Caissa Codex
D05

Queen's Pawn Game: Colle System trainer

Back to the opening, all openings to practise or my repertoire

Type a move and press Enter: e4, Nf3, O-O, or from and to squares like g1f3 (e7e8q to promote). The board is also played with the mouse.

Practise the Queen's Pawn Game: Colle System

Play Black's moves of the line from memory — 1. d4 Nf6 2. Nf3 e6 3. e3 b6 4. Bd3 Bb7 5. O-O c5 6. b3 Be7 7. Bb2 O-O 8. Nbd2 d5 — and the trainer plays White's replies; "Play the other side" turns it around.

Read about the line, its statistics on Lichess and Stockfish's evaluation on the Queen's Pawn Game: Colle System page, or pick another opening in the opening trainer.

https://chesscodex.org/train/queens-pawn-game-colle-system-4