The Modern Variation, Knight Defense is a variation of the Queen's Gambit Declined, catalogued as ECO D51. The line runs 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 Nbd7 5. e3, reaching the position shown below after 9 half-moves.
Both sides have pawns in the centre (White on d4, Black on d5), and one pawn capture is available, so the structure has not settled yet. Development is level at two minor pieces each. It is Black to move after five moves.
On the Queen's Gambit Declined generally: A solid and respected response to the Queen's Gambit. Black maintains a strong central presence.
You can play through this variation move by move in your browser — Learn mode walks the line with an explanation at each step, and Drill mode replays it from memory so you find out whether you actually know it. No account is required.
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The Modern Variation, Knight Defense goes 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 Nbd7 5. e3. It is a variation of the Queen's Gambit Declined and is catalogued as ECO D51.
The Modern Variation, Knight Defense is ECO D51. ECO codes group openings by their move order, so nearby codes cover closely related lines of the Queen's Gambit Declined.
Stockfish evaluates the position after 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 Nbd7 5. e3 at +0.23 at depth 18, which is balanced. 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.
Both sides have pawns in the centre (White on d4, Black on d5), and one pawn capture is available, so the structure has not settled yet. Development is level at two minor pieces each. It is Black to move.