Open Defense, Classical Line

The Classical Line (ECO E05) is the branch of the Open Catalan in which Black, after 4...dxc4 5. Nf3, continues kingside development with 5...Be7 instead of spending tempi to defend the extra pawn. The same position can also arise from a Closed Catalan move order. Black normally plans to give the c4-pawn back in exchange for time. With the d5-pawn gone, however, the g2 bishop works along the open long diagonal and makes Black's queenside development awkward. Holding on to the pawn requires ...a6 and ...b5, which loosen Black's queenside considerably.

White most often castles with 6. O-O, by far the most popular choice, and later regains the pawn with Qc2 followed by a4, Ne5 or Qa4+. The immediate 6. Qa4+ and 6. Ne5 recover the material more directly. The engine rates the position as roughly balanced, though White scores well in practice. Among strong players, Anatoly Karpov and Efim Geller favored the Open Catalan with Black, and Oleg Romanishin took it on as White.