Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...a6/4. Ba4/4...Nf6/5. O-O/5...Be7/6. Re1/6...b5/7. Bb3/7...O-O/8. c3/8...d5

Marshall Gambit
a b c d e f g h
8a8 black rookb8 black kingc8 black bishopd8 black queene8 black kingf8 black rookg8 black kingh8 black king8
7a7 black kingb7 black kingc7 black pawnd7 black kinge7 black bishopf7 black pawng7 black pawnh7 black pawn7
6a6 black pawnb6 black kingc6 black knightd6 black kinge6 black kingf6 black knightg6 black kingh6 black king6
5a5 black kingb5 black pawnc5 black kingd5 black pawne5 black pawnf5 black kingg5 black kingh5 black king5
4a4 black kingb4 black kingc4 black kingd4 black kinge4 white pawnf4 black kingg4 black kingh4 black king4
3a3 black kingb3 white bishopc3 white pawnd3 black kinge3 black kingf3 white knightg3 black kingh3 black king3
2a2 white pawnb2 white pawnc2 black kingd2 white pawne2 black kingf2 white pawng2 white pawnh2 white pawn2
1a1 white rookb1 white knightc1 white bishopd1 white queene1 white rookf1 black kingg1 white kingh1 black king1
a b c d e f g h

Ruy Lopez, Marshall Gambit

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Black is attacking e4 twice and in general threatening to overrun the centre of the board. White has no better option than to accept the proffered pawn with

followed by capturing twice on e5. Skip ahead to the end of that forcing variation if you like: 9. exd5 Nxd5 10. Nxe5 Nxe5 11. Rxe5.

However, White can also decline the gambit with 9.d4.