Colle System: ...c5, ...Bd6 and ...Qc7 is variation 2 of 5 in the Beating 1.d4 Sidelines course, a intermediate opening course for Black (ECO D05). It runs 26 moves and begins 1. d4 d5 2. Nf3 Nf6 3. e3 e6 4. Bd3 c5 …. Black copies White's harmonious set-up but adds ...c5. When White prepares the e4 break, Black puts the queen and bishop on the b8-h2 diagonal and meets e4 with active piece play. In the lesson every move is explained on a board and then drilled; it is free.
Move by move
1. d4 – White takes the centre.
1... d5 – Black meets the centre with a pawn of his own.
2. Nf3 – Develops and controls e5; White keeps his options open.
2... Nf6 – Black develops the knight and stops e4 for now.
3. e3 – The Colle: White locks in the c1 bishop on purpose, planning Bd3, Nbd2 and the e4 break.
3... e6 – Black prepares ...c5 and ...Bd6, mirroring White's natural development.
4. Bd3 – The bishop aims at h7 and supports e4.
4... c5 – Hits d4 at once, so White must spend a tempo on c3 or allow ...cxd4 with a free hand on the c-file.
5. c3 – White supports d4 with a pawn; this is the classical Colle-Koltanowski.
5... Nc6 – Another piece on d4 and natural development.
6. Nbd2 – The knight supports e4, which is White's main plan.
6... Bd6 – Black's bishop takes the b8-h2 diagonal and controls e5, the square White's pawn would like to use after e4-e5.
7. O-O – White castles before opening the centre.
7... O-O – Black follows suit; both kings are safe.
8. dxc5 – White releases the tension to prepare e4 with the bishop gone from d6.
8... Bxc5 – Black recaptures and his bishop now points at f2 and e3.
The lesson goes on for 10 more moves, each with its explanation.
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