The standard London System consists of the setup moves: d4, Bf4, e3, Nf3, Nbd2, c3, Bd3. I'm wondering about the nuances of what the most accurate move order is to play it in. Here are some of my thoughts:
Some people like reaching the London via 1.d4 Nf6 2.Nf3, but I like playing 2.Bf4; that way, you can go for the more aggressive setup with 3.Nc3 against King's Indian players, potentially tricking them into a Pirc.
Against people who play symmetrically, ie. 1.d4 d5 2.Bf4 Bf5, I like playing an early c4 instead of c3 to break symmetry.
If White plays Nf3 early, Black can play a combination of Nc6-Nh5 to harass / potentially trap the London bishop (since the queen has lost vision of h5) and force it to move off its natural diagonal, which can be annoying.
[FEN ""] 1.d4 d5 2.Bf4 Nf6 3.e3 c5 4.Nf3 Nc6 5.Nbd2 Nh5
If Black follows the main line setup with d5/Nf6/c5/Nc6/Qb6, it seems more accurate to play Nbd2 before c3, in case Black decides to enter the sharp gambit lines with dxc5 / Qxb2.
- d4 d5 2.Bf4 Nf6 3.e3 c5 4.Nf3 Nc6 5. Nbd2 Qb6 6.dxc5 Qxb2 7.Rb1
In the main line, most masters seem to prefer the move order with d4-Bf4-e3-c3-Nd2; I'm not sure why this is.
- d4 d5 2. Bf4 Nf6 3. e3 c5 4. c3 Nc6 5. Nd2
Why do masters prefer the above move order, and what other nuances am I missing from my points here?