A position typical for the Reti opening arose,  with reversed colors.
1. d2d4  1... g8f6  2. g1f3  2... g7g6  3. c1f4  3... f8g7  4. e2e3  4... d7d6  5. h2h3  5... c7c5  6. b1d2 The London  system has the practical advantage of developing the pieces in a  conventional way, no matter which opening the opponent chooses. 6... c5d4  7. e3d4  7... e8g8 