https://www.theguardian.com/sport/2025/ ... llegations
That looks parallel to an idea that someone has done youtube videos on. This runs 1. e4 e5 2. Nf3 Nc6 3. Bc4 f5. Now 4. exf5 allows 4. .. e4 and Black is somewhat better. Despite the advocacy of its presenter, both 4. d4 (reverse Vienna) and 4. d3 (reverse Kings Gambit declined) seem storng. The extra tempo does help with the tactics, particularly those based around Ng5 because of the Bishop already on c4.Barden in the Guardian wrote:In round seven, against his then co-leader Niemann, Caruana produced the game of the tournament, a sensational display of original strategy. After the sequence 1 e4 e5 2 Nf3 Nc6 3 Bc4 d6 4 c3 f5!? 5 d3 Qf6! White should play 6 exf5! or 6 Ng5 keeping the position open and his forces mobile. After 6 0-0? f4! it is already strategically difficult as Black’s Qf6 is active.
If you look at the Caruana idea with colours reversed, say by starting 1. e4 e5 2. f4 Bc5 3. Nc3 d6 4. d3 Nf6 5. Qf3, you run into the problem that Black won't obligingly play 5. .. c6, but .. Nc6 instead.
I could suppose that Mestel's 1970s line in the Philidor of 1. e4 e5 2. Nf3 d6 3. d4 f5 is also related.