ENCYCLOPAEDIA OF CHESS OPENINGS
»ECO Code« is a trademark of Chess Informant Inc.

ECO
A0

ECO
A1

ECO
A2

ECO
A3

ECO
A4

without 1... e5,
1... c5

1. c4 e5

1. c4 c5

1. d4

without 1... Nf6,
1... f5,
1... d5

1... Nf6 without
2. c4

ECO
A5

ECO
A6

ECO
A7

ECO
A8

ECO
A9

1. d4 Nf6 2. c4 c5
3. d5 e6

1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 ed5

1. d4 f5

1. d4 f5 2. c4 Nf6 3. g3 e6

without 2... c5,
2... e6, 2... g6

without 4. Nc3

5. cd5 d6 6. e4 g6 7. Nf3

without 2. c4

2... c5
without 3. d5

4. Nc3 without
4... ed5

2. c4 without
2... Nf6

3. d5 without
3... e6

4... ed5 without
5. cd5

5. cd5 without
5... d6

5... d6 without
6. e4

6. e4 without
6... g6

6... g6 without
7. Nf3