C31Black4 book lines continue
Falkbeer Countergambit, Nimzowitsch-Marshall Countergambit
King's Gambit Declined1. e4 e5 2. f4 d5 3. exd5 c6
Also known as KGD: Falkbeer, Marshall/Nimzowitsch Countergambit, King's Gambit, Falkbeer Countergambit, Nimzowitsch-Marshall Countergambit, King's Gambit, Falkbeer Countergambit.