ECO code: A29
English Opening: Four Knights, Main Line 6.O-O
Moves: 1. c4 e5 2. Nc3 Nc6 3. Nf3 Nf6 4. g3 Bb4 5. Bg2 O-O 6. O-O
This line of the English Opening features a flexible and harmonious development by White, culminating in castling kingside on move 6. The characteristic of 6.O-O is that it prioritizes king safety and prepares for central and queenside operations without immediate confrontation. White adopts a solid, well-coordinated setup aiming for long-term positional pressure, rather than an immediate tactical assault.
From White’s perspective, this move is primarily defensive in nature—securing the king and completing development—while keeping options open for central or flank play. Black’s setup with ...Bb4 and ...O-O also shows a balance between development and pressure on White’s center and queenside.
The English Opening generally exerts influence on the center indirectly. In this line, White does not immediately occupy the center with pawns but applies pressure on central squares through piece placement and prepares for potential central breaks later. Therefore, this opening does not attack the center immediately but focuses on controlling key squares and maintaining flexibility.
This opening is defined by the position shown on the board below. The moves displayed are a typical sequence that leads to it, but different sequences can reach the same position and still carry the same opening name.
Practice puzzles and train your tactics with real positions from games that used the English: Four Knights, Main Line 6.O-O, and sharpen your opening mastery.
Puzzle 1 of 1 - Move #20 white