Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...f5/4. d4
This variation counterattacks in the center by challenging the e-pawn, like the Vienna Gambit with 1. e4 e5 2. Nc3 Nf6 3. f4 d5. Black's best and by far most common option is 4...fxe4.
4. ...fxe4
[edit | edit source]If Black takes the e-pawn, White's has two main options. 5. Nxe5 wins the pawn back, but runs into complications after 5. ... Nxe5 6. dxe5 c6. Now if the white bishop retreats, Black has 7... Qa5+ winning the e5 pawn and leaving Black better. (Note that in the Deferred Schliemann, because the white bishop is no longer on b5, c6 no longer comes with tempo, so this line is worse for Black. Thus, 5. d4 is the most common response to the Delayed Schliemann.) Thus, the most common line for white is 7. Nc3?!, a piece sacrifice. Play usually follows 7... cxb5 8. Nxe4 d5 9. exd6 Nf6, with an unclear position.
The other option is 5. Bxc6, after which Black enjoys the two bishops in exchange for a worse pawn structure and a white knight on e5 after either recapture on c6. 5... exf3 is less recommended, as after 6. Bxf3 White can quickly castle and place pressure along the e file.
4. ... exd4
[edit | edit source]If Black takes the d-pawn, White's most common move according to Lichess's Master games explorer is e5, pushing the pawn forward and taking control of the f6 and d6 squares.
4. ... Nxd4
[edit | edit source]If Black takes the d-pawn with the knight (which resembles the Ruy Lopez Bird Variation), it hits the bishop on b5, so Nxe5 is not an option. 5. Nxd4 is the most common move, followed by 5. ... exd4 6. O-O c6.
4. ... Nf6
[edit | edit source]If Black plays Nf6, 5. dxe5 is the most common move, followed by 5. ... Nxe4.