Alekhine Defense:Exchange Variation

It is reached after 9 moves: 1. e4 Nf6 2. e5 Nd5 3. d4 d6 4. c4 Nb6 5. exd6. It is a line of the Alekhine Defense.

Black is to move and has 30 legal moves. Over the next four moves — two for each side — the game can branch into 1,282,013 different games. Those games reach 424,886 different positions: most positions can be reached in more than one way, 3 on average.

The Lichess opening list names 2 further lines after this position, such as Voronezh Variation (5... cxd6 6. Nc3 g6 7. Be3 Bg7 8. Rc1 O-O 9. b3) and Karpov Variation (5... cxd6 6. Nc3 g6 7. h3 Bg7 8. Nf3 O-O 9. Be2 Nc6 10. O-O Bf5 11. Bf4).

The same moves can be played in 70 different legal orders that all reach this position. For example 1. d4 Nf6 2. e4 Nd5 3. e5 d6 4. c4 Nb6 5. exd6, which starts as the Queen's Pawn Game.