Chess opening
The Rousseau Gambit (or Ponziani Countergambit after Domenico Lorenzo Ponziani) is a chess opening that begins with the moves:
1. 
2. 
3. 
The gambit is named after French chess master Eugène Rousseau. White can decline the gambit by supporting the e-pawn with 4.. The resulting position is similar to a King's Gambit Declined with colours reversed, and White's ;dfn id="" ;king bishop ;/dfn ; aiming at Black's weakened ;dfn id="" ;kingside ;/dfn ;. Black will have trouble castling kingside, and Ng5 is a likely threat. White's position is better, but still requires careful play.
Key themes for White are to attack Black's kingside and to avoid attempts by Black to ;dfn id="" ;simplify ;/dfn ; the position. Exchanges involving White's ;dfn id="" ;light-square bishop ;/dfn ; are particularly suspect.
 ;templatestyles src="Template:TOC_left/styles.css" / ;
White responses.
Gambit Declined: 4.d3.
White can decline the gambit and wait to capture the f-pawn. 4...Bc5 transposes to the Lucchini Gambit.
Gambit Accepted: 4.exf5.
White still has a good game after the inferior 4.exf5, but the position is less clear. Black usually plays 4...e4, which White may meet by 5.Nd4! Nf6 (5...Nxd4? leads to trouble after 6.Qh5+) 6.Nxc6.
4.d4!
White gets a clear advantage with 4.d4!:
References.
 ;templatestyles src="Reflist/styles.css" / ;