comment: Considered by theory as the main move to equalize.
context: 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.