Semi-Tarrasch Defense

The Semi-Tarrasch arises when Black meets the Three Knights Variation with 4...c5. The difference from the Tarrasch Defense is that Black plans to answer cxd5 with ...Nxd5 rather than ...exd5, giving up some central presence in exchange for a structure without an isolated d-pawn. The engine rates the position as roughly balanced. The most popular reply is 5. Bg5, the Pillsbury Variation, ahead of 5. cxd5 and 5. e3.

After 5. cxd5 Nxd5 White may play 6. e3 Nc6 7. Bd3, the Main Line, or take the center with 6. e4 in the Exchange Variation. There, 6...Nxc3 7. bxc3 cxd4 8. cxd4 hands White a mobile pawn pair on d4 and e4, while Black counts on pressure against it from the queenside and the half-open c-file; Ding Liren, Giri, Kramnik and Carlsen have all played this line. Recapturing with 5...cxd4 6. Qxd4 exd5 7. e4 dxe4 8. Qxd8+ Kxd8 leads instead to the Endgame Variation, a queenless position with a drawish reputation that has been compared to the Berlin endgame and adopted by elite players seeking a draw. The quieter 5. e3 Nc6 6. Bd3 Bd6 7. O-O O-O produces the Symmetrical Variation. The Semi-Tarrasch can also be reached from the Exchange Variation of the Queen's Gambit Declined after 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 c5 7. Nf3.