The Classical Defense, Main Line is a variation of the Queen's Gambit Accepted, catalogued as ECO D27. The line runs 1. d4 d5 2. c4 dxc4 3. Nf3 Nf6 4. e3 e6 5. Bxc4 c5 6. O-O a6, reaching the position shown below after 12 half-moves.
White holds the centre with pawns on d4, and one pawn capture is available, so the structure has not settled yet. Development is level at two minor pieces each. It is White to move after six moves. White has castled while Black’s king is still uncommitted.
On the Queen's Gambit Accepted generally: Black accepts the gambit pawn but usually cannot hold it. Leads to active play for both sides.
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The Classical Defense, Main Line goes 1. d4 d5 2. c4 dxc4 3. Nf3 Nf6 4. e3 e6 5. Bxc4 c5 6. O-O a6. It is a variation of the Queen's Gambit Accepted and is catalogued as ECO D27.
The Classical Defense, Main Line is ECO D27. ECO codes group openings by their move order, so nearby codes cover closely related lines of the Queen's Gambit Accepted.
Stockfish evaluates the position after 1. d4 d5 2. c4 dxc4 3. Nf3 Nf6 4. e3 e6 5. Bxc4 c5 6. O-O a6 at +0.35 at depth 18, which is a slight pull for White, within normal opening margins. Engine evaluation is only a starting point — at club level the practical value of a line is mostly about whether you know its plans better than your opponent does.
White holds the centre with pawns on d4, and one pawn capture is available, so the structure has not settled yet. Development is level at two minor pieces each. It is White to move. White has castled while Black’s king is still uncommitted.