Jerome Gambit: Heavy Blows Unexpectedly

As early as July 1874 it was clear that Alonzo Wheeler Jerome had no illusions about his gambit, as 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."

Indeed. In the following game, Black plays a move that would have been fine as his 10th, but is totally inadequate as his 11th. After his 14th move - he cannot escape checkmate.

Wall, Bill - Guest433702
PlayChess.com, 2017

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+ 

4...Kxf7 5.Nxe5+ Nxe5 6.d4 Bxd4 7.Qxd4 Qe7 

An unusual replacement for 7...d6, although Black has done well with it, according to The Database, which has 24 games - and Black has won 14 of them (White scores 42%). The defender looks even better if you subtract the 4 wins with White (against no losses) that were scored by Bill Wall.

8.Bf4 

White takes a break from castling, which has also been successful for him: 8.0–0 Nf6 (8...c5 9.Qd5+ Qe6 10.Qxc5 Ne7 11.f4 d6 12.fxe5+ Black resigned, Wall,B - Anonymous, lichess.org, 2016) 9.Nc3 c6 (9...Nc6 10.Qd3 Nb4 11.Qc4+ Kf8 12.e5 Nh5 13.f4 Nxc2 14.Nd5 Qe6 15.Qxc7 Nxa1 16.f5 Qxd5 17.Qd8+ Kf7 18.e6+ dxe6 19.fxe6+ Kxe6 20.Re1+ Qe5 21.Rxe5+ Kxe5 22.Qxh8 Nc2 23.Qe8+ Black resigned, Wall,B - Bojovic,D, PlayChess.com, 2017 *This is arguably the best Jerome Gambit game of the year*) 10.f4 Ng6 11.e5 Ng4 12.h3 Nh6? 13.f5 Nh4 14.f6 gxf6 15.exf6 Nf3+ 16.Rxf3 Qe6 17.Bxh6 Rg8 18.Qd3 d5 19.Qxh7+ Ke8 20.f7+ Black resigned, Wall,B - Guest2327120, PlayChess.com, 2014. 

8...d6 9.Nc3 c6 

Aiming to keep White's Knight out of d5, although it weakens his d-pawn, and this becomes an issue as the game develops.

10.O-O-O Ke6

Brave, but probably unnecessary. Black could afford to develop with 10...Nf6 and let the d-pawn go.

11.Rd2 Nf6 

Suddenly, this move is no longer a good idea. The Knight crowds Black's King, and makes it vulnerable to the upcoming Queen check along the a2-g8 diagonal. Black would have done better to retreat his King with 11...Kf7, reserving the e6 square for his Bishop. If White then grabbed a pawn with 12.Qxd6, then 12...Nc4!? would have stabilized the game, e.g. 13.Qxe7+ Nxe7 14.Rdd1 when Black would have his typical piece for two pawns.  

12.Bxe5 dxe5 13.Qc4+ Nd5

He has no choice but to return the extra piece.

14.exd5+ cxd5 15.Nxd5 

Black cannot escape checkmate.

15...Qf7 16.Nc7+ Kf6 17.Qh4+ Kg6 18.Rd6+ Kf5 19.g4+ Ke4 20.Re1+ Kf4 21.Qg3+ Kg5 22.h4 checkmate