comment: This allows Black to play f7-f5.
context: 1. b2b4 A logical initial move, opening the way for the queen and attacking the weakest point of the position. In the conventional chess initial position this point is f7, but in this position it's g7. The problem with this move is that it allows quick counterplay with …a7-a5. 1... b7b5 Black decides to copy White's first move, a generally valid strategy, but in this case it's not the best one. 2. f2f3 This move seems a bit timid, but it's necessary to prepare development and getting the pawn to f4 seems doubtful with a black queen on a8. The best move for White, however, is to open the queenside with 2... d7d6 This move is strange, as it doesn't help Black's position in any visible way. 3. a2a4  3... b5a4  4. a1a4 White could postpone the capture and start with 4... c8b6  5. a4b5  5... a7a6  6. b5g5 The wrong square. 6... h7h6  7. g5g4 Once again a different square than I expected. 7... g8h7  8. c1d3  8... f8h8 Black has managed to finish development and has a good position. The small weakness on a6 isn't important, compared to the benefits of the position, mainly the chance to start a pawn push in the center. 9. b1a2  9... e7e5 Too early. It's better to prepare the advance more carefully, starting with 9...Ba7 or 9...Kh8. 10. g1b6 A good move to finish development and to gain control off the d5-square. 10... c7b6  11. d1c3  11... d8e6 