Cambridge Springs Defense

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In chess, the Cambridge Springs Defense (or less commonly, the Pillsbury Variation) is a variation of the Queen's Gambit Declined beginning with the moves

:1.d4 d5:2.c4 e6:3.Nc3 Nf6:4.Bg5 Nbd7:5.Nf3 c6:6.e3 Qa5

The Encyclopaedia of Chess Openings code is D51.

Black breaks the pin on the h4-d8 diagonal and forms a pin of his own on the c3 knight (exploiting the absence of the queen's bishop from the queenside). If Black later plays dxc4, there may be threats against the g5 bishop. Note that 5. cxd5 cannot win a pawn because of the Elephant Trap. The main line continues 7 ... Bb4 with the threat of Ne4 and pressure along the a5-e1 diagonal. White has several choices at his seventh move. The most common are:

*7. Nd2 (the main line) immediately breaks the pin on the c3 knight and defends e4; 7 ... Bb4 is answered by Qc2, defending the c3 knight and covering e4.
*7. cxd5 avoids complications by clarifying the situation in the center. Black's strongest is the recapture Nxd5, continuing the attack on c3.
*7. Bxf6 avoids tactics involving discovered attacks on the g5 bishop.

The first recorded instance of this opening was played by Emanuel Lasker in 1892. The name derives from a 1904 tournament in Cambridge Springs, Pennsylvania in which the defense was used several times. Practitioners of the opening have included Efim Bogoljubov, Vasily Smyslov, and Garry Kasparov.

The line remains popular among amateurs because there are several traps White must avoid. For example, 7.Nd2 Bb4 8.Qc2 0-0 9.Bd3?? dxc4! (threatening ...Qxg5) 10.Bxf6 cxd3! (a zwischenzug) 11.Qxd3 Nxf6 and Black has won a piece.

Representative game

Capablanca - Alekhine, World Championship Match, Buenos Aires, 1927

1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 Nbd7 5.e3 c6 6.Nf3 Qa5 7.Nd2 Bb4 8.Qc2 dxc4 9.Bxf6 Nxf6 10.Nxc4 Qc7 11.a3 Be7 12.Be2 O-O 13.O-O Bd7 14.b4 b6 15.Bf3 Rac8 16.Rfd1 Rfd8 17.Rac1 Be8 18.g3 Nd5 19.Nb2 Qb8 20.Nd3 Bg5 21.Rb1 Qb7 22.e4 Nxc3 23.Qxc3 Qe7 24.h4 Bh6 25.Ne5 g6 26.Ng4 Bg7 27.e5 h5 28.Ne3 c5 29.bxc5 bxc5 30.d5 exd5 31.Nxd5 Qe6 32.Nf6+ Bxf6 33.exf6 Rxd1+ 34.Rxd1 Bc6 35.Re1 Qf5 36.Re3 c4 37.a4 a5 38.Bg2 Bxg2 39.Kxg2 Qd5+ 40.Kh2 Qf5 41.Rf3 Qc5 42.Rf4 Kh7 43.Rd4 Qc6 44.Qxa5c3 45.Qa7 Kg8 46.Qe7 Qb6 47.Qd7 Qc5 48.Re4 Qxf2+ 49.Kh3 Qf1+ 50.Kh2 Qf2+ 51.Kh3 Re8 52.Qc6 Qf1+ 53.Kh2 Qf2+ 54.Kh3 Qf1+ 55.Kh2 Kh7 56.Qc4Qf2+ 57.Kh3 Qg1 58.Re2 Qf1+ 59.Kh2 Qxf6 60.a5 Rd8 61.a6 Qf1 62.Qe4 Rd2 63.Rxd2 cxd2 64.a7 d1=Q 65.a8=Q Qg1+ 66.Kh3 Qdf1+ 0-1 (67. Qg2 Qh1#)

References

*Hooper, David and Kenneth Whyld. "Cambridge Springs Defence." "The Oxford Companion to Chess"Oxford: Oxford University Press, 1992. 66.