The Tarrasch Defense is a chess opening characterized by the opening moves 1.d4 d5 2.c4 e6 3.Nc3 c5, although White often plays 3.Nf3 on his third move instead, following up with Nc3 soon afterwards. The Tarrasch is a variation of the Queen's Gambit Declined.

With his third move, Black makes an aggressive bid for central space. After White plays cxd5 and eventually dxc5, Black will often be left with an isolated pawn on the d-file. Such a pawn may be weak since it is undefended by other pawns, but it also grants Black a foothold in the centre.

The opening is named after and was advocated by the German master Siegbert Tarrasch who enjoyed the mobility that Black received, even at the cost of suffering the isolated pawn. Although many other masters rejected the Tarrasch Defense because of the pawn weakness, Tarrasch continued to play this opening and rejected other variations of the Queen's Gambit, even to the point of putting question marks on routine moves in all variations except the Tarrasch (which he awarded an exclamation mark) in his book Die moderne Schachpartie.

The Tarrasch is considered sound. Even if Black fails to make use of his mobility and winds up in an endgame with his isolated pawn, he may still be able to hold a draw if he defends accurately.

In the Encyclopedia of Chess Openings, the Tarrasch Defense has codes D32-D34.

Variations

When White plays against the Tarrasch, the most common setup is to fianchetto his king's bishop in order to put pressure on blacks isolated d5-pawn. Black's 3...c5 has ruled out any possibility of blocking such a fianchettoed bishop by means of ...c6.

The variation 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 c5 5.cxd5 Nxd5 is called the Semi-Tarrasch Defense. Unlike the regular Tarrasch, Black does not suffer an isolated pawn, but he cedes a spatial advantage to White.