French Defense: Tarrasch Variation, Open System

The Open System of the Tarrasch Variation is 1.e4 e6 2.d4 d5 3.Nd2 c5, Black's way of breaking open the centre at once against 3.Nd2 in the French Defense. White's most common reply is 4.exd5, followed by 4.Ngf3.

After 4.exd5 exd5

This recapture was a staple of many games between Anatoly Karpov and Viktor Korchnoi, including seven games in their 1974 Candidates match. It usually leaves Black with an isolated queen's pawn. The main line continues 5.Ngf3 Nc6 6.Bb5 Bd6 7.O-O Ne7 8.dxc5 Bxc5 9.Nb3 Bb6. If White can neutralise the activity of Black's pieces in the middlegame, White will have a slight advantage in the ending. White can also play 5.Bb5+ Bd7 6.Qe2+ Be7 7.dxc5, trading bishops and making it harder for Black to regain the pawn.

After 4.exd5 Qxd5

4...Qxd5 trades Black's c- and d-pawns for White's d- and e-pawns, leaving Black with an extra centre pawn. This is a slight structural plus, but White gains time by harassing the queen, and that mix of static and dynamic factors has made the line popular. Play usually continues 5.Ngf3 cxd4 6.Bc4 Qd6 7.O-O Nf6 8.Nb3 Nc6 9.Nbxd4 Nxd4, and White either keeps the queens on with 10.Nxd4, far more common today, or offers a trade with 10.Qxd4.

Other fourth moves

4.Ngf3 has been played by Paul Keres and Max Euwe and is still used; it often transposes to the 4.exd5 lines. 4.c3 is possible, but after 4...cxd4 5.cxd4 dxe4 6.Nxe4 Nf6 the position is judged to give White no advantage.

The numbers

On Lichess White wins 49.4% of the 2.3 million games and Black 44.4%. From 2200 up the gap is smaller, 46.9% against 43.9%, with 9.2% drawn. Masters over the board draw half their games: in 15,657 games 50.7% were drawn, White won 29.1% and Black 20.2%.