Gain central space after the pawn offer: Rousseau Gambit line

Offer your f-pawn. If White accepts, advance your e-pawn against the knight and support it with your d-pawn.

1. e4
2. e5
3. Nf3
4. Nc6
5. Bc4
6. f5
7. exf5
8. e4
9. Ng1
10. d5