Danish Gambit Accepted

It is reached after 6 moves: 1. e4 e5 2. d4 exd4 3. c3 dxc3.

White is to move and has 42 legal moves. Over the next four moves — two for each side — the game can branch into 1,580,899 different games. Those games reach 497,733 different positions: most positions can be reached in more than one way, 3.2 on average.

The Lichess opening list names 4 further lines after this position, such as Chigorin Defense (4. Bc4 cxb2 5. Bxb2 Qe7) and Classical Defense (4. Bc4 cxb2 5. Bxb2 Nf6).

The same moves can be played in 4 different legal orders that all reach this position. For example 1. d4 e5 2. e4 exd4 3. c3 dxc3, which starts as the Queen's Pawn Game.