1. d2d4  1... g8f6  2. g1f3  2... d7d5  3. c1f4  3... c7c5  4. e2e3  4... b8c6  5. b1d2  5... c5d4  6. e3d4  6... d8b6  7. d2b3  7... c8g4  8. a2a4  8... a7a6 A novelty, which prevents the white a-pawn from  going too far. 9. a4a5 