1. d2d4  1... g8f6  2. c2c4  2... g7g6  3. b1c3  3... d7d5  4. c4d5  4... f6d5  5. e2e4  5... d5c3  6. b2c3  6... f8g7  7. d1a4 The Grunfeld Defense is probably the toughest variation against 1.d4. This move is one of many possible attempts to confuse the opponent. While it's impossible to prove a scientific advantage, at least White can try to pose practical problems. This strategy will succeed in the present game. 7... b8d7  8. g1f3  8... e8g8  9. f1e2  9... d7b6 This is the first important moment for opening theory. 9...c5 is also possible and was played in 2019 in a game of the highest caliber. But the move played is an even better way to equalize. 10. a4b4  10... d8d6 