Round 6 of Reggio Emilia turned out as well as possible for Hikaru Nakamura. Nakamura entered the round in first, and he won his game while his closest competitors both lost theirs. With four rounds to go it's far too soon to hand him the tournament, but he's in great shape with a four point lead (on 3-1-0 scoring) over the second-placed Alexander Morozevich and a six point margin over Vassily Ivanchuk and the suddenly hot Anish Giri. (The latter beat the former.) Let's recap the games.
First, of course, there was Nakamura's game, a kind of model win on the white side of a Classical French against Nikita Vitiugov. Nakamura played very well, but Vitiugov, who is making his super-tournament debut, is clearly over his head. (In time I expect he'll get used to this kind of company, but for now he's the daily special on the menu - every day.) Nakamura is not only in great shape in the tournament, but he's also up to #5 in the world on the live list, but it will still take a while before he catches the Big Four. (Though maybe not that long a while if he keeps up this pace and repeats in Wijk aan Zee.)
Giri isn't yet an old hand in super-events, but he seems to have found his sea legs. He has played aggressively all tournament, and in the last two rounds it has paid off. In round 5 he beat Fabiano Caruana, and in this round he beat Ivanchuk with surprising ease. Ivanchuk played a Bogo-Indian line that has generally allowed Black to escape with a draw, but this time around he didn't even come close. Black's lousy pawn structure and feeble bishop vs. good knight made him suffer and eventually lose. Ivanchuk did force Giri to make some nice calculations in the pawn ending, but the youngster was up to the task and brought home the full point.
Finally, Morozevich had White against Caruana and thus - on paper - a fine opportunity to keep pace with Nakamura. Paper didn't help though, and Caruana was better most of the way, cashing in around the end of the first time control.
Standings After Round 6 (of 10, based on 3-1-0 scoring):
1. Nakamura 14
2. Morozevich 10
3-4. Ivanchuk, Giri 8
5. Caruana 7
6. Vitiugov 2
The day's rounds are here; I've annotated Nakamura's and Giri's wins.