2...e6 turns down the pawn and holds d5 with a second one. The cost is the bishop on c8, which now sits behind its own pawns, and the whole opening is about what Black does with it: free it, trade it, or prove it has a job where it stands. In exchange Black gets a position that has been played by every world champion in history and is relatively immune to opening theory going out of date. This course teaches one setup, ...Nf6, ...Be7, ...0-0, ...Nbd7 and ...c6, against everything White tries, because mastering a few schemes beats memorising a different one for each branch. The most common thing you will meet is the Exchange Variation and the minority attack behind it, so that is where the course starts.
...Nf6, ...Be7, ...0-0, ...Nbd7 and ...c6 is a legal, sound answer to every system White has here. Play it first and learn the finesses afterwards, because a vast array of different set-ups and plans is impractical for anyone with a life outside chess. What changes between chapters is usually one move, and that move is the lesson.
Answer the minority attack before it starts
In the Exchange structure White marches b2-b4-b5 to leave you a weak pawn on c6. The counter is not to defend it. Put the bishop on e6 and the rook on c8, and when b5 comes, push past with ...c5 instead. Then the pawn White was attacking is gone, the file is yours, and the d4-square White gains is the price you pay for it.
Take on c4 only when it wins a move
...dxc4 gives up the centre, so it needs paying for. The payment is a tempo: wait until White's bishop has gone to d3, then take, and the bishop has to move a second time to recapture. Play it a move early and you have surrendered the centre for nothing.
The dark-squared bishops are the trade you want
White's bishop on g5 or h4 is the piece doing the pressing, and your bishop on e7 is the piece doing the least. Every scheme in this course has a way to swap them: ...Ne4 offers the trade in the middle, ...Nh5 takes away the f4-retreat so the trade has to happen, and when White plays Bxf6 the bishop pair comes back the other way. A cramped side gets easier to play with every pair off the board.
II
The lines, chapter by chapter
Learning order, one scoresheet per chapter. The coach serves review one line a day; enter any line directly when you want it now.
The Exchange Variation, and the Attack Behind It
4.cxd5 exd5 fixes the pawns: White has a majority in the centre, Black has one on the queenside, and White's standard plan is b2-b4-b5 against the pawn on c6. Five lines here, one for each of White's serious eleventh moves, plus the trap that catches White players who have not read this far.
4.Bg5 was the main move of the twentieth century and it still is at club level. Black plays ...Be7 and ...h6, which forces White to decide: trade the bishop for the knight, or retreat to h4 and keep the pin. Both answers here run on the same idea, which is to take on c4 the move after White's bishop reaches d3.
The Harrwitz Attack with 5.Bf4 is the one to know, because it is designed against the trades this repertoire wants. After that come the early exchange on d5, the fianchetto, and the quiet 3.e3, all of which the standard setup answers with almost no extra work.
Club games that started in the Queen's Gambit Declined produced these tactics, and you solve every one from Black's side, the seat you actually sit in. Difficulty follows your solving, the same as the puzzle room.
The Queen's Gambit Declined is the chess opening that begins 1.d4 d5 2.c4 e6, and it is filed under ECO D30-D69. This course teaches it from Black's side in 12 drills across 3 chapters, with a coach note on the moves that need one, every position checked with Stockfish at depth 20, and every plan credited to the author who wrote it down.
Lines you will drill
The modern main line against 11.h3
The Elephant Trap against 6.Nxd5?
Holding the pawns back with ...a5 against 11.Rab1
Against the central break against 11.Rae1
Against the Stonewall plan against 11.Ne5
When the knight goes to e2 against 9.Nge2 and f3
When White gives up the bishop against 7.Bxf6
When the bishop retreats against 7.Bh4
Hitting back with ...c5 against 5.Bf4, the Harrwitz Attack
The early exchange against 3.cxd5
Against the fianchetto against 3.g3
Against the quiet line against 3.e3
Theory credited to
The Queen's Gambit Declined: Move by Move, GM Nigel Davies
The Modernized Nimzo: Queen's Gambit Declined Systems, GM Milos Pavlovic
Wikipedia: Queen's Gambit Declined
lichess-org/chess-openings
7 branches are deliberately not drilled here, and the course records which and why rather than leaving the gap silent.
Questions
What is the Queen's Gambit Declined?
The Queen's Gambit Declined is the chess opening that begins 1.d4 d5 2.c4 e6, filed under ECO D30-D69. One setup against everything, and the pawn takes on c4 when it gains a move. The cost is the bishop on c8, which now sits behind its own pawns, and the whole opening is about what Black does with it: free it, trade it, or prove it has a job where it stands.
How do you learn the Queen's Gambit Declined?
This course splits it into 12 drills across 3 chapters. You play each line from Black's side against a coach note that explains the move, then the same lines come back on a spaced-repetition schedule until you can play them without prompting. Every position is verified with Stockfish at depth 20 before it ships.
What does White play against the Queen's Gambit Declined?
The course answers every major reply: Nc3, Nf3, cxd5, g3, e3. Each one has its own drill or a documented transposition into another, and the branches that are not drilled are listed with the reason.
Where does the theory in this Queen's Gambit Declined course come from?
From published work by GM Nigel Davies, GM Milos Pavlovic and the reference sources credited on this page. The engine verifies the moves; the plans and assessments belong to the authors, and every drill records the page or section it came from.