Chigorin Defense

The Chigorin Defense is a chess opening named for 19th century Russian master Mikhail Chigorin. An uncommonly played defense to the Queen's Gambit, it begins with the moves:
The Chigorin Defense violates several classical principles: Black does not maintain the center pawn at d5, the c-pawn is blocked, and Black must be willing to trade a bishop for a knight. In return Black gets quick development and piece pressure on the center.
Although opening assessments change as improvements are found for each side, the Chigorin is generally considered playable for Black and it is useful as a surprise weapon against the Queen's Gambit. Alexander Morozevich is perhaps the only modern grandmaster who regularly plays the Chigorin Defense, although in the 1980s, Vasily Smyslov did employ the opening against Garry Kasparov achieving a draw. Morozevich has also published a book on the Chigorin Defence, in which he gives both a theoretical and a personal view on the opening.
Main variations.
The Chigorin Defense has the ECO classification D07.
Because the Chigorin is an unusual defense, the theory of this opening is not as well developed as that for more popular openings.
After 1.d4 d5 2.c4 Nc6 some of the most commonly played variations are: