ECO D45 · Semi-Slav Defense
Semi-Slav Defense: Main Line
The position after 1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.e3 e6 5.Nf3.
1. d4 d5 2. c4 c6 3. Nc3 Nf6 4. e3 e6 5. Nf3
Semi-Slav Defense: Main Line is filed under ECO D45, a variation of Semi-Slav Defense. It is the position after 1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.e3 e6 5.Nf3 — 9 half-moves in, with Black to move. From here theory names 2 continuations: Nbd7, a6.