Slav Defense

The idea: hold d5 without locking in the bishop

Against 2.c4, Black wants to keep a pawn on d5. Supporting it with 2...e6 is the Queen's Gambit Declined: solid, but the c8-bishop stays shut in. 2...c6 supports d5 with the other pawn and leaves the c8-h3 diagonal open: the bishop can come out to f5 or g4 before ...e6 completes the structure.

It is the same idea as the Caro-Kann Defense against 1.e4: first ...c6, then the bishop out, then ...e6. The final setup, with pawns on c6, d5 and e6 and the bishop in front of the chain, is very hard to attack.

The c6-pawn has a second job: it prepares ...dxc4 followed by ...b5, which would hold on to the captured pawn. White must always keep an eye on c4, and this threat explains several of White's moves in the main line.

The price: the b7-pawn and the b8-knight

Once the bishop has left c8, the b7-pawn is no longer protected. White's standard answer is Qb3, which attacks it, often together with another weak point. In the position shown, Black defends b7 with ...Qc7 or ...Qc8; when Black is unprepared, the same Qb3 wins a pawn (see the trap below).

The c6-pawn also takes the b8-knight's best square. The knight therefore often develops to d7, and sometimes to a6 on its way to b4, as in the Smyslov Variation (4.Nc3 dxc4 5.a4 Na6).

Three choices for White

The main move is 3.Nf3, and after 3...Nf6 White picks the type of game on move four. White can also play 3.Nc3, or exchange at once with 3.cxd5, with similar ideas.

4.Nc3 dxc4 5.a4 Bf5, the main line

With 4.Nc3, White allows the capture on c4. After 4...dxc4, 5.a4 stops ...b5, which would hold the pawn: this is the Alapin Variation. 5...Bf5, the Czech Variation, develops the bishop and prevents e4. White wins c4 back later, with e3 and Bxc4 or with Ne5 and Nxc4.

4.e3, the Quiet Variation

White protects c4 in advance, at the cost of a c1-bishop shut in behind e3. Black has no pawn to win and often develops the bishop at once, to f5 or g4, before playing ...e6.

4.cxd5, the Exchange Variation

After 4...cxd5, the structure is symmetrical and the c-file opens. White keeps only the advantage of the move; Black equalizes without much trouble by staying alert to b7 once the bishop is out. The exchange can also come at once with 3.cxd5 cxd5.

The Semi-Slav, a different approach

After 3.Nf3 Nf6 4.Nc3, Black can play 4...e6 instead of 4...dxc4. This is the Semi-Slav Defense: the e6-pawn closes the c8-bishop's diagonal, as in the Declined, but the c6-d5-e6 chain makes Black's center very solid.

In return for the locked-in bishop, Black keeps the threat of ...dxc4 followed by ...b5, which gains space on the queenside and prepares ...Bb7. The Semi-Slav leads to sharper positions than the Slav and requires a lot of theory: it is an opening in its own right.

Another option on move four, 4...a6, the Chebanenko Variation, prepares ...b5 without closing the bishop's diagonal.

The main-line structure

In the main line, after 6.e3 e6 7.Bxc4 Bb4 8.O-O O-O, White has won the pawn back. White has an extra central pawn on d4, but Black's c6- and e6-pawns have no weaknesses, and the f5-bishop is active in front of them.

The whole fight revolves around the e4-square. White wants to push the e-pawn there to drive away the f6-knight and take the center; Black controls it with the f5-bishop, the f6-knight and the ...Bb4 pin on the c3-knight.

If White achieves e4 under good conditions, White gains space. If not, Black strikes in turn with ...c5 or ...e5, and the black pieces get room to breathe.

Plans for both sides

In the same main-line position, each side has two main ideas.

White

• Prepare e4 Qe2, often Rd1 next, and then e4: White supports the push before playing it, to drive away the f6-knight and take the center.
• Take the f5-bishop Nh4 attacks the f5-bishop: by trading it, White gets the bishop pair and removes a piece that watches e4.

Black

• Hold the e4-square The f5-bishop, the f6-knight and the ...Bb4 pin control e4. As long as White cannot advance there, the extra central pawn achieves nothing.
• The ...c5 and ...e5 breaks Once ...Nbd7 is in, Black hits d4 with ...e5 or ...c5 to give the pieces room.

Common mistakes by Black

They come up often among players who are new to the Slav.

• Forgetting b7 once the bishop is out: Qb3 is White's standard reply, and you need to know how to defend that pawn before playing ...Bf5.
• Clinging to the c4-pawn after 5.a4: ...b5 is no longer possible and the pawn goes back to White. Use the b4-square instead, weakened by a4, for the bishop or the knight.
• Playing ...e6 before developing the bishop: the c8-bishop ends up shut in, and you drift into a Semi-Slav or a Declined without meaning to, with different plans.
• In the Exchange Variation, copying all of White's moves: with an extra tempo, White gets to the c-file or to b7 first.

Frequently asked questions

Is the Slav Defense good for beginners?

Yes. The plans are clear: hold d5, develop the c8-bishop before ...e6, then free the position with ...c5 or ...e5. You only need to watch the b7-pawn and know the idea of 5.a4 in the main line.

What is the difference between the Slav and the Semi-Slav?

In the Slav, Black develops the c8-bishop before playing ...e6. In the Semi-Slav (3.Nf3 Nf6 4.Nc3 e6), Black plays ...e6 first: the bishop is shut in, but the center is more solid and the positions are sharper.

Slav or Queen's Gambit Declined?

Both hold d5. The Declined (2...e6) keeps a very stable center but shuts in the c8-bishop; the Slav frees that bishop at the cost of a more sensitive b7-pawn and a less well-placed b8-knight. Choose based on the positions you enjoy playing.

Is the Slav the Caro-Kann against 1.d4?

The idea is the same: ...c6 to support d5, then the c8-bishop out before ...e6. The structures look alike, and a Caro-Kann player quickly feels at home in the Slav.

How do you play against the Exchange Slav?

Keep it simple: develop your pieces (...Nc6, ...Bf5, ...e6), watch b7 and the c-file, and don't copy White blindly. The position is symmetrical and calm, and Black equalizes without much risk.