Four Knights Game:Scotch Variation

It is reached after 7 moves: 1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. d4. It is a line of the Four Knights Game.

Black is to move and has 30 legal moves. Over the next four moves — two for each side — the game can branch into 1,280,469 different games. Those games reach 430,692 different positions: most positions can be reached in more than one way, 3 on average.

The Lichess opening list names 8 further lines after this position, such as Scotch Variation Accepted (4... exd4) and Krause Gambit (4... Bb4 5. Nxe5).

The same moves can be played in 144 different legal orders that all reach this position. For example 1. Nf3 e5 2. e4 Nc6 3. Nc3 Nf6 4. d4, which starts as the Zukertort Opening.