The use of a form of the verb “to whelm” (sans the prefix “over—“) is elegant. The only other such usage that immediately comes to mind is in the following brilliant passage from the concluding lines of Chapter 52 of <Moby Dick>:

<“But in pursuit of those far mysteries we dream of, or in tormented chase of that demon phantom that, some time or other, swims before all human hearts; while chasing such over this round globe, they either lead us on in barren mazes or midway leave us whelmed.”>

This would have been a good excuse 50 years ago not today. Caruana simply has not done his homework and he is going to lose quickly as a result.> <from page 2>

That comment (‘simply has not done his homework’) seems unfair. I am sure Caruana has done a lot of home preparation, but no one can be prepared for every variation that might occur. Lapses of memory can also afflict even super-GMs from time to time during the stress of a high-tension game.

The white attack setup (first 9 moves) is played by Mamedyarov and Svidler just to mention two of the Grunfeld/anti-Grunfend specialists.

The move 10. h4 was first played by Grischuk against Mamedyarov in 2010 as noted previously and the game was drawn). By the way h4 is a standard attack idea in many Grunfeld lines.

This year Evgeny Postny (strong Israeli GM) has played this twice and won both times against lesser opponents. They both responded correctly (as opposed to Caruana) with

14. hxg6 fxg6
15. g4 e5

and this is now known theoretical line.
Obviously Caruana did not know that and blundered with

14. ...hxg6?

after which the game was simply lost.
The move enables threat of 15. Bxd4 Bxd4, 16. Qh6 or as in the game, in both cases lost.

There is more to the theory. For example returning pawn with

14. hxg6 fxg6
15. g4 e5
16. Qh2 h6?!

leads to a strong attack as white is able to double rooks on h-file (Rd2-Rh2) and close black position with g5. This leads to a very difficult position for black.

However

16. ...Bf6

seems to equalize the game. This should all be known to Caruana. I am not entirely convinced that the whole variation is safe for black but I would like to see that played on the top level.

It depends on how much of a boor you are when doing it. In a chess forum, it's fine. :-)

What's this? Tribe talk at cg.com? Well let's play What If ...

While I agree he misanalysed the position at the board, missing 15 Bxd4, his preparation was the cause, thinking that 14...fxg6 was very dangerous.>

That's surprising as 14...hxg6?? is busted immediately by 15. Bxd6!

Indeed, 14...fxg6 is the only move that doesn't lose immediately to White's next reply.

For one thing, after 14...fxg6 the reply 15. Bxd4? is no longer good for White since 15...d4 16. Qh6? e5! 17. Nge2 Qg7 18. Qg5 Be6 leaves Black a solid pawn up and in fine shape.

Of course I suppose 14...fxg6 would have played into "theory" and Nakumara's prepared 15. g4, which I admit looks unclear and hard to assess.