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

ECO
D20

ECO
D21

ECO
D22

ECO
D23

ECO
D24

1. d4 d5
2. c4 dc4 3. Nf3

1. d4 d5 2. c4 dc4 3. Nf3 a6

1. d4 d5
2. c4 dc4 3. Nf3 Nf6

1. d4 d5 2. c4 dc4 3. Nf3 Nf6 4. Nc3

without 3. Nf3

without 3... a6,
3... Nf6

without 4. Nc3,
4. e3

ECO
D25

ECO
D26

ECO
D27

ECO
D28

ECO
D29

1. d4 d5 2. c4 dc4 3. Nf3 Nf6
4. e3 e6

1. d4 d5
2. c4 dc4 3. Nf3 Nf6 4. e3 e6

1. d4 d5 2. c4 dc4 3. Nf3 Nf6
4. e3 e6

1. d4 d5
2. c4 dc4 3. Nf3 Nf6 4. e3 e6

without 4... e6

without 5. Bc4

5. Bc4 c5 6. 0-0

5. Bc4 c5
6. 0-0 a6 7. Qe2

5. Bc4 c5
6. 0-0 a6
7. Qe2 b5

5. Bc4 without 5... c5

without 6... a6

without 7... b5

5... c5 without
6. 0-0

6... a6 without
7. Qe2