Out-Weird the Jerome Gambit

 

I was going over a recent chess game with an opening that tried to out-weird the Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+): drumme - rajasthan, blitz, FICS, 2023 (1-0, 28) started off 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nb4?!

Say, what?

There is weird, and then there is weird.

I was somewhat comforted by the outcome of the game, especially since the player of the White pieces, drumme, is a longtime Jerome Gambiteer - his games in The Database start in 2008 and continue through 2023.

A closer look at The Database showed 25 games (that many??) with 3...Nb4?! White scored 84%.

I was even more reassured upon encountering an unattributed entry in The Database referring to "A nice trap in a Jerome-type position". Quite possibily, the author was the Australian privite eye, Cliff Hardy, another Jerome Gambit afficiando.

Here it is. I have added diagrams.

1.e4 e5 2.Nf3 Nc6 3.Bc4 Nb4 4.Bxf7+ Kxf7 5.Nxe5+ Ke7 

Black is trying to be tricky - he wants to invite a Jerome player to play the standard Qh5, but after Ke7 this doesn't come with check and then he wants to play Nxc2, winning the rook. 

6.Qf3

This move is significantly better then Qh5 (evaluation: around -1.40 for Qf3, around -3 for Qh5, as Qh5 will be met with Qe8 and black moved his queen to a better place while attacking white queen, who has to retreat, since the exchange of queens strongly favoures black), but Qf3 still allows black to follow his fishy plan (which we should gladly allow him to execute, since this is a "short road to hell" for him).

6...Nxc2+ 7.Kd1 Nxa1 

Black is happy to have a huge material advantage, but there will be a suprise. From now, there is no reverse: this is a forced mate in 6!!!

8.Qf7+ Kd6 9.Nc4+ Kc5 10.Qd5+ Kb4 11.a3+ Ka4 12.Nc3+ Kb3 13.Na5 checkmate 

A nice curiosity: any move with this knight results in mate. A comment at the end: After 6.Qf3, playing 6...Nxc2 is not the best choice: according to Stockfish, there are 3 stronger moves for black: 6...Qe8, 6...Nf6, 6...Nh6, taking on c2 is a fourth line, also reasonably good (evaluation: +1.01 at depth 33), especially in double-edged positions with both kings exposed and especially in shorter time formats. The losing move is, whereas, taking the poisoned rook (losing without reverse, since it's an easy mate with all moves forced). 

After 7.Kd1, black should play 7...Nf6 (the best move, eval. +1.05, developping new piece, white plays KxN and retrieves the sacrificed knight, but for a price of exposing the king) or 7...Qe8 (eval. +1.33, with the same idea) or the inhuman 7...Ne3 (best reply is the obvious QxN, without exposing the king, but the engine likes this for some deeep reason, eval. +1.37). All moves beside these 3 are evaluated at least +2.

Black resigned