Hans Niemann, the 19-year-old who has confessed to cheating in online games but denies any illegalities over the board, faces a crucial credibility test at St Louis on his US Championship debut.
The organisers have beefed up security, with spectators barred, a new metal detector to frisk players and a 30-minute delay before the games are displayed to online viewers. Live online coverage now starts at 7.30pm.