ECO A40. A chess opening with 34 known variations.
The variations below diverge from the first move, so each has its own page with the full move order, the position it reaches, and a Stockfish evaluation.
All 17 lines can be practised free in the browser: pick a variation, walk it move by move in Learn mode, then drill it from memory until you can play it without prompting.
The Pterodactyl Defense is catalogued under ECO codes A40–B27. Individual variations list their own specific code on their page.
How can I practise the Pterodactyl Defense for free?
Open any variation on Chess Ramp and use Learn mode to walk the line one move at a time, then Drill mode to replay it from memory. Practice runs in your browser with no account required.