Slav Defense: Czech Variation

About this variation

After 4...dxc4 5. a4, Black develops the bishop with 5...Bf5. It is the classical main line of the Slav.

The Czech Variation is the classical main line of the Slav: 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 Bf5. Black takes the c4 pawn, White stops ...b5 with a4, and Black develops the light-squared bishop outside the pawn chain before playing ...e6. That solves the problem that troubles Black in the Queen's Gambit Declined, where the c8 bishop is often shut in.

White's two main tries are 6. e3 followed by Bxc4 and O-O, a calm line where White regains the pawn and aims for a central e4 push, and 6. Ne5 (the Krause Attack), which hits c4 at once: after 6...Nbd7 White recaptures with 7. Nxc4, and after 6...e6 White plays f3 and e4 to gain the center with tempo on the bishop. Both lines have been tested extensively at the highest level, and both give Black a solid, active position when handled well.

Black's typical set-up is ...e6, ...Bb4, ...Nbd7 and ...O-O, with the bishop on b4 pinning the knight and making White's e4 push harder to arrange. Black often plays ...Bg6 or ...Bg4 at the right moment, and the break ...c5 or ...e5 frees the position once development is complete. The b4 square, weakened by White's a4, is a useful outpost for Black's pieces (the bishop on b4, or a knight via a6).

White's plans revolve around the e4 push. If White gets e4 and e5 in with good timing, Black's pieces can be pushed back and White gains space. White also has the bishop pair in some lines after Nh4xf5 or a trade on g6, and can try to use it in an open position.

The Czech Variation suits Black players who want a solid but active defense against 1. d4 with clear plans. Learning the key ideas, such as the bishop on f5 and the pin with ...Bb4, is more useful than memorizing long lines, since the same patterns appear across all of White's tries.

It is one of the main lines of the Slav Defense.