von Hennig Gambit

Rather than recovering the pawn with 4. Nxe4, White develops the bishop toward f7 and usually prepares f3 to open the f-file. The play closely resembles the Blackmar-Diemer Gambit. Against the usual 4...Nf6, the standard continuation is 5. f3 exf3 6. Nxf3. Black then chooses among 6...Bf5, 6...e6 and 6...Bg4. The last of these runs into 7. Bxf7+ Kxf7 8. Ne5+, and White wins material. After 6...e6, White follows typical Blackmar-Diemer plans: castling, Qe1-h4 and Bd3. The main line is 6...Bf5 7. O-O e6 8. Ng5 Bg6. The bishop retreat avoids tactics based on Rxf5 and a fork. White can then play quietly with 9. Ne2 or 9. Bf4, or sacrifice with 9. Bxe6 fxe6 10. Nxe6. That sacrifice leaves Black facing a choice between giving up the queen and enduring a very dangerous attack.

The second most common reply, 4...Bf5, can transpose after 5. f3 exf3 6. Nxf3 Nf6. 4...b5 5. Bb3 tends to reach similar play. Engines give Black a slight edge, yet White scores well in the Lichess database. The gambit remains an offbeat choice suited to faster time controls.