Semi-Averbakh Variation, Pterodactyl Variation Declined

This line arises from the Semi-Averbakh setup, in which White plays c2-c4 before developing the queen's knight. Black hits the center at once with 3...c5. White neither captures on c5 nor advances with d4-d5, and develops with 4. Nf3 and 5. Be2. Black then plays 5...Qa5+, a queen check typical of Pterodactyl setups. Black's pressure falls on d4 and the dark squares along the long diagonal and the a5-e1 line.