Queen's Gambit Declined:Cambridge Springs Defense

Named after the 1904 tournament in Cambridge Springs, Pennsylvania. Black’s queen goes to a5 to pin the c3 knight.

It is reached after 12 moves: 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 e6 5. Bg5 Nbd7 6. e3 Qa5. It is a line of the Queen's Gambit Declined.

White is to move and has 34 legal moves. Over the next four moves — two for each side — the game can branch into 1,640,325 different games. Those games reach 565,118 different positions: most positions can be reached in more than one way, 2.9 on average.

The Lichess opening list names 6 further lines after this position, such as Bogoljubow Variation (7. Nd2 Bb4 8. Qc2) and Capablanca Variation (7. Bxf6).

The same moves can be played in 8,640 different legal orders that all reach this position. For example 1. d4 d5 2. c4 Nf6 3. Nf3 c6 4. Nc3 e6 5. Bg5 Nbd7 6. e3 Qa5, which starts as the Queen's Gambit Declined: Marshall Defense.