Much like the plot out of Agatha Christie’s acclaimed 1939 tense thriller that sees just about everyone being systematically killed off, the “murderous” schedule of the $1.6m FIDE World Cup in Tbilisi, Georgia, has seen the original starting field of 128-players now whittled down to the final four – and with it, now the big semifinal clashes that will see Levon Aronian (Armenia) vs Maxime Vachier-Lagrave (France) and Wesley So (USA) vs Ding Liren (China).

But there’s a calm before the storm because, for the first time in 16 days of intense, often brutal battle, there’s no play today in the competition, as the final four contestants have a little respite before readying themselves for Tuesday’s semifinals, as the tournament heads towards its climax of the four-game final that starts 23 Sept., where up for grabs is two spots for next year’s Berlin Candidates tournament, as well as the lion’s share of the prize money on offer.

For Aronian, who easily dispatched veteran Vassily Ivanchuk in the previous round, this could be his last chance to make it to the Candidates next March. The back-in-form Armenian is too far behind in both the year-long Grand Prix series of tournaments and ratings-race to make it to the Candidates – so getting to the World Cup final could well be his only route to Berlin.

Standing in his way is MVL, who edged Peter Svidler out in the quarterfinals. The Frenchman is another player that’s very much in-form this year, and that makes the match-up between these two the standout pairing of the semis. Like Aronian, MVL has won a lot of tournaments this year ahead of World champion Magnus Carlsen – but the Frenchman could also have another path to Berlin, by virtue of winning the final Las Palmas Grand Prix in mid-November.

In the other semifinal pairing, neither So nor Ding Liren – who respectively easily beat Vladimir Fedoseev and Richard Rapport in the previous round – have lost a game yet in the competition. The favorite is reigning US champion So – who holds a slim lead over Vladimir Kramnik in the ratings’ race second spot behind Fabiano Caruana – who now looks to be back in-form with some very smooth performances in Tbilisi.

