Sicilian Defense:Nyezhmetdinov-Rossolimo Attack

Usually called the Rossolimo, after Nicolas Rossolimo. Instead of opening the centre, White pins the c6 knight with 3. Bb5.

It is reached after 5 moves: 1. e4 c5 2. Nf3 Nc6 3. Bb5. It is a line of the Sicilian Defense.

Black is to move and has 25 legal moves. Over the next four moves — two for each side — the game can branch into 693,090 different games. Those games reach 236,445 different positions: most positions can be reached in more than one way, 2.9 on average.

The Lichess opening list names 7 further lines after this position, such as Fianchetto Variation (3... g6) and Brooklyn Retreat Defense (3... Nb8).

The same moves can be played in 3 different legal orders that all reach this position. For example 1. Nf3 c5 2. e4 Nc6 3. Bb5, which starts as the Zukertort Opening.