Caissa Codex
D05

Queen's Pawn Game: Colle System, Traditional Colle 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, Traditional Colle

Play White's moves of the line from memory — 1. d4 Nf6 2. Nf3 e6 3. e3 c5 4. Bd3 d5 5. c3 — and the trainer plays Black'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, Traditional Colle page, or pick another opening in the opening trainer.

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