Slav Defense

The Slav Defense is a chess opening that begins with the moves 1. d4 d5 2. c4 c6. The Slav received an exhaustive test during the two Alekhine–Euwe World Championship matches in 1935 and 1937. Played by 11 of the first 13 world champions, this defense was particularly favored by Euwe, Botvinnik, and Smyslov. Today the theory of the Slav is very extensive and well developed.

Black faces three major problems in many variations of the Queen's Gambit Declined. First, development of the black queen bishop is difficult, as it is often blocked by an e6 pawn. Second, the pawn structure offers White targets, especially the possibility of a minority attack on the queenside in the Exchange variation. Third, White often plays Bg5 to pin the Black knight on f6 against the Black queen, and unpinning it is awkward for Black.

The Slav addresses all of these problems. Black's queen bishop is unblocked, the pawn structure remains balanced, and the move Bg5 is not yet a threat as the unmoved black pawn on e7 prevents the pin. Also, if Black later takes the gambit pawn with ...dxc4, the support provided by the pawn on c6 allows ...b5 which may threaten to keep the pawn, or drive away a white piece that has captured it, gaining Black a tempo for queenside expansion. On the other hand, Black usually will not be able to develop the queen bishop without first giving up the center with ...dxc4, and developing this bishop may leave the Black queenside weak. Additionally, the thematic break ...c5 incurs the loss of a tempo.

The Slav can be entered by many move orders. The possibilities include 1.d4 d5 2.Nf3 Nf6 3.c4 c6, 1.Nf3 d5 2.c4 c6 3.d4 Nf6, and so on. From the standard Slav position (1.d4 d5 2.c4 c6), the following are the most important continuations.

3.Nc3 e5 (Winawer Countergambit)
3.Nc3 e6 (Semi-Slav Defense)
3.cxd5 cxd5 (Slav Exchange Variation)
3.Nf3 e6 (Semi-Slav Defense)
3.Nf3 Nf6 4.Nc3 (main line)
4...a6 (Chebanenko Slav)
4...dxc4 (Slav Accepted)
5.a4 (Alapin Variation)
5...Na6 (Smyslov Variation)
5...e6 (Soultanbéieff Variation)
5...Bf5 (Czech Variation)
6.e3 (Dutch Variation)
6.Ne5 (Krause Attack)
6.Nh4
5...Bg4 (Steiner Variation)
5.e3 (Alekhine Variation)
5.e4 (Slav Gambit)
4...e6 (Semi-Slav Defense)
4...g6 (Schlechter Variation)
3.Nf3 Nf6 4.e3 (Slav Declined)