Chess Openings Lab
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Queen's Gambit Declined: Been-Koomen Variation

The Been-Koomen Variation is 4...c5 against the Queen's Gambit Declined after 4.Bg5, striking at d4 before White plays Nf3. White wants to open lines and exploit the pin, while Black accepts a likely isolated queen pawn for free piece play.

Moves
1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 c5
ECO
D50
Engine
+0.18 · level (Stockfish 17.1, depth 20)
Played
170 games in our lichess sample
White scores
54.4%

Key ideas for both sides

White

  • 5.cxd5 cxd4 6.Qxd4 brings the queen to the center early, since the c3 knight is defended and no knight can hit it yet.
  • Push e4 in the top line to break up Black's center and give White an open, active game.
  • Bxf6 gives up the bishop to wreck Black's control of d5 and e4.
  • With e3 and exd4 White gets a symmetrical IQP for both sides and quick Rc1.

Black

  • ...cxd4 is the point: Black trades a wing pawn for White's center pawn.
  • Develop with ...Be7, ...Nc6 and ...O-O; the c8 bishop has open diagonals after ...exd5.
  • After Nf3 and Nxd4, ...Qb6 hits b2, which lost its defender when the bishop left c1.
  • Accept an isolated d5 pawn if it brings active pieces and pressure on the c-file.

Plans and pawn structure

Most lines leave an isolated pawn on d5, for Black or both sides. White blockades d4 or d5 with knights, trades minor pieces and targets the lone pawn in an ending. Black wants piece activity: knights on c6 and e4, rooks on c8 and d8, and the threat of ...d4 to open lines. If White's queen comes to d4 early, Black gains time by hitting it with ...Nc6.

Where the engine's main line heads: Black has an isolated queen pawn. Black has an isolated d-pawn: nothing on the c- or e-file to support it.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.18: level. Its three top choices for White:

  1. +0.18 5.cxd5 cxd4 6.Qxd4 Be7 7.e4 exd5
  2. +0.05 5.Nf3 cxd4 6.Nxd4 Qb6 7.cxd5 Nxd5
  3. −0.10 5.e3 cxd4 6.exd4 Be7 7.Nf3 O-O

Pawns, from White's side.

How it scores on lichess

170 rated lichess games reached this position; White scored 54.4%.

1200–159955.8%
1600–199953.1%

Light: White wins. Grey: draws. Dark: Black wins. About the sample.

Where it goes next

  • Pseudo-Tarrasch Variation, Canal Variation5.cxd5 · rare
  • Semi-Tarrasch Defense, Krause Variation5.Nf3 · rare

How to play against it

As White, open the game with 5.cxd5 and recapture on d4 with the queen. Then e4 hits the center before Black is castled. As Black, after Nf3 and Nxd4, the ...Qb6 idea is the quickest way to punish the missing c1 bishop.

Questions

What are the moves of the Queen's Gambit Declined: Been-Koomen Variation?

The Queen's Gambit Declined: Been-Koomen Variation starts 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 c5. Its ECO code is D50.

Is the Queen's Gambit Declined: Been-Koomen Variation good for Black?

Stockfish 17.1 rates the position +0.18 at depth 20, which is level. Best for Black players who like open positions and IQP middlegames; it demands active, accurate piece play.

What is the main idea of the Queen's Gambit Declined: Been-Koomen Variation?

Black ignores the pin and strikes at d4 with ...c5, aiming for open lines. White answers with cxd5 and central play, often leaving Black with an isolated d5 pawn and active pieces.

What should White play next?

The engine's first choice is cxd5, with Nf3 and e3 close behind. 5.cxd5 releases the center first, so after ...cxd4 the queen can recapture and hit the f6 knight's support.

Updated October 2026. Sources and method.