Key ideas
- 4...Nf6 transposes to the Two Knights Defense. 5.e5 is met by 5...d5 6.Bb5 Ne4 7.Nxd4, while 5.O-O allows the Max Lange Attack after 5...Bc5 6.e5, or 5...Nxe4 6.Re1 d5 7.Bxd5 Qxd5 8.Nc3.
- 4...Bc5 5.c3 Nf6 6.cxd4 Bb4+ reaches a classical Giuoco Piano position by transposition, with White's big pawn centre against Black's quick development. 5.Ng5, attacking f7 at once, is a riskier option.
- 4...Bb4+, the London Defense, gains time with the check. After 5.c3 dxc3 6.bxc3 the bishop retreats and Black keeps an extra pawn but falls behind in development.
- The key motifs are Ng5 and Bxf7+ against f7, and Re1 with the e5 push against a black king still in the centre.
Plans for White
Play for development and open lines rather than the d4 pawn: O-O, e5, Re1 and c3 open the position, and Ng5 or Bxf7+ appear when Black's king is still on e8. Regaining d4 with Nxd4 is fine when it comes with tempo.
Plans for Black
Return the pawn when needed to finish development. 4...Nf6 with ...d5 or ...Nxe4 is the most direct, and 4...Bc5 leads to well-mapped classical positions. Avoid lines that leave f7 and the e-file exposed for long.
For the wider picture, see the Scotch Game guide.