A novelty, although the advance of the a-pawn is a common theme in the Grunfeld.
1. g1f3  1... d7d5  2. g2g3  2... g7g6  3. f1g2  3... f8g7  4. d2d4  4... g8f6  5. e1g1  5... e8g8  6. c2c4  6... c7c6  7. d1a4 A relatively rare move, championed by Oparin. 7... f6d7 Erigaisi played this without much hesitation. The text move initiates a nice regrouping by Black. 8. a4b3 This and the next few moves were played practically in a blitz tempo by Praggnanandhaa.