The Modern Benoni is a fighting and doubleedged opening, in which Black deliberately takes risks in order to achieve active play. The move order 2...c5 3.d5 e6 4.Nc3 exd5 5.cxd5, which characterises the Modern Benoni, creates for White a dangerous pawn majority in the centre; his simple and effective plan is, after due preparation by f4, the pawn thrust e4-e5. It is however not easy to seize the best moment for this pawn advance. There are systems in which White gets in the move e5 at a very early stage, and there are others in which he holds back his main trump for a long time. But Black has of course got something in return: the pawn majority on the queenside which he can mobilise by means of ...a6 and ...b5, the semiopen e-file where he can exert pressure against the e4-pawn, the Bg7 which can become very strong on the h8-a1 diagonal and the outpost on e5 which is an ideal square for the knight.
In the Benko Gambit, named after the Hungarian-American grandmaster Pal Benko, Black offers his b-pawn as early as on move three. If White accepts the sacrifice with 4.cxb5 a6 5.bxa6 g6 6.Nc3 Bxa6 then Black will for a long time exert unpleasant pressure on the queenside via the semi-open a- and b-files.