1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1c4  3... f8c5  4. c2c3  4... g8f6  5. d2d3  5... d7d6  6. c1g5  6... h7h6  7. g5h4  7... a7a6  8. b1d2  8... c5a7  9. e1g1  9... e8g8  10. a2a4  10... g7g5  11. h4g3 The early sortie of this bishop  is a double-edged sword. It might do a great job pinning the opponent's  knight, but it may end up excluded from the game. At the same time, in  order to force the bishop out of the game Black needs to advance the pawns in front of his king, thus exposing it. 11... g8g7  12. f1e1 White wants  to free his bishop with brute force. The push d3-d4 followed by e4-e5 is a threat.