Slav Defense, Czech Variation

The Czech Variation begins when Black’s d5-pawn captures White’s c4-pawn and White answers by advancing the a2-pawn to a4. In algebraic notation, x marks a capture and B means bishop, so dxc4 and Bf5 describe the line’s two central actions. The move a4 restrains b5, Black’s most natural way to support the captured pawn, and makes recovery easier. Black then develops the c8-bishop to f5, outside the pawn chain, before closing that diagonal with e6.

This order expresses a central advantage of the Slav Defense. Black's e-pawn remains on e7 during the opening moves, so the bishop can develop freely. After ...Bf5, Black commonly plays ...e6, ...Bb4, ...Nbd7, and castles. White may choose quiet development with e3 and Bxc4 or challenge the bishop with Ne5 or Nh4.

The fight after c4 is recovered

Recovering the pawn does not end the opening. White wants to play e4 and use the central presence. Black seeks a break with ...c5 or ...e5 rather than merely defending. Because the f5-bishop developed before ...e6, it is often active, but it can also be attacked and forced to lose time.

The difference from a Semi-Slav such as the Stoltz Variation is essential. There Black plays ...e6 early and initially shuts in the c8-bishop. In the Czech Variation, that bishop is already outside when ...e6 appears.