Back To The Drawing-Board?

I HAVE been trying an unusual line against the Petrov: 1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nf3 Nxe4 5.c4!?

Position after 5.c4!?

It is recommended by Larry Kaufman in The Chess Advantage In Black And White (McKay, 2004).
He writes: "It is closely related to the slightly more fashionable 5.Nc3, as both moves can lead to doubled c pawns, but it has the advantage that White is only obliged to permit the doubling when Black plays ...Nc6 first, after which the knight is poorly placed in relation to a white pawn on c3, or when he plays ...c6, which permits White to annoy the d6 pawn."
My first two outings with the line were correspondence games in which I beat a 1332 and drew with a 2458. More recently I have played it in four over-the-board games, winning all four.
Admittedly those four games were against opponents I would have been expected to beat, but nevertheless I had no reason to be dissatisfied with the line.
Then came the following correspondence game:
Spanton (2260 - England) - Nick Flew (2000 - Wales 2)
Carlos Flores Gutiérrez Team Tournament (ICCF) 2020

1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nf3 Nxe4 5.c4!? Nc6

All my previous games, except for the draw against Noire, featured 5...Be7. That is the most popular move in ChessBase's 2020 Mega database, but it allows 6.d4, which is not the end of the world for Black but does give White good central control.

6.Nc3!? Nxc3 7.dxc3

This is the main line but also possible is 7.bxc3!? followed by a quick d4 with the idea of central control.

7...g6!?

Kaufman only covers 7...Be7 and 7...Bg4. The text is slower but, based on this game at least, seems perfectly playable, in which case it is hard to see what the line offers White.

Spanton (2158) - Eric Noire (2458), IECG World Championship Semi-Final 2007, went 7...Bf5!? 8.Nd4 Nxd4 9.Qxd4!? Qe7+ 10.Be3 Qe5 11.0-0-0 Be7 12.Bd3 Qxd4 13.Bxd4 Bxd3 14.Rxd3 f6 (½–½, 30 moves).

8.Bg5 Be7 9.Bh6!?

This was played in all seven Mega20 games to reach this point.

9...Bf8 10.Be3

Gawain Jones (2640) - Shakhriyar Mamedyarov (2804), Tata Steel A (Wijk aan Zee) 2018, saw 10.Bg5 Be7 11.Bh6 Bf8 12.Bg5 ½–½.

10...Bg7 11.c5!?

This may be new. 11.Qd2 is the known continuation.

11...dxc5 12.Qxd8+ Nxd8 13.Bxc5

White's position looks promising at first glance as Black has trouble castling kingside, but this proves a minor inconvenience.

13...a6 14.Bc4 Be6 15.Bb3 Bxb3 16.axb3 Ne6 17.Be3 0-0-0 18.0-0

Opposite-side castling with a half-open a file would lead to a sharp game with queens on, but here the game fairly quickly peters out.

18...Rd5 19.b4 Rb5 20.Nd2 Bf6 21.g3 Rd5

We played a further 15 moves, but the equilibrium never looked like being disturbed, which is rather disheartening from a white perspective.

Admittedly this was a correspondence game, and it would not be so easy (for either player) to play as accurately OTB, but it seems I will need to find a radical wrinkle if I wish to continue playing 5.c4!? with serious prospects of a gaining an advantage against a prepared opponent.