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

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.

Practise the line

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

Your move 1 of 30/3

1.d4d5
2.Nf3Nf6
3.e3

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

Common mistakes

Three that come up again and again below master level. Each is ordinary opening theory — a named trap, or the error every coach corrects — not a statistic, and not drawn from anybody's games.

Breaking with e4 before the pieces are on their squares

1.d4 d5 2.Nf3 Nf6 3.e3 e6 4.Bd3 c5 5.c3 Nc6 6.e4

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: 6.e4 opens the centre against an uncastled king and loses time: Black takes twice and White's loose pawns have to be defended by the pieces that were meant to be attacking.
Instead: Nbd2, O-O and Re1 first. The Colle's break is worth waiting four moves for; played early it is a pawn trade that helps Black develop.

Playing the system against a free bishop

1.d4 d5 2.Nf3 Nf6 3.e3 Bf5

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

1.d4 d5 2.Nf3 Nf6 3.e3 e6 4.Bd3 c5 5.c3 Nc6 6.O-O Qb6 7.b3

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.

Try it on one of your own

The board above is for the line itself; this is for a game you played. Paste a game in this opening, or pull one from chess.com, and every move is graded against what the engine would have played. Open the board, read how the grading works, or go back to the other openings.