Nimzo-Indian Defense: Sämisch Variation, O'Kelly Variation

Chess players often start with 1.e4 or 1.d4, but many grandmasters prefer the latter since it allows more control over the center of the board. In the Nimzo-Indian Defense, Black aims to control the center with their knight, which can cause trouble for White. To counter this, White plays 4.a3 to force Black's bishop to move, while also preventing the knight from jumping to b4.

1.d4 is a strong and aggressive opening move for White, but it allows Black to respond with 1...Nf6 which develops a piece and controls the center. By placing the knight on f6, Black is indirectly attacking White's e4 pawn which can put pressure on White's position. Nf6 also allows Black the flexibility to support their own pawn push to d5, and can lead to several different openings depending on White's response.

White's move 1.d4 followed by 2.c4 is known as the Queen's Pawn Opening. c4 is a strong move that aims to control the center, especially the d5 square, and frees up White's queen bishop to be developed. By playing c4, White also puts pressure on Black's knight on f6, making it difficult for Black to push forward with d5. Additionally, c4 can lead to several different variations and openings depending on Black's response.

In the Nimzo-Indian Defense: Sämisch Variation, O'Kelly Variation, Black plays 2...e6 with the aim of supporting the pawn to d5 and gaining control of the center. This move prepares Black to respond to White's d4 pawn push with a pawn of their own, as well as allows the bishop on c8 to be developed. By playing e6, Black also puts indirect pressure on White's pawn on c4, discouraging White from pushing it forward to c5. In sum, e6 is a solid move that sets up a strong central pawn structure for Black.

After the moves 1. d4 Nf6 2. c4 e6, White plays 3.Nc3 with the aim of developing a piece and controlling the center. By placing the knight on c3, White supports their pawn on d4 and prepares to castle kingside. Additionally, Nc3 stops Black's knight from jumping to e4 and attacking White's pawn on d4. This move also frees up the queen to be developed, and prepares for the potential push of the b-pawn to b4. In sum, Nc3 is a strong and flexible move in the Nimzo-Indian Defense: Sämisch Variation, O'Kelly Variation.

In the Nimzo-Indian Defense: Sämisch Variation, O'Kelly Variation, Black plays 3...Bb4 with the aim of attacking White's knight on c3 and disrupting White's development. This move is also known as the Nimzo-Indian Defense, a well-respected and popular opening for Black. By playing Bb4, Black also puts pressure on d4 and can weaken White's pawn structure if the bishop is captured. Additionally, this move allows Black to develop their light-squared bishop and castle kingside. In sum, Bb4 is a strong and dynamic move in the Nimzo-Indian Defense.

In the Nimzo-Indian Defense: Sämisch Variation, O'Kelly Variation, White plays 4.a3 with the aim of forcing Black's bishop to retreat and blocking the potential move of Black's knight to b4. By playing a3, White also gains space on the queenside and frees up their dark-squared bishop to be developed. Additionally, a3 prevents Black's b4 pawn push, which can disrupt White's pawn structure. In sum, a3 is a useful prophylactic move that can limit Black's options and create future attacking chances for White.

After White plays 4.a3 in the Nimzo-Indian Defense, Black plays 4...Bxc3+ with the aim of gaining control of the center and disrupting White's pawn structure. By capturing on c3, Black doubles White's pawns and creates a semi-open b-file that can be used for future attacks. Additionally, this move develops Black's bishop and puts pressure on White's pawn on d4. By taking on c3, Black also avoids the potential of losing their bishop due to retreating it to b6. In sum, Bxc3+ is a strong and flexible move in the Nimzo-Indian Defense.

After Black captures on c3 in the Nimzo-Indian Defense with 4...Bxc3+, White plays 5.bxc3 with the aim of maintaining their central pawn structure and support for their d4 pawn. By taking with the b-pawn, White avoids doubling their pawns on the c-file and creates an open b-file that can potentially be used for attacking chances. Additionally, bxc3 allows White to develop their queen to b3, which threatens Black's pawn on b6 and indirectly attacks their knight on f6. By playing bxc3, White also gains space on the queenside and frees up their light-squared bishop to be developed. In sum, bxc3 is a solid move that maintains control of the center and creates future attacking chances for White.

In the Nimzo-Indian Defense: Sämisch Variation, O'Kelly Variation, after White takes with bxc3, Black plays 5...c5 with the aim of controlling the center and attacking White's pawn on d4. By pushing the pawn to c5, Black gains space on the queenside and puts pressure on White's pawn structure. Additionally, this move can open lines for Black's queen and bishop on c8, creating potential attacking chances. By playing c5, Black can also prepare to push d5, which can further disrupt White's position. In sum, c5 is a strong and aggressive move that allows Black to seize the initiative in the game.

After Black plays 5...c5 in the Nimzo-Indian Defense, White plays 6.e3 with the aim of controlling the d4 square and providing support for their pawn on d4. By playing e3, White also clears the way for their light-squared bishop to be developed and prepares for a potential pawn push to d5. Additionally, e3 can prepare for White's queen to be developed to d2 or c2. By playing e3, White also prevents Black's knight from jumping to e4, which can put pressure on White's position. In sum, e3 is a solid and flexible move that maintains control of the center and creates future development opportunities for White.

In the Nimzo-Indian Defense, after White plays 6.e3, Black plays 6...b6 with the aim of developing their bishop on the long diagonal and preparing to castle kingside. By playing b6, Black also gains control of the c5 square and limits White's options on the queenside. Additionally, b6 can prepare for Black's queen to be developed to a6, which can put pressure on White's pawn on b2. By playing b6, Black also prevents a potential pin on the c5 and d6 squares by White's light-squared bishop. In sum, b6 is a flexible move that allows Black to develop their pieces and maintains control of the center.