Openings · D04–D05

Colle System

A set-up rather than a variation: d4, Nf3, e3, Bd3, c3, Nbd2, and then the e4 break all of it was built for.

1.d4 d5 2.Nf3 Nf6 3.e3played as White

Play it through on the board below.

Practise the line

You play White; the other side answers on its own. Nothing here is saved or graded.

8
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a1
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Your move 1 of 30/3
  1. 1.d4d5
  2. 2.Nf3Nf6
  3. 3.e3

Your move. Drag a piece, or tap it and then its square.

The idea

Every piece has a square decided in advance, which is what makes it a system: the same six moves against almost anything, and no theory to forget. The pay-off is the break e3–e4, which opens the position at the moment Black's pieces are least ready for it.

The famous attack is the one that follows: bishop on d3, knight to e5, queen to e2, rook to e1, all pointing at h7. It works because Black's light-squared bishop is so often stuck behind a pawn on e6 — which is also the clue to when the Colle is the wrong choice.

Common mistakes

Three that come up again and again below master level: named traps and the errors every coach corrects.

Breaking with e4 before the pieces are on their squares

After 6.e4
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
The mistake
Playing the break as soon as it is legal, with the knight still on b1 and the king still in the middle.
Why it costs
Here it loses a piece. 6…dxe4 attacks the bishop on d3 and the knight on f3 at once, and one of them goes; the engine rates it winning for Black. With the knight on d2 the pawn could be taken back, which is the whole reason the Colle waits for Nbd2.
Instead
Nbd2, O-O and Re1 first. The Colle's break is worth waiting four moves for; played early it can cost a piece, and at best it is a pawn trade that helps Black develop.

Playing the system against a free bishop

After 3…Bf5
  1. 1.
  2. 2.
  3. 3.
The mistake
Shutting your own bishop in with e3 when Black's has already left the back rank.
Why it costs
The whole attack assumes Black's light-squared bishop is buried behind an e6 pawn. Against …Bf5 or …Bg4 it is not, so White has a passive bishop on d3 with nothing to hit and Black has the freer game.
Instead
Meet an early …Bf5 with c4, or with Bd3 offering the trade and then Qb3 hitting b7 and d5. Against a fianchetto, the Colle–Zukertort — b3 and Bb2 — is the version that still has a plan.

Meeting ...Qb6 with a pawn move

After 7.b3
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
The mistake
Defending b2 with 7.b3, which is the move …Qb6 was played to provoke.
Why it costs
The pawn on b3 takes the square the knight wants, weakens c3 permanently and gives Black's queen something to aim at for the rest of the game. Black continues …c4 or …Be7 and White's queenside is already the worse half of the board.
Instead
7.Qe2 or 7.Qc2, defending along the rank, or simply 7.Nbd2 and letting the b2 pawn go if Black really wants to spend three moves on it.

What the engine says

After 1.d4 d5 2.Nf3 Nf6 3.e3, these are Black's six best moves according to Stockfish, with the bar showing Black's chance of winning. The whole list sits within 2 percentage points of win chance: none of them is a mistake, and the choice is about the positions you want to play.

  1. c5+0.2
  2. e6+0.2
  3. a6+0.2
  4. b6+0.2
  5. Nbd7+0.3
  6. Bf5+0.3

The engine's main line from c5: c5 c4 e6 Nc3 Nc6 a3 a6 dxc5.

Stockfish 18, depth 24. Scores are in pawns from White's side. Another engine or depth will move individual numbers a little; the picture does not change. How we check.

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