Bishop's Opening:Berlin Defense

It is reached after 4 moves: 1. e4 e5 2. Bc4 Nf6. It is a line of the Bishop's Opening.

White is to move and has 33 legal moves. Over the next four moves — two for each side — the game can branch into 800,806 different games. Those games reach 269,566 different positions: most positions can be reached in more than one way, 3 on average.

The Lichess opening list names 12 further lines after this position, such as Ponziani Gambit (3. d4) and Vienna Hybrid (3. d3 Nc6 4. Nc3).

The same moves can be played in 2 different legal orders that all reach this position. For example 1. e4 Nf6 2. Bc4 e5, which starts as the Alekhine Defense.