Pterodactyl Defense: Eastern, Benoni

This chess opening features an early fianchetto of the dark-squared bishop and a pawn break with c5, leading to an imbalanced position.

The opening is a flexible and somewhat unorthodox choice for Black, aiming to create an imbalanced position and catch the opponent off guard. It is part of the Modern Defense family, where Black allows White to occupy the center with pawns and then tries to undermine it later. The Eastern variation of the Pterodactyl Defense is characterized by the pawn break with c5, which is reminiscent of the Benoni Defense.

In this opening, Black's main idea is to challenge White's pawn center with moves like c5 and e6, while also preparing to strike at the d4 pawn with moves like Nf6 and exd5. The fianchettoed dark-squared bishop on g7 plays a crucial role in Black's strategy, as it exerts pressure on the long diagonal and supports the pawn breaks.

White, on the other hand, can try to exploit Black's somewhat passive setup by expanding in the center and on the kingside. The most common plan for White is to play f4 and Nf3, followed by Bd3 and O-O, aiming for a kingside attack.

The Pterodactyl Defense: Eastern, Benoni is not as popular or well-studied as other openings, which can be an advantage for Black players who are well-prepared and looking for a surprise weapon. However, it can also lead to sharp and complex positions, requiring a good understanding of the resulting pawn structures and piece play.