Caissa Codex
B06

Pterodactyl Defense: Fianchetto, King Pterodactyl

Chess diagram: Pterodactyl Defense: Fianchetto, King Pterodactyl after 4…Qa5+

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Statistics from Lichess

25 games: White 60.0% / Draw 4.0% / Black 36.0%

The moves played next. Pick one to see it on the board.
Next moveGamesWhite / Draw / BlackW / D / B
1515
66
22
22

Rated Lichess games between players rated 1600 to 2500, from the Lichess opening explorer, updated Oct 30, 2026

Engine evaluation

+0.12 The position is about equal

Best play: 5. Bd2 Qb6 6. Bc3 cxd4 7. Bxd4 Bxd4 8. Qxd4 Qxd4 9. Nxd4 Nc6

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

Overview

Pterodactyl Defense: Fianchetto, King Pterodactyl (ECO B06, Semi-Open Games) is a variation of the Modern Defense, reached after 1. e4 g6 2. d4 Bg7 3. g3 c5 4. Nf3 Qa5+ (4 moves).

In 25 rated Lichess games between players rated 1600 to 2500, White won 60.0%, Black 36.0% and 4.0% were drawn. White's most played move here is 5. c3, in 60% 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 3. g3 c5 4. Nf3 Qa5+, the position after Modern Defense also goes on to:

Cite this page

Caissa Codex. “Pterodactyl Defense: Fianchetto, King Pterodactyl (B06)”. Lichess data as of 30 Oct 2026. https://chesscodex.org/openings/pterodactyl-defense-fianchetto-king-pterodactyl

https://chesscodex.org/openings/pterodactyl-defense-fianchetto-king-pterodactyl