Bb4 is a standard developing move. By moving the knight, White aims to control the central squares, prepare to castle kingside, and support the pawn on d4. Nf3 also creates a threat of e4, which would attack Black's knight on e5 and gain more control of the center. This move prepares to develop the light-squared bishop and connect White's rooks. In sum, Nf3 is a flexible move that allows White to respond to Black's future developments and maintain a solid pawn center.

Black's move c5 in response to Nf3 in the Queen's Pawn Opening is a common break that aims to challenge White's control of the center. This move attacks White's pawn on d4 and creates a central pawn duo. By advancing the pawn, Black aims to gain space and counter White's pawn center. c5 also prepares to develop Black's light-squared bishop and create pressure on White's position. This move is often played in the opening when Black wants to create dynamic play and force White to make difficult decisions. In sum, c5 is a flexible move that allows Black to choose between different pawn structures and tactical possibilities.

White's move d5 in response to Black's c5 in the Queen's Pawn Opening is a common break that aims to gain space and create a passed pawn. By advancing the pawn, White aims to control the central squares and prevent Black from playing d5. d5 also opens up White's light-squared bishop and creates pressure on Black's pawn on c5. This move often follows a plan of playing f3 and e4, establishing a strong pawn center and limiting Black's pawn breaks. In sum, d5 is a strategic decision that requires careful consideration of Black's potential reactions and tactical possibilities.