Chess Openings Lab
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Queen's Gambit Declined: Three Knights Variation

The Three Knights Variation is 4.Nc3 after 1.d4 Nf6 2.c4 e6 3.Nf3 d5, putting three knights out and leaving Black to choose a system. Black can pin with ...Bb4, play the classical ...Be7, strike with ...c5, or take on c4 with ...dxc4.

Moves
1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3
ECO
D37
Engine
+0.20 · level (Stockfish 17.1, depth 20)
Played
3,642 games in our lichess sample
White scores
54.1%

Key ideas for both sides

White

  • Against ...Bb4, Bg5 pins back, and after ...h6 Bxf6 the queen check Qa4+ forces ...Nc6.
  • Against ...Be7, Bf4 avoids ...h6 and ...Ne4 trades and aims at c7 with Rc1.
  • Against ...c5, cxd5 and Qxd4 with e4 open the center while White is ahead in development.
  • Against ...Nbd7 or ...c6, choose between Bg5 and an early e3 depending on your repertoire.

Black

  • 4...Bb4 is the Ragozin: it pins the c3 knight and can double White's pawns.
  • 4...Be7 keeps things quiet and leads to the Orthodox, Tartakower or Lasker systems.
  • 4...c5 is the Semi-Tarrasch, hitting d4 and preparing a knight recapture on d5.
  • ...dxc4 gives the Vienna, a sharp choice where Black grabs a pawn and hits back with ...c5.

Plans and pawn structure

This is a crossroads where Black picks the pawn structure. With ...Be7, Black aims for ...O-O and a later ...c5 or ...dxc4, while White plays Bg5 or Bf4 and Rc1. With ...Bb4, the game takes on a Nimzo-Indian flavor, and Black may trade on c3 to damage White's pawns. With ...c5 or ...dxc4, the center opens early and development counts more than structure.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.20: level. Its three top choices for Black:

  1. +0.20 4...Bb4 5.Bg5 h6 6.Bxf6 Qxf6 7.Qa4+
  2. +0.26 4...Be7 5.Bf4 O-O 6.e3 b6 7.Rc1
  3. +0.27 4...c5 5.cxd5 cxd4 6.Qxd4 exd5 7.e4

Pawns, from White's side.

How it scores on lichess

3,642 rated lichess games reached this position; White scored 54.1%.

under 120046.8%
1200–159958.6%
1600–199953.8%
2000 and up53.3%

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

Where it goes next

How to play against it

As Black, pick one system and learn its main plans: ...Be7 for quiet development, ...Bb4 for active piece play, or ...c5 for open lines. Avoid passive setups like ...Nbd7 with ...c6 if you do not know the Semi-Slav lines that can follow.

Other lines with this name

The lichess opening list also files this line under the same name, though it reaches a different position: 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 Be7 5.e3 O-O.

Questions

What are the moves of the Queen's Gambit Declined: Three Knights Variation?

The Queen's Gambit Declined: Three Knights Variation starts 1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3. Its ECO code is D37.

Is the Queen's Gambit Declined: Three Knights Variation good for White?

Stockfish 17.1 rates the position +0.20 at depth 20, which is level. In 3,642 lichess games from our sample, White scored 54.1%. A flexible main line for White; Black has many sound replies and should pick the one that fits their style.

What is the main idea of the Queen's Gambit Declined: Three Knights Variation?

White develops the third knight and asks Black to choose a system. Black's main choices are ...Bb4 for the Ragozin, ...Be7 for classical play, ...c5 for the Semi-Tarrasch, and ...dxc4 for the Vienna.

What should Black play next?

The engine's first choice is Bb4, with Be7 and c5 close behind. 4...Bb4 pins the c3 knight and fights for e4, leading to the Ragozin Defense.

Updated October 2026. Sources and method.