ECO A40 · Pterodactyl Defense

Pterodactyl Defense: Queen Pterodactyl, Quiet Line

1. d4 g6 2. c4 Bg7 3. Nc3 c5 4. e3

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Black to move. The arrow shows Stockfish’s best move.
Best move

4… Nf6+0.35

White is slightly better. Stockfish 18, depth 18.

Analyze this position

In the Pterodactyl Defense: Queen Pterodactyl, Quiet Line (A40), reached after 1. d4 g6 2. c4 Bg7 3. Nc3 c5 4. e3, Stockfish 18 recommends 4… Nf6 for Black. White is slightly better (+0.35).

Top engine moves

  1. +0.354… Nf6 5. d5 e6 6. Nf3 O-O 7. Be2 d6 8. e4 exd5 9. exd5
  2. +0.374… cxd4 5. exd4 Nf6 6. d5 O-O 7. Nf3 e6 8. Be2 exd5 9. cxd5
  3. +0.464… d6 5. Be2 Nf6 6. Nf3 O-O 7. O-O cxd4 8. exd4 d5 9. h3

Frequently asked questions

What is the best move in the Pterodactyl Defense: Queen Pterodactyl, Quiet Line?
After 1. d4 g6 2. c4 Bg7 3. Nc3 c5 4. e3, Stockfish 18 at depth 18 recommends 4… Nf6 for Black, continuing 5. d5 e6 6. Nf3 O-O 7. Be2 d6 8. e4 exd5 9. exd5. White is slightly better (+0.35). The next best moves are 4… cxd4 (+0.37) and 4… d6 (+0.46).
Is the Pterodactyl Defense: Queen Pterodactyl, Quiet Line a good opening?
Stockfish rates the position at +0.35: white is slightly better. Evaluations this early in the game are small, so practical results depend far more on knowing the plans and typical structures than on the engine's number.
What is the ECO code of the Pterodactyl Defense: Queen Pterodactyl, Quiet Line?
A40. ECO codes classify chess openings from A00 to E99; A is the volume for flank openings.

Opening names from the Lichess opening book (CC0). Pieces by Colin M.L. Burnett (GPLv2+).