The Queen's Gambit is a chess opening that starts with the moves

1.d4 d5

2.c4

The Queen's Gambit is one of the oldest known chess openings, as Lucena wrote about it in 1497 and it is mentioned in an earlier manuscript in Göttingen. During the early period of modern chess queen pawn openings were not in fashion, and the Queen's Gambit did not become common until the 1873 tournament in Vienna. As Steinitz and Tarrasch developed chess theory and increased the appreciation of positional play, the Queen's Gambit grew more popular. It reached its peak popularity in the 1920s and 1930s, and was played in 32 out of 34 games in the 1934 World Chess Championship. Since then Black has increasingly moved away from symmetrical openings, tending to use the Indian defenses to combat queen pawn openings. The Queen's Gambit is still frequently played, however, and it remains an important part of many grandmasters' opening repertoires.

With 2.c4, White threatens to exchange a wing pawn (the c-pawn) for a center pawn (Black's d-pawn) and dominate the center with e2-e4. This is not a true gambit since if Black accepts the pawn he cannot expect to keep it. An opening trap after 1.d4 d5 2.c4 dxc4 goes 3.e3 b5? (Black tries to guard his pawn but should develop with e.g. 3.Nf6) 4.a4 c6 5.axb5 cxb5?? 6.Qf3! winning a piece on Black's weakened queenside.

The Queen's Gambit is divided into two major categories based on Black's response: The Queen's Gambit Accepted (abbr. QGA) and the Queen's Gambit Declined (abbr. QGD). In the QGA, Black plays 2...dxc4, temporarily giving up the center to obtain freer development. In the QGD, Black holds the center at d5. Frequently Black will be cramped, but Black aims to exchange pieces and use the pawn breaks at c5 and e5 to free his game.

Main variations

After 1.d4 d5 2.c4,

• 2...dxc4 (Queen's Gambit Accepted) (QGA)
• 2...Nc6 (Chigorin Defense)
• 2...c5 (Symmetrical Defense)
• 2...c6 (Slav Defense)
• 2...e5 (Albin Counter Gambit)
• 2...e6 (Queen's Gambit Declined) (QGD)
• 2...Nf6 (Marshall Defense)

Technically, any Black response other than 2...dxc4 (or another line with an early ...dxc4 that transposes into the QGA) is a Queen's Gambit Declined, but the Slav, Chigorin Defense, and Albin Counter Gambit are generally treated separately. In fact there are so many QGD lines after 2...e6, that many of them are distinctive enough to warrant separate treatment. The Orthodox Defense and the Tarrasch Defense are two important examples. See Queen's Gambit Declined for more.

The Slav Defense is a solid response, although many variations are very tactical. If Black plays both ...c6 and ...e6 (in either order), the opening takes characteristics of both the Slav and the Orthodox Defense and is classified as a Semi-Slav Defense .

The Chigorin Defense is unusual, but it appears to be playable for Black.

The Albin Counter Gambit is a sharp attempt for Black to gain the initiative. It is not common in top-level chess, but it can be a dangerous weapon in club play.

The Symmetrical Defense is very rarely played. Although it hasn't been definitely refuted, play seems to favor White.

If White chooses to fianchetto his king's bishop, the game transposes into the Catalan Opening.

The Marshall Defense is the weakest of the Black replies listed. Definitely inferior, Marshall played it for a while in the 1920s before abandoning it.