Nakamura did not mind repeating a line which Aronian used at the first Grand Prix event that took place in Berlin as well.
1. d2d4  1... d7d5  2. c2c4  2... d5c4  3. e2e4  3... b7b5  4. a2a4  4... c7c6  5. a4b5  5... c6b5  6. b1c3 