Sicilian Defense, Scheveningen Variation, Keres Attack

The Keres Attack begins with 6.g4 against the Scheveningen structure, where Black's pawns stand on d6 and e6. The move controls more squares on the king's side and threatens g5, which would drive away the f6-knight. That knight controls e4 and d5 and helps defend the king, so dislodging it can change how Black's pieces protect one another.

The advance works partly because Black's e6-pawn blocks the c8-bishop. Without that blockage, the bishop could attack g4 along the c8-d7-e6-f5-g4 diagonal. White uses this detail before castling and before moving the remaining pieces from their starting squares.

The reward is control of more squares and time to attack. The risk is that White's king remains in the center and the advanced pawns may become targets. Black usually seeks an immediate reaction with ideas such as ...h6, quick piece development, a pawn advance in the central squares, or counterplay on the queen's side, meaning threats of Black's own that force White to slow the attack. Passive play may allow g5 under favorable conditions.

The Keres Attack is not merely an early version of the English Attack. White plays g4 before Be3 and exploits the specific structure with ...e6. Move order determines whether the advance is strong, premature, or tactically unsound.