Queen's Gambit Declined

Black supports d5 with 2...e6 — one of the most solid defences in chess and a regular guest in world championship matches.

It is reached after 4 moves: 1. d4 d5 2. c4 e6.

White is to move and has 30 legal moves. Over the next four moves — two for each side — the game can branch into 992,712 different games. Those games reach 322,443 different positions: most positions can be reached in more than one way, 3.1 on average.

The Lichess opening list names 147 further lines after this position, such as Queen's Knight Variation (3. Nc3) and Tarrasch Defense, Pseudo-Tarrasch (3. Nf3 c5).

The same moves can be played in 4 different legal orders that all reach this position. For example 1. c4 d5 2. d4 e6, which starts as the English Opening.