Eventually we will all play our last chess game. Emil Josef Diemer died over 20 years ago. Tom Purser met Diemer and corresponded with him. Here is Tom Purser's announcement in his BDG WORLD, October 1990 and two quotes from BDG WORLD, January 1991:
Emil Josef Diemer 1908-1990
"We deeply regret to report the death of Emil Josef Diemer on October 10, 1990. A remarkable and unique personality is gone, and chess is much the poorer for it. We received the news just before sending this issue to the printer, much too late to include more than this brief notice. Our December issue will be dedicated to the life and chess of E.J. Diemer." [the next BDG WORLD issue ended up being January 1991]
From Schach Echo
"on 10 October the well-known Baden chess theoretician and tournament player, Emil Josef Diemer, died n south Baden Fussbach at the age of 82. ...born on 15 May 1908 in Bad Radolfzell ... work best known to many gambit friends... contributed authoritatively through his exploration of the Blackmar-Diemer Gambit."
From Schach Magazin 64
"In Emil Josef Diemer one of the last 'chess originals' left us. In chess generally and in gambit play especially, to which he dedicated his entire life, his ardent, shining life was fulfilled."
Here is the last known game Emil Josef Diemer played the BDG Ryder Gambit. Most greedy computers back then did not analyze deep enough to consistently defeat masters.
My Blackmar-Diemer Tactics with 500 combinations and mates.
Diemer - Mephisto, Fussbach, Germany 1990 begins 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Qxf3 Qxd4 6.Be3 Qh4+ 7.g3 Qg4 8.Qg2 [Keeping the queen, aiming at b7 and avoiding a future ...Ng4 fork on Be3 and Qf2.] 8...e5 9.Nf3 Bd6 10.h3 Qf5 11.0-0-0 Nc6 12.Bd3 [12.g4 Qd7 13.Bc4 0-0 14.Ng5= is an alternative.] 12...Qe6 13.Ng5 Qe7 14.Bc4 0-0 15.g4 h6 [A complicated position. 15...Bc5 16.Bd2 Nd4 17.Nce4 Ne6 18.Bxe6 Bxe6 19.Nxe6 fxe6 20.Nxc5 Qxc5 White has some compensation for the double sacrificed e-pawns. 21.Qxb7 Rab8=/+] 16.h4 [16.Nge4 Nxe4 17.Qxe4 Be6 18.Bd3 f5! 19.gxf5 Bxf5 20.Qg2 Bxd3 21.Rxd3 Qe6-/+] 16...hxg5? [Taking this knight is fatal. The modern day Houdini 3 points out that Black has 16...Nxg4! 17.Qe4 Nf6 18.Qg6 Be6 19.Bxe6 fxe6-+ and White does not have enough compensation for three pawns.] 17.hxg5 Nxg4 [Sharp to the end, Diemer has a forced mate in seven and finds his way correctly.]