The Grand Tour circuit has moved from Paris to Leuven, near Brussels, this week but the continuing story remains the world champion Magnus Carlsen’s inconsistent form. The Norwegian, 26, won the one-hour rapid section in Paris, then lost three games in a row at five-minute blitz. A late rally in the 18-round event enabled him to tie in the overall standings with Maxime Vachier-Lagrave and he won the play-off when the Frenchman failed to spot a resource shown in this week’s puzzle diagram.

Carlsen, along with MV-L and America’s world No3 Wesley So, were the only grandmasters scheduled to play at both Paris and Leuven, where their rivals are headed by the former world champions Vlad Kramnik and Vishy Anand and by Levon Aronian, the recent winner at Stavanger. Expectations that Carlsen would hit vintage form in Belgium were unfounded; on the first day of rapids So caught the No1’s king in a queen and rook crossfire and forced resignation. It was an important point for the US champion, who covets Carlsen’s crown but has hitherto found him a difficult opponent.

The final Leuven rapid scores were: So 14 (out of 18, with two points for a win), Vachier-Lagrave 12, Carlsen 11, Anish Giri (Netherlands) 10.

The 18 rounds of blitz take place this weekend and can be watched free and live online with GM and computer commentaries, starting 1pm BST Saturday and 11am Sunday. The official site has the best viewing, with videos of the actual games plus lucid commentaries by Yasser Seirawan and by England’s top woman player, Jovanka Houska.

Carlsen’s uneven results could be partly caused by a change in the format of the blitz games. The 2016 Grand Tour required five minutes per player per game, plus an increment of three seconds per move. For 2017 the increment was altered to just a three seconds delay before the clock restarted, meaning that time could not be banked by a fast opening and that the final moves had to be made almost instantaneously. This led to some awful blunders in the Paris blitz. Carlsen’s three-game losing sequence, the first of his entire career, included a one-move catastrophe changing an advantage into an instant defeat.

There was also a rule in Paris that if a player had less than 20 seconds remaining, knocked over some pieces, then pressed his clock before replacing them, he could be defaulted if the opponent complained. Reports suggested that there were several knock-overs and that Carlsen was the clumsiest player. Nobody complained, though, and for Leuven the rule has been modified so that on the first occasion the player only receives a warning.

The world team championships in Khanty-Mansiysk, Russian Siberia were dominated by China and the host nation. China won the men’s title ahead of Russia and Poland, Russia the women’s competition ahead of China and Georgia. Some teams were badly weakened, notably the United States whose top three elite GMs were all playing in Paris. England declined an invitation to replace a late withdrawal, since there was little enthusiasm among our leading GMs for a long journey at minimal notice.

China fielded their top four of Ding Liren, Yu Yangyi, 18-year-old Wei Yi, and Li Chao. It was their second victory in the world teams after 2015 and they also won the 2014 Olympiad. The squad’s average age is only 24, so they could dominate world team chess for most of the next decade. On paper they should have won comfortably in Khanty after outplaying Russia in the very first round, but thereafter they made heavy weather of it.

When Russia beat the US 4-0 in the final round they were ahead on game points while China v Poland stood 1.5-1.5, so that Li Chao needed to score so as to give China an extra match point and take the gold medals to Beijing. He was up for it, though, choosing an interesting opening plan which has been played several times in the Chinese League and analysed by their top quartet, who work as a cooperative.

The classical Slav Defence goes 5...Bf5, but Black instead switches to a Queen’s Gambit Accepted where a2-a4 is reckoned harmless. Then White kicks in with 9 Nxd4!? avoiding an isolated d4 pawn, with the point that if 9...Nxd4?! 10 exd4 Be7 11 d5! White establishes a powerful bisbop at d5. Li Chao’s 11 e4! improves on 11 Nf3 played by Sergey Karjakin in 2016, while 12 Qe3! and 15 Re1! both products of pre-game homework, confirm White’s edge. Black’s decisive error is 20...Nf8? when the active Nc5! keeps him in the fight. White’s 24 Nc3! and 25 Ne4! is strategically decisive, since Qf4/Bg5 will force an invasion of f6. In the actual game Black tried for counterplay, but was soon lost.

Li Chao v Mateusz Bartel

1 d4 d5 2 c4 c6 3 Nf3 Nf6 4 Nc3 dxc4 5 a4 e6 6 e3 c5 7 Bxc4 Nc6 8 O-O cxd4 9 Nxd4!? Bd7 10 e4!? Nxd4 11 Qxd4 Bc6 12 Qe3! Be7 13 e5 Nd7 14 Qg3 g6 15 Re1! O-O 16 Bh6 Re8 17 Rad1 Qc7 18 h4 Rad8 19 Rc1 Qb6 20 h5 Nf8? 21 b3 a6 22 Ne2 Bd5 23 Bxd5 Rxd5 24 Nc3! Rd7 25 Ne4! Qd8 26 Qf3 Rd3 27 Re3 Rd4 28 Qf4 g5 29 Qg3 Rd1+ 30 Re1 Rd3 31 f3 f6 32 exf6 Bxf6 33 Bxg5 Bxg5 34 Nxg5 Qd4+ 35 Kh2 Qg7 36 Rc7 Rd7 37 Rxd7 Nxd7 38 Rxe6 1-0

3501 If 1...a3! 2 Nh6 threatening 3 Ra8 mate looks deadly – but Black has the resource 2...Rf2+! 3 Kxf2 (3 Kg1 Rxf6) Bc5+ and Bxa7, winning.