The c3 Colle is suitable for beginners. It establishes a d4-pawn in the center and has easy to understand plans. Like the c3 Colle, the London System is an opening system. Opening systems are good for beginners because they do not often require adapting to opponents’ moves. Still, White must always be paying attention to Black’s moves.
According to a Chess.com forum post:
A “System” opening, normally for the player with the White pieces, is a series of beginning moves that leads to a certain opening formation. Usually you don’t have to react to what your opponent is doing.
The ideal positions after the initial moves are as follows for each system.
The c3 Colle ideal position:
The London System ideal position:
White achieves these ideal positions against most opponents.
White’s systems must adapt against certain moves by Black. Black disrupts the c3 Colle by playing the Stonewall Dutch or by playing …d5 and …Bg4. Since a goal of c3 Colle is to play e4, the Stonewall Dutch, with its pawn on f5 and d5, stops that goal. White should instead push c4, sometimes switching to a b3 Colle which was highlighted in a previous article. Against …Bg4, White completely switches gears.
Black disrupts the London System by targeting the bishop on f4 by 3…Bd6. If White does not react, Black doubles White’s f-pawns with …Bxf4. The doubled f-pawns would be weak. Therefore, White plays either Bxd6 or Bg3. Later, Black may threaten …Qb4+ winning the b2-pawn. Here are lines White can play to deal with Black’s disruptions.
These exceptions show that White cannot blindly follow opening systems. White must pay attention to Black’s moves. Thanks to my son William Root, who often taught these lessons to his chess students.