Caissa Codex
A40

Colle System: Siroccopteryx Variation

Chess diagram: Colle System: Siroccopteryx Variation after 5…Qa5+

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Statistics from Lichess

41 games: White 53.7% / Draw 0.0% / Black 46.3%

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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 30, 2026

Engine evaluation

+0.19 The position is about equal

Best play: 6. Bd2 Qd8 7. O-O Nc6 8. h3 d5 9. Nxc6 bxc6 10. Nc3 Nf6

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

Overview

Colle System: Siroccopteryx 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 cxd4 5. Nxd4 Qa5+ (5 moves).

In 41 rated Lichess games between players rated 1600 to 2500, White won 53.7%, Black 46.3% and 0.0% were drawn. White's most played move here is 6. c3, in 63% of those games. That is too few games for the percentages to mean much.

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Other lines from the same position

Instead of 2. Nf3 Bg7 3. e3 c5 4. Bd3 cxd4 5. Nxd4 Qa5+, the position after Queen's Pawn Game: Modern Defense also goes on to:

Cite this page

Caissa Codex. “Colle System: Siroccopteryx Variation (A40)”. Lichess data as of 30 Oct 2026. https://chesscodex.org/openings/colle-system-siroccopteryx-variation

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