I was just playing through some games from the US Championship (Kamsky currently leads with 5/6; Onischuk and Ramirez are half a point back with 3 to play), and there were 3 positions from today that looked quite interesting.
(1) Robson – Shulman
This came from an Exchange French Winawer, which unlike the normal Exchange Variation, actually has some venom. From what I remember of the opening theory, if Black just tries to play some normal moves, White might well get a tiny pull. But Shulman played it quite strangely, neglecting his king’s safety to bring his Queen out to f6 and then exchange light-squared bishops. But what should White do here?
Robson played the very strong, and very unnatural looking (at least to me), 9.cxd3!. It’s a very concrete move, taking full advantage of Black’s king’s position. It’s hard to believe at first, but Black is already lost!
White has two ideas here – one is the obvious Re1+ with Bg5 likely to follow, while the other is Qb3 and just a demolition of the queenside after taking on b7. Black has no good way to deal with the threats. Taking on c3 eliminates the Qb3 threat, but then after 10.bxc3 Ne7 11.Re1, Black faces additional problems with Ba3 on deck.
Shulman chose to give up castling by playing 9…Na6 10.Re1+ Kf8, but after 11.Ne5 Qd8 12.Bg5, his position was no fun. Robson did give his advantage a few times, but he managed to collect the full point in the end.
(2) Shabalov – Hess
(FEN: 5rk1/1b1nqpp1/r3pn1p/p1b5/R3PB2/3N1NP1/1PQ2PBP/3R2K1)
Black’s opening play made no sense to me, and White has a clear plus here. Shabalov took it somewhat slow actually with 18.Nfe5 Rc8 19.Nc4, when his better pieces kept an advantage, but it was only later that it reached winning proportions.
Instead, he could have decided things almost on the spot with 18.e5! Nd5 (normally this would make no sense, as Black just got the nice d5-square), but 19.Bxh6! is the point. The clearance of the 4th rank for the Rook on a4 is a nice motif and Black can’t take back on h6. If 19…gxh6 20.Rg4+ Kh8 21.Nxc5 Nxc5 22.Qc1 Kh7 23.Rh4 and there’s no choice but to throw the queen away (and even then, the attack doesn’t stop). (Also, no, I didn’t see this e5/Bxh6 idea on my own right away, I saw some computer analysis)
(3) Shankland – Troff
(FEN: r3n1kb/pq1rnp1p/1p1pp1p1/6B1/2P1P2Q/1PNR1P2/P3N1PP/5RK1)
Here’s another rook lift, but this one is somewhat more intuitive I think. Black’s pieces make a strange impression, all on his first two ranks, and the kingside looks awfully deserted. So instead of the formulaic 20.Rfd1, White should have played 20.f4!, threatening to swing the rook over to h3.
Black can’t really do a whole lot – …f6 just further weakens his position and doesn’t even trap the bishop. As soon as he plays …h5, White can consider moves like f4-f5 when “winning” a pawn likely entails getting checkmated, while the alternative is to have weak pawns on d6, e6, and g6. Sam would have had great chances to win the game in that case I think. Instead, Rfd1 lost some time, but more importantly, the force behind f4-f5 in those lines disappears and White doesn’t have a great followup anymore.
There and Back Again 
Robson is kind of on fire after a bad start (for him). Who would’ve guessed that Shulman would’ve been on -1 after 6 rounds. I guess his rating is down a bit from where it used to be. I can’t believe you didn’t mention Holt’s Bc5. Maybe it’s more obvious that “something is going on here” after that move, but the tactics were concrete.
A bit late, but yeah – Robson has worked his way back into the tournament. I imagine he’ll be white vs Kamsky in the last round tomorrow.
The sequence from Christiansen – Holt was nice, but I thought there was going to be something going on. At first, I thought …Rg4+ would win the queen, but then I saw the clear mating pattern. So then …Bc5 suggested itself. So while I literally did a double take while quickly playing through this game (as I wonder why not Rg4+), it didn’t take long to see the point behind Bc5. Still, a nice game, and a great tournament for Holt. Honestly, it’s kind of amazing to me that him and/or Ramirez could potentially tie for first place if they win tomorrow and Kamsky draws.