ECO C21
16 named openings and variations are classified as C21. ECO (Encyclopaedia of Chess Openings) codes group openings from A00 to E99 by their opening moves.
- Center Game AcceptedC211. e4 e5 2. d4 exd4
- Center Game: Halasz-McDonnell GambitC211. e4 e5 2. d4 exd4 3. f4
- Center Game: Halasz-McDonnell Gambit, Crocodile VariationC211. e4 e5 2. d4 exd4 3. f4 Bc5 4. Nf3 Nc6 5. c3
- Center Game: Kieseritzky VariationC211. e4 e5 2. d4 exd4 3. Nf3
- Center Game: Lanc-Arnold GambitC211. e4 e5 2. d4 exd4 3. Nf3 Bc5 4. c3
- Center Game: Lanc-Arnold Gambit, Schippler GambitC211. e4 e5 2. d4 exd4 3. Nf3 Bc5 4. c3 dxc3 5. Bc4
- Center Game: Ross GambitC211. e4 e5 2. d4 exd4 3. Bd3
- Center Game: von der Lasa GambitC211. e4 e5 2. d4 exd4 3. Bc4
- Danish GambitC211. e4 e5 2. d4 exd4 3. c3
- Danish Gambit AcceptedC211. e4 e5 2. d4 exd4 3. c3 dxc3
- Danish Gambit Accepted: Chigorin DefenseC211. e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4 cxb2 5. Bxb2 Qe7
- Danish Gambit Accepted: Classical DefenseC211. e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4 cxb2 5. Bxb2 Nf6
- Danish Gambit Accepted: Copenhagen DefenseC211. e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4 cxb2 5. Bxb2 Bb4+
- Danish Gambit Accepted: Schlechter DefenseC211. e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4 cxb2 5. Bxb2 d5
- Danish Gambit Accepted: Svenonius DefenseC211. e4 e5 2. d4 exd4 3. c3 Ne7
- Danish Gambit Declined: Sörensen DefenseC211. e4 e5 2. d4 exd4 3. c3 d5