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Here are the pairings for the 2017 FIDE World Cup. The above pairings are for 128-player knockouts. I can't get the way the pairings were generated. I want to be able to generate pairings using the same criteria for knockouts with different numbers of players.

Are there any FIDE published rules for single-elimination tournaments, such as the World Cup? If not, what are the criteria they use for such pairings?

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The participants were seeded by their FIDE rating: the highest rated player (Magnus Carlsen, 2822) got #1; Wesley So, rated 2810, got #2, all the way down to Oluwafemi Balogun (2255), seed #128.

In the first round, the player with number x plays against the opponent with number 129 - x. So 1 vs. 128, 2 vs. 127, and so on.

In the second round, assuming the stronger player (with the lower number) advances, the player with number x plays against the opponent with number 65 - x. So 1 vs. 64 (this actually happened) and 9 vs. 56 (but this became 9 vs. 73 since 73 beat 56).

The 'target sum' for the third round is 33, for the fourth round 17, and so on until the final where #1 is supposed to play against #2.

This all is a standard seeding mechanism used in many sports (sometimes with slight variations); actually, in most cases, only the top n% (25% is common) of the players is seeded and the rest are paired randomly. This tournament was 'completely' seeded, which is relatively rare.

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  • Thanks. This explains the pairings for the first round. But which bracket does each player get into?
    – Wais Kamal
    May 24, 2019 at 13:58
  • @WaisKamal That's determined by the seeding. If you have 128 players and the brackets cover the first 4 rounds, then in round 5 you're aiming for seed 1 to play seed 8. So, if seed 1 is in bracket 1, seed 8 needs to be in bracket 2.
    – D M
    May 24, 2019 at 22:46
  • One also has to be clever in assigning colors. If you give all the top half the same color in round 1 you will soon run into problems. The usual is to reverse color so the initial even numbers get black and the initial odds get white. Some directors may flip a coin to see which color the top player starts with.
    – yobamamama
    Dec 28, 2019 at 3:43

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