1. e2e4  1... e7e5  2. g1f3  2... g8f6  3. f3e5  3... d7d6  4. e5f3  4... f6e4  5. b1c3  5... e4c3  6. d2c3  6... f8e7  7. c1f4  7... e8g8  8. d1d2  8... b8d7  9. e1c1  9... d7c5 This is by far Black's most common plan. The knight is on an active square, and the light-squared bishop can soon be developed. But there's also a problem: one cannot fail to notice that the knight is far from the king now, and the monarch feels a bit insecure in a situation with castling on different flanks. 10. h2h4 [%c_effect h4;square;h4;type;GreatFind;persistent;true] The most unpleasant reaction. The pawn supports a knight jump to g5. 10... f8e8  11. f3g5 [%c_effect g5;square;g5;type;GreatFind;persistent;true] This is the main idea of White's previous move. It's not easy to live with such a knight nearby, so Black attacks it. 11... h7h6  12. f1c4 [%c_effect c4;square;c4;type;GreatFind;persistent;true] Sacrificing the knight (or bishop) to open the h-file is a well-known idea in chess, already tried in many different openings and defenses. Sometimes it's possible to capture the fearless piece, but this usually involves considerable risk, even if it is possible to defend. Probably surprised with the opening, the young Lee decides to make a major positional concession rather than confront Kosteniuk's home analysis. Probably a good practical decision, although scientifically it's not the best option. 12... c8e6 [%c_effect e6;square;e6;type;Inaccuracy;persistent;true] 13. g5e6 After the capture of the important light-square bishop, it's safe to say that White won the opening battle. But now the middlegame starts. 13... c5e6  14. c4e6 I don't like this move at all. There's no compelling reason to immediately exchange this bishop. 14... f7e6  15. c1b1  15... e8f8  16. d2e3 [%c_effect e3;square;e3;type;Inaccuracy;persistent;true] 16... d8c8 [%c_effect c8;square;c8;type;GreatFind;persistent;true] It's important to remove the queen from the d-file so that Black can play e6-e5. 17. e3e4  17... f8f7 Only this is a new move. 18. c3c4 Preventing the advance d6-d5. 18... a8b8 [%c_effect b8;square;b8;type;Interesting;persistent;true] A clever plan to create some counterplay. 19. f4e3  19... b7b5 [%c_effect b5;square;b5;type;GreatFind;persistent;true] Here it is: Black's first active move in the whole game. But the picture radically changes now. From now on, Kosteniuk loses control of the game. 20. c4b5 [%c_effect b5;square;b5;type;Mistake;persistent;true] A positional mistake, activating Black's rook.