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

ECO
C10

ECO
C11

ECO
C12

ECO
C13

ECO
C14

1. e4 e6 2. d4 d5
3. Nc3 Nf6

1. e4 e6 2. d4 d5
3. Nc3 Nf6 4. Bg5

1. e4 e6 2. d4 d5
3. Nc3 Nf6
4. Bg5 de4

1. e4 e6 2. d4 d5
3. Nc3 Nf6
4. Bg5 Be7

without 3... Nf6,
3... Bb4

without 4. Bg5

without 4... de4, 4... Be7

ECO
C15

ECO
C16

ECO
C17

ECO
C18

ECO
C19

1. e4 e6 2. d4 d5
3. Nc3 Bb4
4. e5

1. e4 e6 2. d4 d5
3. Nc3 Bb4
4. e5 c5

1. e4 e6 2. d4 d5
3. Nc3 Bb4
4. e5 c5 5. a3

1. e4 e6 2. d4 d5
3. Nc3 Bb4
4. e5 c5

without 4. e5

without 4... c5

without 5. a3

without 5... Bc3

5. a3 Bc3
6. bc3 Ne7

5... Bc3 6. bc3 without 6... Ne7

7. Nf3

6... Ne7 without
7. Nf3, 7. a4

7. a4