The Slav defence is an important reply to 1d4. It is popular with top players. The Slav usually begins:
1.d4 d5
2.c4 c6 (this is the characteristic move of the Slav) 3.Nf3 Nf6 4.Nc3 (see diagram) Other fourth moves for White are 4.e3, 4.cxd5 and 4.Qb3.
The Slav proper
Now 4...dxc4 is the Slav:
Mainline
This line was explored in two world championship matches between Alekhine and Euwe in 1935 and 1937.
5.a4 Bf5
6.e3 e6
7.Bxc4 Bb4
8.0-0 0-0
Slav Gambit
5.e3 or e4
with 5...b5 Black keeps the pawn
The Semi-Slav
4...e6 is the Semi-Slav:
The Russian variation
Sometimes called the Botvinnik variation.
5.Bg5 dxc4
6.e4 b5
7.e5 h6
8.Bh4 g5
9.Nxg5 hxg5
10.Bxg5 Nbd7
11.exf6 Bb7
12.g3 Bb7
The Meran defence
5.e3 Nbd7
6.Bd3 dxc4
7.Bxc4 b5
8.Bd3 Bb7
9.0-0 a6
10.e4 c5
References
Matthew Sadler 1997. The Slav. Chess Press, Brighton
Matthew Sadler 1998. The Semi-Slav. Chess Press, Brighton.