ECO A42

ECO A00–A99 — Flank openings: 1.c4, 1.Nf3, 1.f4 and other first moves, plus early Indian and Benoni systems.

6 named opening lines are classified under ECO code A42.

• Modern Defense: Averbakh System — 1.d4 g6 2.c4 Bg7 3.Nc3 d6 4.e4
• Modern Defense: Averbakh Variation, Pseudo-Sämisch — 1.d4 g6 2.c4 Bg7 3.e4 d6 4.Be3 Nf6 5.f3
• Modern Defense: Kotov Variation — 1.d4 g6 2.c4 Bg7 3.Nc3 d6 4.e4 Nc6
• Modern Defense: Randspringer Variation — 1.d4 g6 2.c4 Bg7 3.Nc3 d6 4.e4 f5
• Pterodactyl Defense — 1.Nf3 c5 2.c4 g6 3.d4 Bg7 4.e4 Qa5+ 5.Nc3 d6
• Pterodactyl Defense: Central, Bogolubovia — 1.d4 g6 2.c4 Bg7 3.e4 d6 4.Nc3 c5 5.Nge2 Qa5