The Keres Attack in the Sicilian Defense, 1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 d6 6.g4!?, is an aggresive opening for White. There were a few correspondence games with this opening in 1900, but it was Paul Keres who first employed it at a major tournament. In 1943, he defeated former world champion challenger Efim Bogoljubow in round 1 at Salzburg, Austria with this opening. Bogoljubow had to resign as he was about to lose his queen or get checkmated. Since this game, the opening has been played hundreds of times by the top players in the world. They are still discovering new moves for both White and Black in this interesting opening.