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The Marshall Defense is a chess opening that begins with the moves

1.d4 d5

2.c4 Nf6

The Marshall Defense is a dubious variation of the Queen's Gambit Declined. It was played by Frank Marshall in the 1920s, but he gave it up after losing with it to Alekhine at Baden-Baden in 1925. It is no longer used by experienced players.

If White plays e2-e4 too early, Black may equalize (for example, by 3.cxd5 Nxd5 4.e4?! Nf6 5.Nc3 e5! 6.dxe5 Qxd1+ 7.Qxd1 Ng4!). Instead, White gets a clear advantage with 3.cxd5 Nxd5 4.Nf3! Bf5 5.Qb3.

White may also ignore Black's provocative second move, and play 3.Nc3, which will usually transpose into normal lines of the Queen's Gambit Declined (after 3...e6), the Slav Defence (after 3...c6), the Queen's Gambit Accepted (after 3...dxc4) or the Grünfeld Defence (after 3...g6).