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

ECO
D00

ECO
D01

ECO
D02

ECO
D03

ECO
D04

1. d4 d5 2. Nc3

1. d4 d5 2. Nf3

1. d4 d5
2. Nf3 Nf6 3. Bg5

1. d4 d5
2. Nf3 Nf6 3. e3

without 2. Nc3,
2. Nf3, 2. c4

without 2... Nf6

without 3... e6

2... Nf6 without
3. Bg5, 3. e3

ECO
D05

ECO
D06

ECO
D07

ECO
D08

ECO
D09

1. d4 d5 2. c4

1. d4 d5
2. c4 Nc6

1. d4 d5 2. c4 e5

1. d4 d5 2. c4 e5
3. de5 d4
4. Nf3 Nc6 5. g3

without 2... Nc6, 2... e5, 2... c6,
2... dc4, 2... e6

without 3. de5

3. de5 without
3... d4

3... d4 without
4. Nf3

4. Nf3 without
4... Nc6

4... Nc6 without
5. g3