1. d4 e6 2. e4 d5 3. c4 dxe4 4. Nc3 Nf6 5. f3 Nc6 6. Be3 Bb4 7. Qb3
Threatening directly the bishop, and indirectly the b7-pawn. From b3, the queen can move quickly to kingside.
7. Qc2 is the main alternative. From c2, the queen threatens directly e4, and indirectly h7. If Black played h6, the queen could move to d2, threatening the efficient bishop sacrifice on h6.
7... O-O 8. O-O-O exf3 9. gxf3
The half-open g-file looks very promising. 9. Nxf3 could transpose to either of the following games in which White actually played Qc2 instead of Qb3:
9... b6?!
This is dubious. 9... Bxc3 would prevent the nasty d5-advance.
10. d5 exd5 11. Nxd5
11. cxd5 Qe7! (11... Bxc3 12. dxc6 wins a piece) 12. Bg5 Na5 13. Qc2 is OK for Black.
11... Bd6
11... Nxd5?? 12. cxd5 wins a piece, and 11... Be7?? 12. Nxf6+ wins the queen.
12. Bg5 Kh8
And the castle is about to break. There were not much choices, though.
13. Nxf6 gxf6 14. Qc3 Kg8
A crazy alternative was 14... Bf5?! 15. Bxf6+ Kg8 16. Bxd8 Bf4+ 17. Rd2 Raxd8, and it is not clear whether White has a sufficient defence. For example, 18. Qb3? Bxd2+ 19. Kd1 Bg5+ 20. Ke1 Bh4+ -+.
15. Bh6
15. Bxf6!? Bf4+ 16. Kc2 Bf5+ 17. Bd3.
15... Bf5
Black nicely utilizes White's weak queenside castling. The whole on c2 is dreadful.
16. Ne2
16. Bxf8?? Bf4+.
16... Re8 17. h4
17. Rg1+ looks a winner: 17... Bg6 18. h4 Kh8 19. h5 +- because of 19... Bf5 20. Bg7+ Kg8 21. Bxf6+.
17... Kh8 18. Rg1 Nb4 19. Qb3 Bc5 draw
Interesting is 19... Bc2!? 20. Bg7+ (20. Qxb4!? Bxd1 is unclear) Kg8 21. Bxf6+ (21. Bh6+ is draw by repetition) Kf8 22. Bxd8 Bxb3 23. axb3 Raxd8 -/+.
White was now happy to repeat with 20. Bg7+ Kg8 21. Bh6+ because 21. Bxf6+ does not give any benefit: 21... Bxg1 22. Bxd8 Be3+ or 22. Rxd8 Raxd8 23. Bxd8 Be3+. White's king position is too open. (Pätzold)
Was this tense or what? I would have watched the fireworks with pleasure:
20. Rxd8 Raxd8 21. Rg3 Re3