This is forced.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... a7a6  4. b5a4  4... g8f6  5. b1c3  5... f8c5  6. a2a3 A curious move, with the idea of opening the way for the bishop on a2. But it seems a bit slow. 6... e8g8  7. d2d3  7... c6d4 [%c_effect d4;square;d4;type;GreatFind;persistent;true] Kosteniuk reacts very well. This refutes White's opening play. 8. f3d4  8... e5d4 [%c_effect d4;square;d4;type;GreatFind;persistent;true] 9. c3e2  9... d7d5 