Halloween Attack

The Halloween Attack is a speculative piece sacrifice against the Berlin Defense: 4. Nxe5 gives up the knight for the e5-pawn, hoping to chase Black's pieces with central pawns. It resembles the Halloween Gambit of the Four Knights Game, but with the bishop on b5 rather than a knight on c3, White gains less space. Black usually accepts with 4...Nxe5, engines give Black a large advantage, and Black scores heavily in practice.