The Main Line is a variation of the London System, with Be2, catalogued as ECO A48. The line runs 1. d4 Nf6 2. Nf3 g6 3. Bf4 Bg7 4. e3 d6 5. Be2 O-O, reaching the position shown below after 10 half-moves.
White holds the centre with pawns on d4. Development is level at three minor pieces each. It is White to move after five moves. Black has castled while White’s king is still uncommitted.
On the London System, with Be2 generally: ECO A48. A chess opening with 3 known variations.
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 3 London System, with Be2 variations →
The Main Line goes 1. d4 Nf6 2. Nf3 g6 3. Bf4 Bg7 4. e3 d6 5. Be2 O-O. It is a variation of the London System, with Be2 and is catalogued as ECO A48.
The Main Line is ECO A48. ECO codes group openings by their move order, so nearby codes cover closely related lines of the London System, with Be2.
Stockfish evaluates the position after 1. d4 Nf6 2. Nf3 g6 3. Bf4 Bg7 4. e3 d6 5. Be2 O-O at +0.17 at depth 18, which is balanced. 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.
White holds the centre with pawns on d4. Development is level at three minor pieces each. It is White to move. Black has castled while White’s king is still uncommitted.