The Sicilian defense is one of the most common used defences, being the main weapon against 1.e2-e4. This is because, by giving up the center and organizing a quick counter-attack on the queen's flank, it takes to a very complicated game, in which players attack on different flanks (white on king's flank, black on queen's flank). In many cases white obtaines space advantage at the beginning (e4 pawn against d6, e6, g6 or combinations). White has the perspective of attacking on the king's flank, moving his "f", "g" and "h" pawns. The possibility that white makes the queenside castle and black kingside leeds to a difficult battle, winner becoming the one that gets there first. This is because black organises a very dangerous counter-attack using the "c" semi-column and advancing his "a" and "b" pawns. He also has a classic manoeuvre to getting his knight from c6 to c4 (Nc6-a5-c4 or Nc6-e5-c4) which usually obliges white to exchange his bishop for that knight, assuring black the pair of white bishops.

    Black can also organise pressure on the e4 pawn (as in the Scheveningen variation) by getting the bishop on b7. Finally, by d6-d5, without allowing white e4-e5, black assures parity.