Ruy Lopez:Berlin Defense

An old defence made famous by Vladimir Kramnik, who used it to take the world title from Garry Kasparov in 2000. Its quiet endgame lines earned it the nickname “the Berlin Wall”.

It is reached after 6 moves: 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6. It is a line of the Ruy Lopez.

White is to move and has 32 legal moves. Over the next four moves — two for each side — the game can branch into 842,304 different games. Those games reach 287,278 different positions: most positions can be reached in more than one way, 2.9 on average.

The Lichess opening list names 37 further lines after this position, such as Anti-Berlin Variation (4. d3) and Halloween Attack (4. Nxe5).

The same moves can be played in 18 different legal orders that all reach this position. For example 1. Nf3 e5 2. e4 Nc6 3. Bb5 Nf6, which starts as the Zukertort Opening.