Caissa Codex
A40

Colle System: Pterodactyl Variation

Chess diagram: Colle System: Pterodactyl Variation after 4…Qa5+

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Statistics from Lichess

174 games: White 51.1% / Draw 5.2% / Black 43.7%

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Next moveGamesWhite / Draw / BlackW / D / B
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Rated Lichess games between players rated 1600 to 2500, from the Lichess opening explorer, updated Oct 19, 2026

Engine evaluation

+0.67 White is slightly better

Best play: 5. Bd2 Qb6 6. Nc3 cxd4 7. exd4 Nf6 8. O-O O-O 9. Re1 e6

Stockfish 19, depth 30, after the line's last move. Scores are in pawns, from White's side.

Overview

Colle System: Pterodactyl Variation (ECO A40, Flank Openings) is a variation of the Queen's Pawn Game: Modern Defense, reached after 1. d4 g6 2. Nf3 Bg7 3. e3 c5 4. Bd3 Qa5+ (4 moves).

In 174 rated Lichess games between players rated 1600 to 2500, White won 51.1%, Black 43.7% and 5.2% were drawn. White's most played move here is 5. c3, in 58% of those games.

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Other lines from the same position

Instead of 2. Nf3 Bg7 3. e3 c5 4. Bd3 Qa5+, the position after Queen's Pawn Game: Modern Defense also goes on to:

Cite this page

Caissa Codex. “Colle System: Pterodactyl Variation (A40)”. Lichess data as of 19 Oct 2026. https://chesscodex.org/openings/colle-system-pterodactyl-variation

https://chesscodex.org/openings/colle-system-pterodactyl-variation