GM Wesley So – GM Vladimir Fedoseev
FIDE World Cup, (5.2)
Petroff’s Defence
1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nf3 Nxe4 5.d4 d5 6.Bd3 Be7 7.0-0 Nc6 8.Nbd2 Bf5 9.Re1 Nxd2 10.Qxd2 Bxd3 11.Qxd3 Wesley So adopts a simple line against the Petroff; the idea being to bring pressure down the e-file by doubling rooks. 11…0-0 12.c3 Qd7 13.Bf4 a6 14.Re2 Rae8 15.Rae1 Bd8 16.Nd2 Rxe2 17.Qxe2 White’s advantage is in his domination of the e-file – but can Wesley extract enough of an advantage from it to squeeze a win? 17…a5 18.Nb3 b6 Prophylaxis, plain and simple – Fedoseev wants to prevent Nb3-c1-c5. There’s not much in the position here, but Wesley extracts as much as he can out of the position was some nice touches. 19.Nc1 f6 20.a4 Wesley rightly assesses that it is too dangerous for Fedoseev to try to capture the a4-pawn, as Black will have trouble defending the many many weaknesses left in its wake. 20…Ne7 21.Nd3 g5 Black would like to take the a4-pawn without having to loosen his position with …g5 – but if 21…Qxa4 22.Bxc7 Bxc7 23.Qxe7 Rf7 24.Qe2! Qd7 25.Qh5! White is going to end up with a rather annoying edge with the target on d5 – and in the long-term, his plan will be f4-f5 followed by Re6 and Qe2 dominating the e-file. 22.Bc1 Ng6 Again, snatching the pawn is fraught with dangers: 22…Qxa4 23.h4! and White begins the process of exploiting Black’s loose position. Now, if 23…Ng6 (Not 23…gxh4 24.Bh6! Rf7 25.Qe6 and there’s no way to stop the winning plan of Nf4-h5.) 24.Qe6+ Rf7 25.hxg5 fxg5 26.Qxd5 leaves White with a big advantage that’s going to be difficult to defend against. 23.b3 Be7 24.h4 gxh4 25.Nf4 Rf7 The young Russian is in a fix, as ultimately his position has too many weaknesses – and although marginally a little better, the alternative was no better: 25…Nxf4 26.Qxe7 Qg4 27.Bxf4 Qxf4 28.Re3! and it’s hard to see a good continuation for Black here, other than 28…Qd6 29.Qxd6 cxd6 30.Re6 leaves Black – lumbered with all his pawn weaknesses – having to defend a really bad rook and pawn ending. 26.Qe6 Qxe6 27.Rxe6 Nxf4 28.Bxf4 Bd8 Fedoseev may well be a pawn up here, but Black has so many pawn weaknesses that So will easily recoup his deficit and then some – but what the young Russian is trying to do, is hunker down to find a way to defend the ensuing difficult endgame. 29.b4! Kg7 Black can’t capture as 29…axb4 30.cxb4 will gift White with a powerful outside passed pawn. 30.bxa5 bxa5 31.Ra6 c6 Again, the outside passed pawn will be a winner, leaving Fedoseev with the only alternative left to him. 32.Rxc6 Kg6 The pawns are equal, and Fedoseev has at least activated his king – but what will ultimately decide the game now is Black’s chronic weaknesses with five isolated pawns and five pawn islands. 33.Rc5 Rd7 34.f3 So just wants to stop his opponent’s king infiltrating into his position with …Ke4-d3 etc. 34…Kf5 35.Bd2 Ke6 36.Rc6+ Kf5 37.Be1 Kg5 38.Rc5 Something has to give, as So is now threatening 39.c4 hitting d5, a5 and also h4. 38…f5 39.Kh2! The pawn weakness on h4 affords So the time to better relocate his bishop. 39…Kh5 40.Bf2 Rd6 41.Be3 Bb6 42.Rb5 Bd8 43.Bf4 Rd7 44.Be5 Kg5 45.Rc5 f4 Instead, 45…Kh5 would have held out a little longer – but defending this sort of position is a nightmare for Black. 46.Rc6 Kf5 47.Ra6 Kg5 48.Kh3 Kf5 49.Rc6 Kg5 50.Re6 Be7 If 50…Kf5 51.Re8 threatens the simple win of the f-pawn with Rf8+, forcing Black into 51…Bg5 52.Rf8+ Ke6 53.Kg4 and White’s king, rook and bishop will mop-up Black’s weak pawns on f4 and h4. 51.Rc6 Bd8 52.Bd6 Kf5 53.Kh2 Black has no play here whatsoever and has to wait for his fate to be decided for him, as So very carefully builds his ideal position for the inevitable endgame win. 53…Rg7 54.Be5 Rd7 55.Rd6! The engines may well prefer keeping the rooks on the board, but So is quick to see the human frailty in the bishop ending, as there’s no way for Black to defend his multiple pawn weaknesses on a5, f4 and h4. 55…Rxd6 56.Bxd6 Kg5 57.Kg1 The king is heading for d3 to help support a c4 break. 57…Kf5 58.Kf2 Kg5 59.Kf1 Kf5 60.Ba3 Ke6 61.Ke2 Kf5 62.Bc1 Kg5 It’s a hopeless position for Black to defend. If 62…Bg5 63.Kd3! threatens Bd2 and c4 that will easily win. At least with 62…Kg5, Black has the mini-threat hanging in the air of a later …h3 that could well save the day. 63.Kf1 Preventing any …h3 chances. 63…Bc7 64.Bd2 Bd8 65.Be1 Kf5 66.Ke2 With the Be1 now stopping …h4 followed by Kg5-h4, So now gets his king back to the queenside. 66…Ke6 67.Kd3 Kd7 68.c4! (see diagram) In the end, Fedoseev is going to find himself in Zugzwang, as So can triangulate his bishop into a position where Black can’t defend his pawn weaknesses on a5, f4 & h4. 68…Kc6 69.Bc3 Bb6 70.Bb2 Bd8 71.Bc1 Bc7 72.Bd2 Now …Bd8 is prevented, as it will lose the pawn on f4 – and Black is soon going to run out of useful moves to make that doesn’t lose. 72…h5 73.Bc3 Bb6 74.Bb2 Bc7 75.Ba3! Now the threat hanging in the air is Be7 winning the h4 pawn. 75…Bd8 76.Bf8 Bg5 77.Bg7 Kd6 78.Be5+ Kc6 79.Kc3 Bh6 80.Bf6 Bf8 81.Kd3 h3 82.gxh3 Bd6 83.Be5 1-0 A wonderfully smooth performance from US champion Wesley So!