ECO chess code A4 - Queen Pawn Games
A40 - Queen Pawn 
1. d4

A41      
1. d4 d6

A42 - Modern Defence, Averbakh Variation 
1. d4 d6   
2. c4 g6   
3. Nc3 Bg7   
4. e4

A43 - Benoni 
1. d4 c5

A44      
1. d4 c5   
2. d5 e5

A45 - Indian systems 
1. d4 Nf6

A46      
1. d4 Nf6   
2. Nf3

A47 
1. d4 Nf6   
2. Nf3 b6

A48 
1. d4 Nf6   
2. Nf3 g6

A49 
1. d4 Nf6   
2. Nf3 g6   
3. g3

ECO Chess Codes

Chess Openings