Chess Opening Theory/1. e4/1...e6/2. d4/2...d5/3. Nf3

Perseus gambit 1. e4 e6 2. d4 d5 3. Nf3 C00 French defence 3. Nf3!? · Perseus gambit With 3. Nf3, White gambits their e4 pawn, and after 3...dxe4 must move their knight again. This at first seems like just a plain mistake for White. If White tries to recapture the pawn with 4. Ng5?, they will find they can't bring enough attackers (4...Nf6 5. Nc3 Bb4 6. Bd2 Qxd4 ∓). Instead White plays 4. Ne5, hoping a nice central outpost for their knight is sufficient compensation. This knight is hard for Black to remove: 4...f6?? to kick the knight is a trap, as it allows 5. Qh5+ g6 6. Nxg6 hxg6 7. Qxh8 +-. 4...Nd7, to trade off White's knight, is an option. 4...Nf6 instead is a natural move, leaving White's knight and focusing on protecting e4 and preventing any ideas of Qh5. Black has an edge here, by engine and practically. The Perseus gambit may also arise in the move order 1. e4 e6 2. Nf3 d5 3. d4!?. Theory table 1. e4 e6 2. d4 d5 3. Nf3!? 3 4 5 6 7 Perseus-Carlson gambit ...dxe4 Ne5Nf6 Be3Bd6 Nd2O-O Bg5  ⩱ ...... ...... Nc3Nxe5 dxe5Qxd1+ Kxd1f5 ⩱ ...... ...Ne7 Qh5g6 Qh4Bg7 Qxd4O-O∓ ...... ...... ...... ...Qxd4?? Qf6!  ± ...... ...f6?? Qh5+g6 Nxg6hxg6 Qxh8  +-