C40 — King's Knight Opening
Open Games & French (C00–C99)
1. e4 e5 2. Nf3
Full page: King's Knight Opening →ECO C40 covers King's Knight Opening and related lines (King's Knight Opening, Elephant Gambit, Gunderam Defense, King's Pawn Game: Busch-Gass Gambit). Main line 1. e4 e5 2. Nf3 with variations, statistics, and the best responses.
40 lines under C40
King's Knight Opening
1. e4 e5 2. Nf3
Elephant Gambit
1. e4 e5 2. Nf3 d5
Gunderam Defense
1. e4 e5 2. Nf3 Qe7
King's Pawn Game: Busch-Gass Gambit
1. e4 e5 2. Nf3 Bc5
King's Pawn Game: Damiano Defense
1. e4 e5 2. Nf3 f6
King's Pawn Game: Gunderam Gambit
1. e4 e5 2. Nf3 c6
King's Pawn Game: McConnell Defense
1. e4 e5 2. Nf3 Qf6
Latvian Gambit
1. e4 e5 2. Nf3 f5
Latvian Gambit Accepted
1. e4 e5 2. Nf3 f5 3. exf5
Latvian Gambit: Diepstraten Countergambit
1. e4 e5 2. Nf3 f5 3. c4
Latvian Gambit: Lobster Gambit
1. e4 e5 2. Nf3 f5 3. g4
Latvian Gambit: Mason Countergambit
1. e4 e5 2. Nf3 f5 3. d4
Latvian Gambit: Mayet Attack
1. e4 e5 2. Nf3 f5 3. Bc4
Latvian Gambit: Mlotkowski Variation
1. e4 e5 2. Nf3 f5 3. Nc3
Latvian Gambit: Senechaud Gambit
1. e4 e5 2. Nf3 f5 3. b4
Elephant Gambit: Maróczy Gambit
1. e4 e5 2. Nf3 d5 3. exd5 Bd6
Elephant Gambit: Paulsen Countergambit
1. e4 e5 2. Nf3 d5 3. exd5 e4
King's Pawn Game: Busch-Gass Gambit, Chiodini Gambit
1. e4 e5 2. Nf3 Bc5 3. Nxe5 Nc6
King's Pawn Game: Gunderam Defense, Gunderam Gambit
1. e4 e5 2. Nf3 Qe7 3. Bc4 f5
Latvian Gambit: Fraser Defense
1. e4 e5 2. Nf3 f5 3. Nxe5 Nc6
Latvian Gambit: Greco Variation
1. e4 e5 2. Nf3 f5 3. Nxe5 Qe7
Latvian Gambit: Mayet Attack, Morgado Defense
1. e4 e5 2. Nf3 f5 3. Bc4 Nf6
Latvian Gambit: Mayet Attack, Strautins Gambit
1. e4 e5 2. Nf3 f5 3. Bc4 b5
King's Pawn Game: La Bourdonnais Gambit
1. e4 e5 2. Nf3 Qf6 3. Bc4 Qg6 4. O-O
Latvian Gambit Accepted: Foltys-Leonhardt Variation
1. e4 e5 2. Nf3 f5 3. Nxe5 Qf6 4. Nc4
Latvian Gambit Accepted: Main Line
1. e4 e5 2. Nf3 f5 3. Nxe5 Qf6 4. d4
Elephant Gambit: Wasp Variation
1. e4 e5 2. Nf3 d5 3. Nxe5 dxe4 4. Bc4 Qg5
King's Pawn Game: Damiano Defense, Damiano Gambit, Chigorin Gambit
1. e4 e5 2. Nf3 f6 3. Nxe5 Qe7 4. Nf3 d5
Latvian Gambit: Corkscrew Countergambit
1. e4 e5 2. Nf3 f5 3. Bc4 fxe4 4. Nxe5 Nf6
Latvian Gambit: Mayet Attack, Polerio-Svedenborg Variation
1. e4 e5 2. Nf3 f5 3. Bc4 fxe4 4. Nxe5 d5
Latvian Gambit Accepted: Bilguer Variation
1. e4 e5 2. Nf3 f5 3. Nxe5 Qf6 4. d4 d6 5. Nc4
Latvian Gambit Accepted: Foltys Variation
1. e4 e5 2. Nf3 f5 3. Nxe5 Qf6 4. Nc4 fxe4 5. d3
Latvian Gambit Accepted: Leonhardt Variation
1. e4 e5 2. Nf3 f5 3. Nxe5 Qf6 4. Nc4 fxe4 5. Nc3
Latvian Gambit: Mayet Attack, Poisoned Pawn Variation
1. e4 e5 2. Nf3 f5 3. Bc4 fxe4 4. Nxe5 Qg5 5. d4 Qxg2
King's Pawn Game: Damiano Defense, Damiano Gambit
1. e4 e5 2. Nf3 f6 3. Nxe5 fxe5 4. Qh5+ g6 5. Qxe5+ Qe7 6. Qxh8
Latvian Gambit Accepted: Bronstein Attack
1. e4 e5 2. Nf3 f5 3. Nxe5 Qf6 4. d4 d6 5. Nc4 fxe4 6. Be2
Latvian Gambit Accepted: Nimzowitsch Attack
1. e4 e5 2. Nf3 f5 3. Nxe5 Qf6 4. d4 d6 5. Nc4 fxe4 6. Ne3
Latvian Gambit: Corkscrew Gambit
1. e4 e5 2. Nf3 f5 3. Nxe5 Nf6 4. Bc4 fxe4 5. Nf7 Qe7 6. Nxh8 d5
Latvian Gambit Accepted: Bronstein Gambit
1. e4 e5 2. Nf3 f5 3. Nxe5 Qf6 4. d4 d6 5. Nc4 fxe4 6. Qh5+ g6 7. Qe2
Latvian Gambit: Behting Variation
1. e4 e5 2. Nf3 f5 3. Bc4 fxe4 4. Nxe5 Qg5 5. Nf7 Qxg2 6. Rf1 d5 7. Nxh8 Nf6