Chigorin, Baltik dan Albin

A Queen's Gambit defense where Black develops the queen-side knight early and pressures the center with pieces instead of reinforcing it with pawns.

A defense in which Black develops the c8-bishop to f5 before supporting the central d5-pawn with the e-pawn.

An aggressive Queen's Gambit reply where Black offers a central pawn and seeks activity through a deeply advanced queen pawn.