Pterodactyl Defense: Eastern, Benoni Pteranodon

Chess players know that white aims to control the center squares c4, d4, e4 and f4. The move 1. e4 accomplishes this by opening the way for the king's pawn, allowing white to develop a piece and control the center square e5. White can then follow up with moves like d4 and Nf3 to further strengthen the center control.

Black's move g6 is known as the Pirc Defense or the Modern Defense. By playing g6, Black aims to control the center squares indirectly by attacking white's pawn on e4. Additionally, this move allows the bishop to be developed to g7, putting pressure on the d4 pawn. The fianchettoed bishop also provides added defense to the king side. Finally, the move g6 can also lead to a King's Indian Defense setup with moves like d6 and Nf6.

White's move d4 aims to reinforce the control of the center, but more specifically, it aims to target Black's pawn on g6. If black captures with their pawn, then white can capture back with their pawn on d4, further strengthening their control of the center. Alternatively, if Black chooses not to capture the pawn, then white has the opportunity to develop a piece to c3, allowing further control of the d5 square. The move d4 also opens up a diagonal for the light-squared bishop, which can be developed to f4 to pressure Black's king side.

In the Pterodactyl Defense: Eastern, Benoni Pteranodon, Black's move Bg7 aims to develop the bishop and pressure the pawn on d4. By placing the bishop on the long diagonal, Black also adds to the control of the center and puts pressure on the e4 pawn indirectly. Additionally, the bishop on g7 defends the king side and can be used in combination with the pawn on d6 to control the c5 square. The move Bg7 is crucial in this opening as it allows Black to castle king side and brings into play one of their most powerful pieces.

White's move Nc3 in response to 2...Bg7 develops a piece and controls the important d5 square. The knight also supports the central pawn on d4 and prepares to castle king side. Furthermore, with the knight on c3, White can consider playing the pawn to b4 to challenge Black's control of c5 or to develop their bishop on b2 and aim towards the queenside. The move Nc3 is a flexible move that puts pressure on Black's pieces and creates potential threats in the center and on the queenside.

Black's move c5 aims to challenge White's control of the center squares d4 and e5 with a pawn thrust of their own. By playing c5, Black also gains more space on the queenside and further develops their bishop on g7. With the move c5, Black also puts pressure on the d4 pawn and makes it more difficult for White to advance it without making concessions. Additionally, the pawn on c5 gains control of the b4 square, making it more difficult for White to play the move b4 and engage in a queenside pawn structure. The move c5 is a common idea in many types of openings and can be very effective when played at the right moment.

In the Pterodactyl Defense: Eastern, Benoni Pteranodon, White's move d5 aims to control the center and break open the position. The pawn on d5 also puts pressure on Black's pawn on c5 and opens up the possibility for White's light-squared bishop to be developed to b2, with pressure on the long diagonal. From d5, the pawn can also control the e6 square, preventing Black from developing their knight to its ideal post. However, playing d5 comes with risks, as it also opens lines for Black's pieces and can weaken White's control of the center squares, making the position unclear. The move d5 requires careful analysis and calculation to be played effectively.

Black's move Bxc3+ is a tactical response to White's move d5, as it creates a discovered attack on White's pawn on d5. By capturing the pawn on c3 with their bishop, Black can prompt White to recapture with their pawn. This leads to the pawn structure bxc3 and dxc3, which doubles White's pawns and can weaken their pawn structure. Alternatively, if White captures the bishop on c3 with their pawn, then Black can continue to put pressure on the d5 pawn with moves like Qa5 and Rc8. The move Bxc3+ is a typical idea in many openings and can be a powerful tactical weapon when used effectively.

White's move bxc3, which recaptures Black's bishop on c3, aims to maintain control of the center. It also allows the b1-knight to be developed to d2, supporting the pawn on c3 and preparing to develop the bishop to b2. The pawn structure bxc3 and d5xc3 doubles White's pawns, but it also creates a pawn duo that can be used to control important central squares. Furthermore, the move bxc3 opens up lines for White's pieces, including the rook on a1 and the queen on d1, which can target Black's weakened pawn structure. Finally, the doubled pawns can create weaknesses that Black can target later in the game, so White must be careful in how they handle their pawn structure.

In the Pterodactyl Defense: Eastern, Benoni Pteranodon, Black's move Qa5 aims to put pressure on the pawn structure created by White's capture on c3. The move attacks the pawn on a2, forcing White to either move their rook, spend a move defending the pawn, or allow Black to capture the pawn and gain material. Additionally, the move Qa5 can prevent White from castling king side, as the queen places pressure on the g1-a7 diagonal. With the queen on a5, Black is also better positioned to launch an attack on the weakened pawn structure of the king side in the future. In sum, the move Qa5 is a tactical idea that aims to capitalize on the weaknesses created by White's capture on c3.