A leading contender to become the World Blitz Chess Champion had to withdraw from the competition on Thursday after testing positive for COVID-19.

The International Chess Federation (FIDE) said "a couple of players" had tested positive and could no longer take part in the major championship held in Warsaw in Poland.

Among them was Hikaru Nakamura, one of the world's top blitz chess players and also a popular streaming star on Twitch. He had felt ill earlier in the competition but tested negative, only to then log a positive PCR test he had taken so that he would be able to fly out of Warsaw.

"I cannot finish the tournament and now am worried for all my opponents," Nakamura wrote on Twitter.

Despite FIDE's assurances that other players had been informed of the outbreak, German player Maximillian Berchtenbreiter wrote on Twitter that he only learned about via a friend who alerted him to Nakamura's announcement.

Players could only use public testing facilities

Several players had complained of having to wait for hours to get tested at city center facilities open to the general public in Warsaw, rather than having the capacity for testing at or near the site, including Nakamura shortly before his positive result. 

Indian Chess Grandmaster, Vidit Gujrathi wrote on Twitter he had to abandon the queue after two hours and return so that he would not forfeit his first game of the day.

FIDE said it was "terribly sorry" for the "unfortunate circumstances" and would provide logistical support to the affected players.

Warsaw stepped in at last minute as host

The World Blitz Chess Championship started on Wednesday, a day after the longer time-format World Rapid Chess Championship finished in the same venue.

In total, around 300 of the best male and female players in the world had descended on Warsaw for either the rapid or the blitz championships, or for both. 

In the World Blitz Chess Championship, each player has 3 minutes on the clock to finish a game, plus an extra 2 seconds per move.

FIDE and the organizers in Warsaw had to race against the clock to prepare for the competition. Until December 9, the tournament was scheduled to be held in Kazakhstan. But as the omicron variant first began to spread organizers in Nur Sultan canceled the event, citing concerns over safety and travel restrictions.

The next day, Warsaw, which hosted the last Rapid and Blitz Championships in 2019, announced that it would step in as the 2021 venue. The 2020 event was canceled outright, also because of COVID.

'MVL' wins men's blitz title after three tie-breakers

French star Maxime Vachier-Lagrave ultimately walked away with the men's blitz title on Thursday evening, after three rounds of tie-breakers with Polish player Jan-Kryzsztof Duda. 

Alireza Firouzja, seen by many as the natural heir to world number 1 and outgoing blitz champion Magnus Carlsen, actually finished the regular games with the same score as "MVL" and Duda.

However, he lost out by the complex set of rules used to pick the leading two players if more than two have the same number of points. It had been a similar story in the men's rapid championship, too, where four players were tied on points but only two advanced to the tie-breaker.

In the women's competition, 17-year-old Bibisara Assaubayeva from Kazakhstan won the tournament with no need for tie-breakers, mathematically assuring overall victory with a round of games to spare. Russian player Kateryna Lagno was the heavy favorite going into the competition having claimed the title in 2019 and 2018.

Edited by: Mark Hallam