When you get out-played in a chess game - as I was in the following Jerome Gambit - it is still tempting to look for the one move that set you on the path to defeat. It is more likely, at least in my experience, that there are a number of mistakes, topped by one big one, that leads to a loss.
It is clear, in any event, that my opponent was the better player in this contest.
perrypawnpusher - ZlikoM
"Piano Piano" tournament, Chess.com, 2020
1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+
So far, pretty routine. The Database has 226 games with this position, going back to Charlick - Mann, correspondence, 1881 (1-0, 72).
10.O-O Qe7
Pressure against the e-pawn. I had scored 8 - 1 - 1 against this move, previously. Komodo 11 prefers 10...d5, which has not yet showed up in The Database.
11.Nc3
White has a number of Jerome-ish ideas available to him here, from reinforcing his e-pawn with either 11.d3 or 11.f3, or advancing one of those pawns with 11.f4. The last looks a little iffy, according to Stockfish 11: 11.f4 Nxe4 12.Re1 d5 13.d3 Nd6 14.Qf2 Be6 15.g4 Rf8 16.f5 Nxf5 17.gxf5 Rxf5.
I decided to sidestep all of that and reinforce the e-pawn differently.
11...b6
The Database has 4 games with this position, including perrypawnpusher - navarrra, blitz, FICS, 2011 (1-0, 24), perrypawnpusher - alvarz, blitz, FICS, 2013 (0-1, 59), and perrypawnpusher - MarkHundleby1, "Italian Game" tournament, Chess.com, 2016 (1-0, 27).
12.f4 Bb7 13.f5
A typical Jerome Gambit advance. Stockfish 11 prefers the more solid 13.d3, which I played against alvarz (above) and which transposes to perrypawnpusher - MRBarupal, blitz, FICS, 2010 (0-1, 22).
13...Ne5 14.d4 Neg4
Withdrawing the Knight to f7 would have been more solid, but it is too much of a temptation to attack the White Queen. Certainly Black's pieces appear to be controlling the "Jerome pawns".
15.Qg3 Kd7
Is Black's King safer on the d-file? What will happen when Black's Rooks enter the game? How should White proceed?
[to be continued]