Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. d4/3...exd4/4. Bc4

= Scotch Gambit = Black can continue the Scotch with 4...Bc5 5.c3 and now 5...Nf6 will transpose into a safe variation of the Giuoco Piano. Alternatively, he can transpose into the Two Knights Defense with 4...Nf6 and White has now two sound options: the obvious 5. e5 and 5. O-O. In the first case 5. e5 white goes for maintaining a strong center and an open game with chances for both sides. 5. O-O gives away the pawn, and while taking it might seem risky due to 6.. Re1 it's perfectly sound, and white will only get his pawn back.

Black can instead accept the gambit with 5...dxc3 but this is riskier because White will gain a lead in development. A possible continuation is 6.Nxc3 (Grandmaster Sveshnikov has played 6.Bxf7+!? Kxf7 7.Qd5+ followed by 8.Qxc5 recommended in Chess Openings for White, explained) 6...d6 7.Qb3 Qd7 8.Nd5 Nge7 9.Qc3 0-0.Göring Gambit'. This gambit is quite similar to the Danish Gambit.

Theory table
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'''1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4'''