The Slav defence is an important reply to 1d4. It is popular with top players. The Slav usually begins:
| a | b | c | d | e | f | g | h | ||
| 8 | 8 | ||||||||
| 7 | 7 | ||||||||
| 6 | 6 | ||||||||
| 5 | 5 | ||||||||
| 4 | 4 | ||||||||
| 3 | 3 | ||||||||
| 2 | 2 | ||||||||
| 1 | 1 | ||||||||
| a | b | c | d | e | f | g | h | ||
Other fourth moves for White are 4.e3, 4.cxd5 and 4.Qb3.
Now 4...dxc4 is the Slav:
This line was explored in two world championship matches between Alekhine and Euwe in 1935 and 1937.
Sometimes called the Botvinnik variation.