Petrov's Defense, Classical Attack

To read algebraic notation, the letter marks the column and the number marks the row; e5 is column e, row five. Petrov's Defense begins when Black answers the attack on e5 by attacking White's e4-pawn in return. In the Classical Attack, White captures on e5, retreats the knight when challenged, and allows Black to recover the pawn. White then advances the d-pawn to d4, occupying the center and preparing new ways to challenge the black knight on e4.

Black commonly answers by placing a pawn on d5 as well. The pawn structure becomes nearly symmetrical, but the knights are not placed symmetrically: Black’s knight on e4 is advanced and can be challenged by white pieces and pawns. White tries to gain time by attacking it while bringing the pieces into play. Black keeps it only while it remains useful, then exchanges or retreats it before it becomes a burden.

Although the structure looks balanced, the line contains tactics involving the central knight, the d4-pawn, and the opening of the e-file. Both sides should finish bringing the pieces into play and secure the king before beginning more ambitious operations.