Sicilian Defense:Hyperaccelerated Dragon

It is reached after 4 moves: 1. e4 c5 2. Nf3 g6. It is a line of the Sicilian Defense.

White is to move and has 28 legal moves. Over the next four moves — two for each side — the game can branch into 477,153 different games. Those games reach 167,028 different positions: most positions can be reached in more than one way, 2.9 on average.

The Lichess opening list names 17 further lines after this position, such as Acton Extension (3. c4 Bh6) and Pterodactyl Defense, Western, Pterodactyl (3. c3 Bg7 4. d4 Qa5).

The same moves can be played in 4 different legal orders that all reach this position. For example 1. Nf3 c5 2. e4 g6, which starts as the Zukertort Opening.