Classical Variation, Quiet System

The Quiet System is the most popular way to handle the Classical Variation. With 5. Be2, White places the light-squared bishop on an unambitious but useful square. It clears the way for kingside castling and covers f3, so a later ...Bg4 pin can be met by recapturing with the bishop without spoiling the pawns. White does not commit to f2-f4 or a queenside castling plan, and keeps the d4-e4 center intact. Black castles in about four games out of five, and 6. O-O normally follows.

Black's main choices at move six have their own names. The Chigorin Line, 6...Nc6, develops quickly and pressures d4 in preparation for ...e5. The Parma Defense, 6...Bg4, pins the f3-knight and aims to weaken White's grip on d4 by exchanging it. The Czech Defense, 6...c6, keeps the position flexible and prepares queenside expansion. Black can also deviate before castling with 5...Bg4 or 5...c6, and engines rate 5...a6 as a reasonable option. Results in practice are close to even, and engines see a slight edge for White.