Catalan Opening:Closed

It is reached after 9 moves: 1. d4 Nf6 2. c4 e6 3. g3 d5 4. Bg2 Be7 5. Nf3. It is a line of the Catalan Opening.

Black is to move and has 33 legal moves. Over the next four moves — two for each side — the game can branch into 1,353,504 different games. Those games reach 436,738 different positions: most positions can be reached in more than one way, 3.1 on average.

The Lichess opening list names 16 further lines after this position, such as Open Defense, Classical Line (5... O-O 6. O-O dxc4).

The same moves can be played in 720 different legal orders that all reach this position. For example 1. c4 Nf6 2. d4 e6 3. g3 d5 4. Bg2 Be7 5. Nf3, which starts as the English Opening.