Tarrasch Variation, Closed Variation, Main Line

The exchange 7...cxd4 8. cxd4 opens the c-file and frees b4 and b6 for Black's pieces. It also leaves d4 defended only by pawns, so White's knights stay tied to it; recapturing 8. Nxd4 instead would drop e5. The engine sees a slight White edge. The line goes back to 19th-century practice, and Tarrasch himself played it.

The principal reply, chosen in over half of games, is 8...f6, hitting the base of the chain. Here 9. Nf4 runs into 9...Nxd4, so White normally plays 9. exf6 Nxf6 10. Nf3 Bd6 11. O-O. After 11...O-O 12. Bf4, White trades off Black's good bishop, while 11...Qc7 12. Bg5 is the other main path. The second option is 8...Qb6 9. Nf3, which pressures b2, though the pawn is frequently poisoned. Taking it with 9...Qb4+ 10. Bd2 Qxb2 11. Rb1 hands White a strong initiative on the open queenside, so 9...Bb4+ and 9...f6 are the usual choices. The quieter 8...Be7 scores poorly for Black, and 8...Nb6 is the Leningrad Variation.