Chess: Find the move that defeated a world champion

Last week’s $150,000 US Championship, played online and organised by America’s chess centre at St Louis, ended with its winner, Wesley So, harking back to Bobby Fischer’s brilliant performances in the 1960s. However, So’s achievement was slightly diminished by an artificial final round game that the legend would never have allowed.

The 27-year-old ex-Filipino world No9 won the $40,000 first prize with an unbeaten 9/11, a points total  only Fischer has equalled or surpassed, notably in his 11/11 sweep of 1963-64.

Half a point behind So was the rising star of US chess Jeffery Xiong, who turned 20 on October 30.

At the start of the final round So led Xiong by a one-point margin, though seemingly with the harder pairing against the out of form defending champion Hikaru Nakamura. 

So v Nakamura repeated their final round draw in the 2018 championship for 25 moves, then halved out  The game, played at blitz speed, was over in under a quarter of an hour. It was the antithesis of Fischer, who in the 1963-64 final round patiently ground down Anthony Saidy from a level endgame to ensure his 100 per cent total.

Puzzle 2392

Santosh Vidit v Vlad Kramnik, Leiden 2019. White (to play) is a pawn down with his f7 rook attacked. What was his winning move which defeated Russia's ex-world champion?

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