Chess Openings Lab
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Slav Defense: Czech Variation

The Czech Variation is 4...dxc4 5.a4 Bf5, where Black develops the c8 bishop before playing ...e6. White wants to regain c4 with Ne5 or Bxc4 and then push e4, while Black aims for ...e6, ...Bb4 and the ...e5 or ...c5 breaks.

Moves
1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5
ECO
D17
Engine
+0.40 · a slight edge for White (Stockfish 17.1, depth 20)
Played
477 games in our lichess sample
White scores
51.4%

Key ideas for both sides

White

  • 6.Ne5 hits c4 and prepares f3 and e4, as in the top engine line.
  • 6.e3 with Bxc4 and short castling gives a calm, solid game with Qe2 and e4 later.
  • 6.Nh4 targets the f5 bishop to win the bishop pair before Black can retreat it.
  • After Nxc4, use g3 and Bg2 to support the e4 push and watch the long diagonal.

Black

  • Against 6.Ne5, play ...Nbd7 to challenge the knight, then ...Qc7 and ...e5.
  • After 6.e3, develop with ...e6 and ...Bb4, pinning the c3 knight to slow down e4.
  • ...e5 is the key break to free the position once the queen supports it.
  • The a4 push left a hole on b4, a natural home for the f8 bishop or a knight.

Plans and pawn structure

The Czech is a solid main line. White wins back c4 and tries for e4; Black develops with ...e6, ...Bb4, ...Nbd7 and castles. The bishop on b4 pins the c3 knight, making e4 harder to achieve. Black's freeing breaks are ...c5 and ...e5. White's a4 pawn stops ...b5 for good but gives Black the b4 square, so the fight is often about whether White can push e4 before Black hits back in the center.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.40: a slight edge for White. Its three top choices for White:

  1. +0.40 6.Ne5 Nbd7 7.Nxc4 Qc7 8.g3 e5
  2. +0.24 6.e3 e6 7.Bxc4 Bb4 8.O-O O-O
  3. +0.10 6.Nh4 Bd7 7.e3 b5 8.Nf3 a6

Pawns, from White's side.

How it scores on lichess

477 rated lichess games reached this position; White scored 51.4%.

1600–199953.7%
2000 and up50.3%

Light: White wins. Grey: draws. Dark: Black wins. About the sample.

Where it goes next

  • Czech Variation, Bled Attack6.Nh4 · rare
  • Czech Variation, Carlsbad Variation, Morozevich Variation6.Ne5 · rare
  • Czech Variation, Dutch Variation, Sämisch Variation6.e3 · rare

How to play against it

As White, regain c4 with Ne5 or Bxc4 and work toward e4 with Qe2 and Rd1. Do not let the bishop on b4 sit on your knight without a plan to unpin it. Avoid trading on f5 too early if it hands Black easy development.

Questions

What are the moves of the Slav Defense: Czech Variation?

The Slav Defense: Czech Variation starts 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5. Its ECO code is D17.

Is the Slav Defense: Czech Variation good for Black?

Stockfish 17.1 rates the position +0.40 at depth 20, which is a slight edge for White. In 477 lichess games from our sample, White scored 51.4%. A reliable main line for Black players who like solid development; White needs precision to keep any edge.

What is the main idea of the Slav Defense: Czech Variation?

Black develops the bishop to f5 before ...e6, and White regains c4 aiming for e4. The fight centers on whether White can push e4 or Black can break first with ...e5 or ...c5.

What should White play next?

The engine's first choice is Ne5, with e3 and Nh4 close behind. 6.Ne5 hits c4 and prepares f3 and e4 to take the center.

Updated October 2026. Sources and method.