Structurally Bxe6 is a very natural move to play because of the constricted pieces. With Re3 he should have had the consolidated idea of playing Bxe6 if Topalov's doesn't defend it . And he didn't !

In the position after 9...Be7 Black is behind in development but has central pawn superiority. White can hardly claim an advantage. Yet he plays an attacking move 10 e5? This attack is unsound then and can be forecast to fail.

12 Qg4? persists in an unsound attack. This increases Black's advantage.

11...Kf8 avoids disturbing the king side pawns but also loses the right to castle. One alternative is 11...g6 getting ready to castle on the queen side. Another interesting alternative is a piece sacrifice: 11...Nxe5 12 Rxe5 Bf6 13 Re1 e5

Instead of 12...Qa5 12...Qc7 places pressure on the e5 pawn

13...h5? disturbs the king side pawns without necessity and is inconsistent. Having given up the right to castle lo less to avoid making this concession, he now makes it.

14...g5? may be a losing mistake. He thinks that he can take over the initiative on the king side.

It is possible that Topalov's plan was based on an oversight and when Topalov saw what he had overlooked it was too late.

Now how does one answer such an attack? Caruana's subsequent play offers some indications of an answer.

17 Qg4 occupies a square left undefended by the pawn storm, the square g4.

19 c4 attacks Black's centre and so transforms it from a weapon into a target.

The American commentators ( Ashley, Seirawan, Shahade) praised the moves 21 h3, 22 Bc3 and 23 Re3 which gain time towards the attack by preparing it and refusing to be drawn into making premature haste

24 Bxe6! begins the attack, the bishop acting in concert with the queen.

<Much of the game was won at home. Caruana's second, GM Vladimir Chuchelov, prepared the move 13. Re2:

"How else to get the bishop to d2?" said Chuchelov.

Although the idea looks simple, Chuchelov said that the computers don't have it as a top recommendation.

Caruana must also know the ideas well -- he used the same opening from the opposite side against GM Dragan Solak at the 2014 Olympiad.>

Here are some <CG> Opening Explorer stats, it's a fairly recent idea, I think, without much play:

1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 e6 5.Nc3 a6 6.Nxc6 bxc6 7.Bd3 d5 8.O-O Nf6 9.Re1 Be7 10.e5 Nd7 11.Qg4 Kf8

12.Na4 3 ( 33% / 33% / 33% )

(12.Qe2 D Solak vs Caruana, 2014)

12...h4 2 ( 50% /50 % )

M Leon Hoyos vs Granda Zuniga, 2007 (13.Qf4 ... 0-1)

E Safarli vs K Shanava, 2014 (13.Qe2 ... 1-0)

You might do well to read the following kibitz: <csmath: 6. Nxc6 [Caruana is very well informed on theory here, he is going for a dangerous sideline in Taimanov.]>

Black's fifth move became far less popular for a time because of what you term 6.Nxc6?!

<....It seems most inadvisable unless Black's centre can be made to become a target instead of a weapon.....>

That is the intent, or to establish the wedge with e5, as took place in the game.

<In the position after 9...Be7 Black is behind in development but has central pawn superiority. White can hardly claim an advantage. Yet he plays an attacking move 10 e5? This attack is unsound then and can be forecast to fail.>

Some substantiation--concrete analysis rather than your trademark abstract reasoning--would be most welcome.>

Of course Mr. Naiditsch couldn't have known this back then.

I've always thought that Cold War hardened many players. My point is that, today there is no government official telling you that it is in your best interests to win the games you play.

Carlsen on the other hand reached his peak rating of 2882 in May-2014, dropped 20 points to 2862 in Dec-2014 and has reached 2876 in May-2015, just 8 points below his peak rating. So Carlsen has been more consistent than Caruana, with one good performance after another. I think that Caruana needs to show a similar consistency before he can be considered a serious threat to Carlsen.

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Rybka 4.1 x64: