As early as July 1874 the Dubuque Chess Journal noted
It should be understood that Mr. Jerome claims in this New Opening "only a pleasant variation of the Giuoco Piano, which may win or lose according to the skill of the players, but which is capable of affording many new positions and opportunities for heavy blows unexpectedly."
The following game serves as a fine example.
Wall, Bill - NN
1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+
8.Nc3 Nf6 9.Bf4
Bill has also played 9.O-O, e.g. in Wall,B - Guest4809124, PlayChess.com, 2013 (0-1, 41) and Wall,B - Guest5111265, PlayChess.com, 2014 (1-0, 48).
9.Bg5 was seen in two unfinished 1881 correspondence games between gambit inventor Alonzo Wheeler Jerome and chess columnist S. A. Charles.
9...Qe7 10.O-O-O Rf8 11.Rhe1 Bg4 12.f3
Black is convinced that he has the advantage (he does) and therefore should be able to unleash an unexpected "heavy blow" himself. At first glance his sacrifice looks scary, but it proves to be his own undoing, not White's.
12...Bxf3 13.gxf3 Nxf3
Black's idea. Now, if, say, 14.Qb4, then 14...Nxe1 15.Rxe1 Rfb8!? looks like the start of a scary attack against White's King.
However, as in the previous blog post, it appears that Black has gone about his business, but has left the water running... He has overlooked something.
The Queen escapes the fork with check.
This move is often the remedy to White's check along the diagonal, but not in this situation. Black should go with 14...Qe6 and after 15.Qxc7+ Kg8 16.Re2 Rf7 17.Qxd6 White will have the advantage - but the game would still be complicated.
Black's game now comes undone.
15.Nxd5 Nxd5 16.Re3 Rae8 17.exd5 Black resigned
Very nice. Black's Knight is hanging, and the discovered check from a possible d5-d6 also looms.