Sicilian Defense:Moscow Variation

With 3. Bb5+ White offers to trade bishops and steers the game into calmer waters.

It is reached after 5 moves: 1. e4 c5 2. Nf3 d6 3. Bb5+. It is a line of the Sicilian Defense.

Black is to move and has 4 legal moves. Over the next four moves — two for each side — the game can branch into 100,342 different games. Those games reach 57,294 different positions: most positions can be reached in more than one way, 1.8 on average.

The Lichess opening list names 5 further lines after this position, such as Main Line (3... Bd7) and Dorfman Gambit (3... Nc6 4. O-O Bd7 5. Qe2 g6 6. e5).

The same moves can be played in 4 different legal orders that all reach this position. For example 1. Nf3 c5 2. e4 d6 3. Bb5+, which starts as the Zukertort Opening.