Sicilian Defense:Classical Variation

It is reached after 10 moves: 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6. It is a line of the Sicilian Defense.

White is to move and has 43 legal moves. Over the next four moves — two for each side — the game can branch into 2,052,753 different games. Those games reach 661,632 different positions: most positions can be reached in more than one way, 3.1 on average.

The Lichess opening list names 36 further lines after this position, such as Richter-Rauzer Variation (6. Bg5) and Sozin Attack (6. Bc4).

The same moves can be played in 732 different legal orders that all reach this position. For example 1. Nf3 c5 2. e4 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6, which starts as the Zukertort Opening.