The 2nd Sinquefield Cup still has six rounds remaining, but with only Maxime Vachier-Lagrave even within two points of Fabiano Caruana the prognosis for the rest of the field is getting grim.
Here's the quick summary of today's action:
Caruana defeated Levon Aronian, showing that the position after his/his coach's novelty 15.Na2 had its drop of poison. Aronian's view was that he needed to play ...Nc3 (I think on move 20), and while Caruana didn't directly address that he stated that once he played 22.Qh5 Black was in trouble; his assessment appears to be correct. The next exciting moment came a bit later when Caruana sacrificed a piece with 29.Na5 Nxa5 30.Nxe5. Various commentators expressed their surprise and at least mild disapproval, but Caruana's judgment was not only confirmed by the computer and the course of the game, but by the players themselves. The alternative, 29.Nh2, would be met by ...Rf4 once White played Ng4, and the exchange sacrifice would give Black comparatively good chances. So it's another huge win for the American-Italian*, now 4-0 and showing both fantastic preparation and great play after the prep as well.
The other two games were drawn, but after very different courses. Vachier-Lagrave vs. Hikaru Nakamura was an Archangelsk that was consistently interesting until it suddenly fizzled out to a draw, while Magnus Carlsen's draw with Veselin Topalov was rather strange. Carlsen obtained the sort of position where one would expect him to successfully grind against Topalov, but soon it was clear that Carlsen had overpressed. Topalov's big chance came on move 45. If he had found 45...Rc5 - a move that's well within his ability to spot and requires basically no further calculation - he probably would have won. Unfortunately for him (and for the rest of the field if Carlsen manages to play like his usual self) he missed the opportunity and the game was soon drawn.
Tomorrow's round finishes the first cycle, and Nakamura will have White against Caruana. Nakamura noted that he has a very good score against Caruana (though Caruana seemed less impressed about it), so he's feeling confident and will be loaded for bear. Will it matter? We'll see!
Here are the full pairings: Nakamura - Caruana, Aronian - Carlsen, Topalov - Vachier-Lagrave
One final note, for now: Carlsen (like everyone else) does have bad results and poor stretches every now and then, but I suspect that his battle with FIDE over the world championship match contract is taking something out of him.
* Please, Mr. Sinquefield, can't you bribe encourage Caruana to come back and represent the United States??
Update: Here are the games, with my brief(ish) notes.
Update II: As is clear from my notes, and as mentioned in the comments, my discussion of 45...Rc5 in the Carlsen - Topalov game was mistaken. It would have put some pressure on Carlsen, but there is a way for him to escape with a draw, and despite his apparent concern about it after the game I think it's pretty likely that he'd have found it.