The best move. White shouldn't be in a hurry to capture on e4.
1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. d1c2  4... e8g8  5. e2e4 From time to time, players with White try to exploit the complicated variations that arise from this straightforward move. The problem is that the lines are already well studied, but Keymer certainly had everything very well prepared and the risk is small. 5... d7d5 Considered by theory as the main move to equalize. 6. e4e5  6... f6e4  7. a2a3 A much rarer move than 7.Bd3 and one that had been somewhat forgotten, having not been played at the highest level for some time. Keymer was probably counting on the surprise factor. 7... b4c3  8. b2c3  8... c7c5  9. f1d3  9... c5d4  10. c3d4  10... b8c6  11. g1e2  11... d8a5  12. e1f1  12... f7f6 The most accurate move. 13. d3e4  13... d5e4  14. e5f6  14... f8f6  15. c1e3  15... c8d7 One of many possible moves.