White found an improvement at move 15 in a rare sideline given in my Blackmar-Diemer Theory 3 book. The opening is a BDG Teichmann Seidal-Hall variation where White gambits a second pawn. I gave 15.Re1 at the end of my analysis. Better is 15.Bxb8! which wins material in the game Baptiste Alloui-Cros vs Timothy Jin Sheng Ling.
My Blackmar-Diemer Tactics with 500 combinations and mates.
Alloui-Cros (2130) – Ling (1640), FIDE World Uni RapidD Tornelo, 21.03.2021 begins 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bg4 6.h3 Bxf3 7.Qxf3 c6 8.g4 Qxd4 9.Be3 Qe5 [9...Qb4 10.0–0–0= White has excellent play for the two gambit pawns.] 10.0–0–0 e6 11.g5 Nd5 [11...Nfd7 12.Be2=] 12.Nxd5 cxd5 13.Bf4 Qe4 14.Qxe4 dxe4
15.Bxb8! [Years ago I suggested 15.Re1 but it seems Black is fine after 15...h6 16.Rxe4 hxg5 17.Bxg5 Nc6 18.Bg2 though White has some compensation for the gambit pawn.] 15...Rxb8 16.Bb5+ Ke7 17.Rd7+ Ke8 18.Rxb7+ [White wins a rook with this move. Another good idea is 18.Rhd1 winning. For example, 18...a6 19.Rd8+ Ke7 20.R1d7#] 18...Kd8 19.Rxb8+ Kc7 20.Ra8 Kb7 21.Re8 h6 22.g6 fxg6 23.Rf1 a6 24.Ba4 1–0
