Diemer-Duhm Gambit

The Diemer-Duhm Gambit is a variation of the French Defense and is characterized by the moves

1. e4 e6
2. d4 d5
3. c4

The Diemer-Duhm Gambit is also a variation of the Blackmar-Diemer Gambit declined with the move order 1.d4 d5 2.e4 e6 3.c4.

The opening is named after the German master Emil Josef Diemer and the German-Swiss master Andreas Duhm.