Modern Pterodactyl

The Modern Pterodactyl, the starting point of what is usually called the Pterodactyl Defense, arises when Black meets 3. Nc3 with 3...c5 instead of the customary 3...d6. Black still holds back ...Nf6 and contests d4 at once with the c-pawn, supported by the g7-bishop, whose diagonal runs through d4 toward c3 and the queenside. Typical follow-ups are ...Qa5 and ...Nc6, adding pressure on the queenside and against the c3-knight, and the resulting play is usually unbalanced.

White has several ways to react. 4. Be3, the most frequent choice, maintains the tension and leads to the Eastern, Anhanguera branch; 4. d5 claims space and gives a Benoni-type structure, also filed under the Eastern branch; 4. Nf3 is a plain developing move. Capturing with 4. dxc5 produces the best practical results for White, yet after 4...Bxc3+ 5. bxc3 the White queenside pawns are doubled, and both c3 and c5 then require defense. Engines consider White clearly better, although results in online play are nearly even.