The largest chess tournament: the records and how such events are run

The Guinness record in the category «largest board game tournament» belongs to chess: 43,157 entrants. The event was run by the sports commission of the city of Cebu in the Philippines on 22 January 2012.

This really was a tournament: people played games against each other, not against a single master. The scale is roughly what it would look like if an entire small town took part - children and pensioners included.

The entry in the register - Guinness World Records.

The second record, the one most often quoted in answer to the same question, works differently. On 24 December 2010, on the sports fields of Gujarat University in Ahmedabad, 20,480 games were played simultaneously.

But that was not a tournament, it was a mass simultaneous display: 1,024 masters played against 20,017 opponents. Every participant played one game against a strong player, not a series of games against equals. The previous mark was 13,446 people in Mexico City in 2006.

The difference matters, and it is exactly why the figures in second-hand accounts do not add up: in a tournament a person plays several rounds and appears in a common table; in a simul, one game against a master. How a simul works - the simultaneous exhibition.

The biggest record by number of games was not gathered in one place. On 20 July 2024, FIDE's centenary, 7,284,970 games were played worldwide in twenty-four hours. Results were submitted by 109 national federations.

A curious detail: the countries that submitted the most games were not the ones that sound like chess countries. Near the top of the list were Sri Lanka, India and Kazakhstan.

The details - on the FIDE site.

The most instructive story about how records are counted. The Iranian grandmaster Ehsan Ghaem Maghami gave a simul on 604 boards in Tehran on 8-9 February 2011: twenty-five hours straight, 580 wins, 16 draws, 8 losses.

And the Guinness register, under «most simultaneous games by one player», says 135. The reason is the category rules: only opponents with a confirmed rating of 1200 or above count. The other 469 people did not meet the rating requirement and were not included.

Hence a practical conclusion for any organizer: a record is not «a lot of people turned up» but a set of rules met. If you are attempting something record-breaking, the conditions of the category get read before the event, not after it.

Mass events are not «the same but bigger». A few things break before the rest.

• The format. A round-robin with a hundred players is physically impossible: everybody would have to play 99 games. Mass events are played as Swiss tournaments - which format to pick.
• The number of rounds. It does not grow in proportion to the number of people but roughly as the binary logarithm: doubling the field adds a single round - the table by number of players.
• The pairing. With twenty players it can still be done by hand; with two hundred it cannot. You need software - a survey of the programs.
• Registration and data. Collecting entries on paper at scale becomes the main source of errors in the table - registering players.
• Venue and equipment. You need exactly half as many sets and clocks as there are players, and more space than the number of tables suggests - the venue and boards and sets.

And the thing the record events make plainest: almost all of them rest on a team of volunteers and a script written in advance. On that - volunteers and the tournament team and how to organize a tournament.