Halloween Gambit

The Halloween Gambit (also known as the Müller–Schulze Gambit or Leipzig Gambit) is an aggressive chess opening which begins with these moves:
 e4 e5
 Nf3 Nc6 
 Nc3 Nf6 (Four Knights Game)
 Nxe5?!
White sacrifices a knight early to get fast development and attack Black’s position. If Black does not prepare, White can get an initiative.https://www.chess.com/openings/Four-Knights-Game-Halloween-Gambit

 History 
The Halloween Gambit appeared in the late 19th century, about 1888. At that time, it was called the Müller–Schulze Gambit (a type of joke by German players,  similar to Jones and Smith in English) or the Leipzig Gambit. But Rainer Schlenker, who loved strange openings, renamed it the Halloween Gambit in his Randspringer magazine in December 1993. This name is actually based on how players, when they first see the unexpected and weird fourth move of White, are extremely shocked, as if they were scared when faced with a "Halloween mask".https://zimbeckchess.com/UON13HalloweenGambit.pdf

 Main line 
The main line continues 4... Nxe5 (White tries to push Black’s knights back) 5. d4 Ng6 6. e5 Ng8 and 7. Bc4. This move puts pressure on f7 and tries to keep Black’s pieces passive. After this move, Black has lots of ways to play:
7...d6?!
After 7...d6, White threatens checkmate with 8.Qf3. Then if Black plays 8...Qe7, White will continue with 9. O-O dxe5 and 10. Nd5 (Black just develops a queen and a knight, White has more central squares and threatens to take Black's queen). If Black plays 8...Qd7, it will block the bishop’s development and create a defensive position for Black. The best move for Black is 8...Be6 - a natural move is just able to play if Black knows the theory.

References

Category:Chess openings