1.e4 e5 2.d4 exd4 3.Nf3 Nc6 4.c3 (or 2.Nf3 Nc6 3.d4 exd4 4.c3)
Göring Gambit coverage
Coverage of Black’s alternatives to 4...d5 and 4...dxc3. These options generally fall short of full equality, but 4...Nge7 and 4...Nf6 are reasonable tries for Black and are worth knowing about, and are also relevant for the theory of the Ponziani Opening (1.e4 e5 2.Nf3 Nc6 3.c3 Nge7 4.d4 exd4, and 3...Nf6 4.d4 exd4, are the respective transpositions).
A close look at Black’s most tried and trusted way of declining the gambit: 4...d5. White cannot get a theoretical advantage against it, but has ways to keep the play unbalanced and sharp. Most variations lead to positions where White has an isolated pawn on d4 and temporarily falls behind in development, but is then able to generate active piece play into the middlegame.
Recapturing the pawn and developing a piece at the same time makes sense. White will generally follow up with Bc4, with ideas of Qb3 and/or Ng5 putting pressure on f7, and other motifs include Nc3-d5 and hitting a premature ...Nf6 with e4-e5. The main objection has traditionally been the line 5...Bb4 6.Bc4 d6, but I think White is doing fine there after 7.Ng5.
White sacrifices a second pawn in order to accelerate development. 5...cxb2 is the most theoretically critical response but it is also very dangerous, so Black often prefers to decline the pawn on b2. In most cases White’s best is then to play 6.Nxc3 transposing to 5.Nxc3 lines, but there are some independent alternatives; in particular after 5...Bb4, both 6.0-0 and 6.bxc3 are promising for White.
This line is very hard to assess, as Black gets two extra pawns but White gets a very strong initiative. The standard motifs are generally the same as in the 5.Nxc3 lines, but White has additional pressure on the a1-h8 diagonal. 6...Bb4+ and 6...d6 are the only lines that seriously test the soundness of the 5.Bc4 variation.