ECO D40 · Queen's Gambit Declined
Queen's Gambit Declined: Semi-Tarrasch Defense
The position after 1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 c5.
1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c5
Queen's Gambit Declined: Semi-Tarrasch Defense is filed under ECO D40, a variation of Queen's Gambit Declined. It is the position after 1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 c5 — 8 half-moves in, with White to move. From here theory names one continuation, Bg5.