Slav Defense:Exchange Variation

It is reached after 5 moves: 1. d4 d5 2. c4 c6 3. cxd5. It is a line of the Slav Defense.

Black is to move and has 30 legal moves. Over the next four moves — two for each side — the game can branch into 831,102 different games. Those games reach 274,744 different positions: most positions can be reached in more than one way, 3 on average.

The Lichess opening list names 3 further lines after this position, such as Symmetrical Line (3... cxd5 4. Nc3 Nf6 5. Nf3 Nc6 6. Bf4 Bf5) and Boor Attack (3... cxd5 4. Nc3 Nf6 5. f3).

The same moves can be played in 5 different legal orders that all reach this position. For example 1. c4 d5 2. d4 c6 3. cxd5, which starts as the English Opening.