1. e4 e6 2. d4 d5 3. c4 dxe4 4. Be3 Nf6 5. Nc3 b6 6. f3
6. Qc2 Bb7 7. Nge2 Nbd7 8. O-O-O c5 9. Ng3 cxd4 10. Bxd4 Qc7 11. Kb1 Be7 12. Ngxe4 =, Heikkinen - Walkenhorst, corr. 1996. But White must play active, and f3 is the move in the spirit of Diemer.
6... Bb7 7. fxe4 Nxe4 8. Nxe4
I had planned 8. Qf3, hoping for 8... Qh4+ 9. g3 Nxg3? (9... Qf6) 10. Qxb7 Rxh1+ 11. Kd1 +/-, but Black can play simply 8... Bb4 with good game. In other words, the whole idea of fxe4 looks wrong.
8... Bxe4 9. Nf3 Bb4+ 10. Kf2 Be7 11. Bd3
This was a difficult decision. In addition to the queen, the king's bishop is the most useful piece in attacking the Black king, but what else could White do here. After the exchange of bishops, White's only compensation for the pawn is the half-open f-file, which is not much. Black should be very happy in this position.
11... Bxd3 12. Qxd3 Nd7 13. Rad1
I looked for desperate attacks like 13. h4 O-O 14. Ng5 Nf6 15. Raf1 h6 16. Kg1, but after all, there are no real threats.
13... O-O 14. Rhf1 Nf6 15. Kg1
15. Ne5 Bd6 16. Qe2 Ne4+ 17. Kg1 f5 -/+.
15... Nd7
It somehow gives more hope when the opponent moves his pieces back and forth. I am not the only one without a plan...
16. Bf4
16. c5!? bxc5 (16... Nf6 17. Ng5 threatening Rxf6) 17. dxc5 Nxc5 (17... Bxc5?? 18. Bxc5 Nxc5 19. Qa3 wins a piece) 18. Qc2 Nd7 19. Ne5 Bd6 20. Nc6 Qh4!? with unclear game.
16... Bf6
16... Bd6? 17. Ng5 g6 (17... Nf6?? 18. Bxd6 cxd6 19. Rxf6) 18. Qh3 h5 looks nice for White.
17. b4
17. g4 c5 18. d5 e5, but not 18... Bxb2?? 19. dxe6 Nf6 20. Qe2 +-.
17... Qe7 18. c5
I was almost satisfied with 18. Qd2, perhaps intending g4 and g5, but as soon as I found this nice blocking move, I liked it more and more. White already has a clear space advantage, and this just makes more space.
18... Rfc8
18... bxc5 leaves Black's c-pawn lonely. On the other hand, a rook just defending a pawn is not a good idea.
19. g4
This is bold. If you cannot attack, push!
19... g6
I first though that 19... g5 might be better, but White could soon play h4, and the opened kingside would favour White.
20. g5 Bg7 21. c6 Nf8
After 21... Nb8 22. b5, black's knight would remain on b8 forever! On the other hand, there are no moves from f8, either. White's "plan" has been very simple but also effective: b4, c5, g4, g5, c6.
Not Lost in Space, but Lost Without Space
22. h4!
Instead of 22. b5 a6, I first planned to play 22. a3, so that 22... a5 could be met by 23. b4, keeping the a-file closed. Fortunately, I soon realized how close Black's position is to zugzwang; Rd8 may be the only move that would improve (and only a bit) Black's position.
22... Qxb4
"I usually don't mind playing cramped positions, but this is awful!", Sutton wrote. Now the rest is simple because Black queen leaves the battleground.
22... f5! 23. gxf6 Bxf6 is probably the only way to prolong the game. 24. Bg5 looks still promising.
23. Be5 Qa4
23... Re8 24. Bxg7 Kxg7 25. Ne5 Re7 26. Qf3 is crushing.
24. Bxg7 1-0
24... Kxg7 25. Ne5 wins easily. "You have upheld the honor of your gambit!", Sutton wrote. This was my first win in a DDG e-mail game as White. White only had the half-open f-line, but this time it was enough. This is not an easy position for a computer to analyse. Genius 2 with its claimed Elo 2350 believed quite a while that the position is even! Only after a few minutes, it began to raise White's score dramatically.