Openings · D10–D19

Slav Defence

Defend the gambit pawn with the c-pawn instead of the e-pawn, and keep the light-squared bishop free.

1.d4 d5 2.c4 c6played as Black

Play it through on the board below.

Practise the line

You play Black; the other side answers on its own. Nothing here is saved or graded.

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7
h8
g
f
e
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c
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a
Your move 1 of 20/2
  1. 1.d4d5
  2. 2.c4c6

White is answering…

The idea

…c6 does the same job as the Queen's Gambit Declined's …e6 and leaves the c8 bishop a way out. That single difference — the bishop reaching f5 or g4 before …e6 is played — is the whole reason the Slav exists and has been a world-championship opening for a century.

The main line runs 4.Nf3 dxc4 5.a4 Bf5, where Black takes the pawn, gets the bishop out and gives the pawn back later. The order matters more than in almost any other opening: bishop first, then …e6.

Common mistakes

Three that come up again and again below master level: named traps and the errors every coach corrects.

Trying to keep the pawn with ...b5

After 7.Nxb5
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
The mistake
Holding on to the c4 pawn with …b5 after a4.
Why it costs
The a-file opens behind the pawn on b5, and it cannot be held: both 7.Nxb5 and the quieter 7.b3 win the material back, and Black is left with a broken queenside and a bishop on c8 that still has not moved. The pawn on c4 was never keepable — a4 is the move that proves it.
Instead
5…Bf5, the main line. The pawn goes back and Black gets the bishop outside the pawn chain, which is worth more than the pawn ever was.

The bishop out one move early

After 6.Qb3
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
The mistake
Playing …Bf5 while the queen's diagonal to b7 is still open.
Why it costs
6.Qb3 hits b7 and d5 at once. The b7 pawn is defended only by the bishop that has just left, and Black is already making concessions — …Qc8 or …Qb6 — on move six.
Instead
Take on c4 first: the whole point of 4…dxc4 5.a4 Bf5 is that the b7 pawn is not hanging in that order.

Copying to the end in the Exchange

After 8.Bb5
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
  8. 8.
The mistake
Mirroring White's moves in the Exchange Slav.
Why it costs
Symmetry favours the player to move: 8.Bb5 pins first, and every subsequent trade happens on White's terms. The position is drawish, but a drawish position played a tempo down is still a position where only one side can go wrong.
Instead
Break the symmetry early with …a6 and …e6, or …Qb6 hitting b2. A drawn ending has to be aimed at, not copied into.

What the engine says

After 1.d4 d5 2.c4 c6, these are White's six best moves according to Stockfish, with the bar showing White's chance of winning. The whole list sits within 3 percentage points of win chance: none of them is a mistake, and the choice is about the positions you want to play.

  1. Nf3+0.3
  2. Nc3+0.3
  3. cxd5+0.3
  4. e3+0.2
  5. Bd2+0.1
  6. Qb3+0.0

The engine's main line from Nf3: Nf3 Nf6 Nc3 dxc4 a4 Bf5 e3 e6.

Stockfish 18, depth 24. Scores are in pawns from White's side. Another engine or depth will move individual numbers a little; the picture does not change. How we check.

Where it fits

The Slav Defence is a variation of the Queen's Gambit, whose page covers the ideas this one takes for granted.

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