The Main Line is a variation of the Stonewall Attack, catalogued as ECO D00. The line runs 1. d4 d5 2. e3 Nf6 3. Bd3 c5 4. c3 Nc6 5. f4, reaching the position shown below after 9 half-moves.
Both sides have pawns in the centre (White on d4, Black on d5), and one pawn capture is available, so the structure has not settled yet. Development is level at one minor pieces each. It is Black to move after five moves.
On the Stonewall Attack generally: White builds a solid pawn wall on d4-e3-f4-c3 with the bishop on d3. A straightforward attacking system aimed at the kingside.
You can play through this variation move by move in your browser — Learn mode walks the line with an explanation at each step, and Drill mode replays it from memory so you find out whether you actually know it. No account is required.
See all 7 Stonewall Attack variations →
The Main Line goes 1. d4 d5 2. e3 Nf6 3. Bd3 c5 4. c3 Nc6 5. f4. It is a variation of the Stonewall Attack and is catalogued as ECO D00.
The Main Line is ECO D00. ECO codes group openings by their move order, so nearby codes cover closely related lines of the Stonewall Attack.
Stockfish evaluates the position after 1. d4 d5 2. e3 Nf6 3. Bd3 c5 4. c3 Nc6 5. f4 at -0.67 at depth 18, which is a small but real edge for Black. Engine evaluation is only a starting point — at club level the practical value of a line is mostly about whether you know its plans better than your opponent does.
Both sides have pawns in the centre (White on d4, Black on d5), and one pawn capture is available, so the structure has not settled yet. Development is level at one minor pieces each. It is Black to move.