Poison Pawn Sicilian
The Poison Pawn variations in the Sicilian Nadjorf Defence is a strong and popular opening for Black. It looks horrible, with Black flouting basic opening principles by chasing a free "b’ pawn (the “poison pawn”). White gets an attacking position, lots of space, lots of piece play, and yet surprisingly, Black has no real weaknesses and defences have been found. Many grandmasters play this line for Black as part of their main opening repertoire.
Diagram: Poison Pawn Variation in Sicilian Nadjorf Defence
Other main line “open” Sicilian Defence variations include: