Threatening to take on d3.
1. g1f3  1... d7d5  2. g2g3  2... g8f6  3. f1g2  3... e7e6  4. e1g1  4... f8e7  5. d2d3  5... e8g8  6. b1d2  6... c7c5  7. e2e4  7... b8c6  8. f1e1  8... b7b5  9. e4e5  9... f6d7  10. d2f1 All this is well known in the King´s Indian Attack. This opening became very popular especially after Bobby Fischer won spectacular games with it. It's attractive because White's moves are schematic, which makes it interesting for fast-paced games, as you know what to do. That said, the attack isn't so easy to execute. 10... d8c7  11. c1f4  11... c8b7  12. h2h4  12... f8c8  13. h4h5  13... h7h6 [%c_effect h6;square;h6;type;GreatFind;persistent;true] It's important for Black to avoid the move h5-h6, which creates weaknesses on the dark squares. There's a price to pay: White can try to sacrifice a piece on h6 or to play g4-g5 at some point. 14. d1d2  14... c6d4 A new move. 15. f3d4  15... c5d4  16. e1e2  16... a7a5 The play becomes very concrete: Black advances the queenside, and White advances the kingside. Whoever arrives first, wins. 17. f1h2  17... a5a4  18. a2a3  18... c7b6 Getting ready to play b4. 19. h2f3  19... b5b4  20. a3b4  20... e7b4  21. d2c1  21... b4f8 [%c_effect f8;square;f8;type;GreatFind;persistent;true] A good move, bringing the bishop to the protection of the king. 22. g3g4 The advance of the g-pawn is White's only meaningful plan.