The Haxo Gambit is a chess opening that arises from the Italian Game. The moves are as follows:

1. e4 e5
2. Nf3 Nc6
3. d4 exd4
4. Bc4 Bc5
5. c3

This opening is considered a gambit because White sacrifices a pawn (d4) in exchange for rapid development and pressure on Black's position.

After 5...dxc3, White has the option of playing 6. Bxf7+ Kxf7 7. Qd5+, forcing the king to move and winning the bishop on c5. However, this line is not considered the best continuation for White, as Black can defend the bishop with 7...Kf8 and maintain a lead in material.

Instead, after 5...dxc3, White often plays 6. O-O, castling kingside and bringing the rook into play. Black can then respond with 6...Nge7, defending the knight on c6 and preparing to castle kingside.

Alternatively, Black can decline the gambit by playing 4...d6 or 4...Nf6 instead of 4...Bc5. This leads to more solid and positional play, but it also allows White to develop more freely.

Overall, the Haxo Gambit is a sharp and aggressive opening that can catch unprepared opponents off guard. However, it also requires careful play and accurate calculation to maintain the initiative and avoid falling behind in material.