Modern Defense: Semi-Averbakh Variation, Pterodactyl Variation Accepted

An entry in the Encyclopedia of Chess Openings (ECO A04), reached after 10 half-moves: 1. Nf3 g6 2. d4 Bg7 3. e4 d6 4. c4 c5 5. dxc5 Qa5+.

Black rook — Use ← → arrows or click moves to step through.

Black knight — Use ← → arrows or click moves to step through.

End of this line

No further variations branch from this position in our database. To explore neighbouring ideas:

⤴ See the Modern Defense family overview

About this opening

Modern Defense: Semi-Averbakh Variation, Pterodactyl Variation Accepted is an opening in the Encyclopedia of Chess Openings, classified under code A04. ECO group A (A00–A99) covers flank and irregular openings, including the English, Bird, Réti and Dutch defences. This particular variation is reached after 10 half-moves from the starting position, with the move sequence 1. Nf3 g6 2. d4 Bg7 3. e4 d6 4. c4 c5 5. dxc5 Qa5+.

It belongs to the Modern Defense family. Within that family this is a level-2 branch (the Semi-Averbakh Variation → Pterodactyl Variation Accepted line).

The opening sequence in prose form: 1.Nf3 g6, 2.d4 Bg7, 3.e4 d6, 4.c4 c5, 5.dxc5 Qa5+. From this position the encyclopaedia records no further canonical continuations — practical play branches into unnamed transpositions or returns to the parent line for alternative ideas.