1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. d1c2 A must-win situation for Yu. He  needs to choose as complex lines as possible. 4... e8g8  5. e2e4  5... d7d5  6. e4e5  6... f6e4  7. a2a3  7... b4c3  8. b2c3  8... c7c5  9. c1b2  9... b8c6 