The favourites Magnus Carlsen and Levon Aronian are dominating the €510,000 world title candidates at the London IET in Savoy Place, which reaches its halfway mark this weekend.
They share the lead with three wins and three draws each, 4.5/6, while none of the other six grandmasters has bettered 50%. The Norwegian and the Armenian are likely to be still fighting it out when the 14-round event reaches its climax on 1 April.
Rounds 7 and 8 this weekend (2pm GMT start) include Carlsen v Aronian on Sunday which looks the key game for deciding first prize and the right to challenge India's Vishy Anand for his world title. You can follow it free and live at www.chessbomb.com or on the official site at www.worldchess.com (click on game analysis).
Carlsen's win from Boris Gelfand was in the 22-year-old's trademark style of a minimal edge from the opening which he then squeezed into a serious plus around the time control, before concluding with a majestic endgame featured in this week's puzzle.
Aronian has a more complex approach and his three wins have all been rich in tactics. The 30-year-old is a momentum player who notched up victory sequences at Wijk 2011 before leading Armenia to three Olympiad gold medals.
The two over-40s, Vasily Ivanchuk and Gelfand, have both mishandled their time and Ivanchuk even failed to make the move 40 control in two successive rounds. Before the start Carlsen said he would aim for around a 9/14 total, in effect challenging Aronian to take risks to better that. But the early identification of Ivanchuk and Gelfand as the event's vulnerable bunnies has raised the bar for the winning score.
There have been some notable openings. Peter Svidler v Vlad Kramnik began 1 d4 d5 2 c4 e6 3 Nc3 Nf6 4 cxd5 and now 4...Nxd5 which has long been reckoned inferior to recapturing with the pawn 5 e4 Nxc3 6 bxc3 c5 7 a3 (stopping Bb4+) cxd4 8 cxd4 e5! and Kramnik equalised and drew easily.
Gelfand v Carlsen started 1 d4 Nf6 2 c4 e6 3 Nf3 d5 4 Nc3 Nbd7 5 Bg5 c6 6 e3 Qa5. This is the Cambridge Springs, rare at top level for the best part of a century but suiting Carlsen's chances of squeezing out wins as Black.
Carlsen's win below was strategy encompassing the entire board, destroying Black's Q-side while fending off the counter to his own king. Black went wrong by 17...f5? (Qg6).
M Carlsen v A Grischuk
1 e4 e5 2 Nf3 Nc6 3 Bb5 Nf6 4 d3 Bc5 5 c3 O-O 6 O-O d6 7 h3 a6 8 Bxc6 bxc6 9 Re1 Re8 10 Nbd2 d5 11 exd5 Qxd5 12 Nb3 Bf8 13 c4 Qd6 14 Be3 Nd7 15 d4 e4 16 Nfd2 a5 17 a4 f5? 18 c5 Qg6? 19 Nc4 Nf6 20 Bf4 Nd5 21 Qd2 Be6 22 Nbxa5 Reb8 23 Ne5 Qf6 24 Bh2! Rxa5 25 Qxa5 Rxb2 26 Rab1 Ra2 27 Qa6 e3 28 fxe3 Qg5 29 Re2 Nxe3 30 Nf3 Qg6 31 Rxa2 Bxa2 32 Rb2 Bc4 33 Qa5 Bd5 34 Qe1 f4 35 Bxf4 Nc2 36 Qf2 Bxf3 37 Rxc2 1-0
3298 1...Kg6! is zugzwang where White must make a losing move. Any pawn advance, Black captures it. If 2 Bb4 b2 3 Kc2 a2 wins. If 2 Kxc4 b2. The game ended 2 Bd4 b2 3 Kc2 Nd2! and White resigned. After 4 Bxb2 (4 Kxd2 b1Q) axb2 5 Kxa2 Nf3 when Black eats the white pawns and queens his f2 pawn.