A novelty. Gukesh thought for about 35 minutes before playing it.
1. g1f3  1... g8f6  2. g2g3  2... d7d5  3. f1g2  3... c7c5  4. e1g1  4... b8c6  5. d2d4  5... e7e6  6. c2c4  6... d5c4  7. d1a4  7... c8d7  8. d4c5  8... f8c5  9. a4c4 A well-known position that can arise from several move orders. 9... c5e7  10. b1c3  10... e8g8  11. e2e4  11... a8c8  12. c4e2  12... e7c5 A precise move, played just once before. Giri played it quickly, so he certainly knew the position well.