Cambridge Springs Defense

The defining move 6...Qa5 lifts the pin on the f6-knight and pins White's c3-knight against the king in its place. Black plans ...Bb4 and often ...Ne4 to load the a5–e1 diagonal, and a well-timed ...dxc4 can uncover tactics against the bishop on g5, which the queen then hits. Emanuel Lasker used it as early as 1892. The name comes from a 1904 tournament at Cambridge Springs, Pennsylvania, where it appeared several times. Alekhine beat Capablanca with it in their 1927 title match, and Carlsen won with it against Gelfand at the 2013 Candidates.

7. Nd2 is the principled reply, breaking the diagonal and eyeing c4. After 7...Bb4 8. Qc2, the Bogoljubow Variation, 8...O-O 9. Bh4 is the Argentine Variation, while 9. Bd3 drops a piece to 9...dxc4. 7...dxc4 is the Rubinstein Variation. The Capablanca Variation, 7. Bxf6, gives up the bishop to sidestep the tactics altogether and is the most frequent choice online. 7. cxd5 Nxd5, the Yugoslav Variation, usually continues 8. Qd2 Bb4 9. Rc1. The engine considers the position roughly balanced, and Black scores slightly better than White in online games.