ECO C66
7 named openings and variations are classified as C66. ECO (Encyclopaedia of Chess Openings) codes group openings from A00 to E99 by their opening moves.
- Ruy Lopez: Berlin Defense, Closed Bernstein VariationC661. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O d6 5. d4 Bd7 6. Nc3 Be7 7. Bg5
- Ruy Lopez: Berlin Defense, Closed Showalter VariationC661. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O d6 5. d4 Bd7 6. Nc3 Be7 7. Bxc6
- Ruy Lopez: Berlin Defense, Closed Wolf VariationC661. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O d6 5. d4 Bd7 6. Nc3 exd4
- Ruy Lopez: Berlin Defense, Hedgehog VariationC661. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O d6 5. d4 Bd7 6. Nc3 Be7
- Ruy Lopez: Berlin Defense, Improved Steinitz DefenseC661. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O d6
- Ruy Lopez: Berlin Defense, Tarrasch TrapC661. e4 e5 2. Nf3 Nc6 3. Bb5 d6 4. d4 Bd7 5. Nc3 Nf6 6. O-O Be7 7. Re1 O-O
- Ruy Lopez: Closed Berlin Defense, Chigorin VariationC661. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O d6 5. d4 Nd7