Hans Niemann, the controversial US grandmaster whose game with Magnus Carlsen at the 2022 Sinquefield Cup led to cheating allegations , a $100m lawsuit, an out of court settlement, the Netflix documentary Untold: Chess Mates , and a forthcoming book, scored the most important success of his career last weekend. Niemann, competing as a wildcard, won the $50,000 first prize at the Warsaw Rapid & Blitz in Poland, ahead of the US champion and the world No 3, Fabiano Caruana, India’s reigning world champion, Gukesh Dommaraju, and the Candidates winner, Javokhir Sindarov. The event was part of the St Louis-backed Grand Chess Tour, which ends in August and includes the prestigious Sinquefield Cup. The 22-year-old world No 12 scored 22.5/36, finishing half a point ahead of Caruana, with Wesley So on 21 in third on an all-American podium. Niemann dominated the rapid section, where he was unbeaten, so was able to survive a run of three successive defeats in the blitz.…