The Janowski Variation of the Queen's Gambit Declined arises after 1.d4 d5 2.c4 e6 3.Nc3 a6. Black plays …a6 to prepare the queenside expansion …b5 , aiming to challenge White's c4 pawn and gain space. The idea was introduced by the Polish French grandmaster Dawid Janowski around the turn of the 20th century.
Compared with classical QGD lines, this variation is less theoretical and offers flexible development for Black. White usually responds by strengthening the center and preventing …b5, often with moves like a4, Nf3, or cxd5. The resulting positions typically feature a strategic battle between White's central control and Black's queenside expansion.