Nimzo-Indian Defense:Sämisch Variation

Named after Friedrich Sämisch: 4. a3 forces the bishop to decide, accepting doubled pawns for the bishop pair.

It is reached after 7 moves: 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. a3. It is a line of the Nimzo-Indian Defense.

Black is to move and has 33 legal moves. Over the next four moves — two for each side — the game can branch into 926,250 different games. Those games reach 305,949 different positions: most positions can be reached in more than one way, 3 on average.

The Lichess opening list names 3 further lines after this position.

The same moves can be played in 30 different legal orders that all reach this position. For example 1. c4 Nf6 2. d4 e6 3. Nc3 Bb4 4. a3, which starts as the English Opening.