Semi-Slav Defense

Semi-Slav Defense
abcdefgh
8
a8 black rook
b8 black knight
c8 black bishop
d8 black queen
e8 black king
f8 black bishop
h8 black rook
a7 black pawn
b7 black pawn
f7 black pawn
g7 black pawn
h7 black pawn
c6 black pawn
e6 black pawn
f6 black knight
d5 black pawn
c4 white pawn
d4 white pawn
c3 white knight
f3 white knight
a2 white pawn
b2 white pawn
e2 white pawn
f2 white pawn
g2 white pawn
h2 white pawn
a1 white rook
c1 white bishop
d1 white queen
e1 white king
f1 white bishop
h1 white rook
8
77
66
55
44
33
22
11
abcdefgh
Moves1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 e6
ECOD43–D49
ParentQueen's Gambit

The Semi-Slav Defense is a variation of the Queen's Gambit Declined chess opening defined by the position reached after the moves:

1. d4 d5
2. c4 c6
3. Nf3 Nf6
4. Nc3 e6

The position may readily be reached by a number of different move orders. Black's supporting pawns resemble a mixture of the Orthodox Queen's Gambit Declined, e6, and the Slav Defense, c6.

Black is threatening to capture the white pawn on c4 and hold it with ...b7–b5. White can avoid this in a number of ways. About 80% of games continue 5.Bg5 or 5.e3: the former constitutes a sharp pawn sacrifice, while the latter restricts the dark-squared bishop from its natural development to g5. Other possible moves are 5.Qb3, 5.g3 and 5.cxd5, the last of which, after 5...exd5, leads to a line of the QGD Exchange Variation where White's early Nf3 enables Black's queen bishop to freely develop, which should give equality (ECO codes D43 and D45). 5.Bf4 is considered somewhat inaccurate, as 5...dxc4 is favorable for Black.

The Semi-Slav is designated by codes D43 through D49 in Encyclopaedia of Chess Openings.