Handbook ::  C. General Rules and Recommendations for Tournaments

C.04.5 FIDE-approved Accelerated Systems

In Swiss tournaments with a wide range of (mostly reliable) playing strengths, the results of the first round(s) are usually quite predictable. In the first round, only a few percent of the games have a result other than "win to the stronger part". The same may happen again in round two. It can be shown that, in title tournaments, this can prevent players from achieving norms.
An accelerated pairing is a variation of Swiss pairings in which the first rounds are modified in such a way as to overcome the aforementioned weaknesses of the Swiss system, without compromising the reliability of the final rankings.
It is not appropriate to design an entirely new pairing system for acceleration, but rather design a system that works together with existing FIDE-defined pairing systems. This result is normally achieved by rearranging score brackets in some way that is not only dependent on the points that the players have scored. For instance, one of the possible methods is to add so-called "virtual points" to the score of some higher rated players (who are supposedly stronger) and henceforth build the score brackets based on the total score (real score + virtual points).
The following chapters will describe the methods that were statistically proven to accomplish the aforementioned goals. The Baku Acceleration Method is presented first, because it was the first that, through statistical analysis, was proven to be good and stable (and is also easy to explain).
Other accelerated methods may be added, as long as they can be proven, through statistical analysis, to get better results than already described methods or, if their effectiveness is comparable, to be simpler.
Unless explicitly specified otherwise, each described acceleration method is applicable to any Swiss Pairing System.

C.04.5.1 Baku Acceleration




In its current presentation, the Baku Acceleration Method is applicable for tournaments that last nine rounds or more, and in which the standard scoring point system (one point for a win, half point for a draw) is used.


Initial Groups Division


Before the first round, the list of players to be paired (properly sorted) shall be split in two groups, GA and GB.
The first group (GA) shall contain the first half of the players, rounded up to the nearest even number. The second group (GB) shall contain all the remaining players.

  Note: for instance, if there are 161 players in the tournament, the nearest even number that comprises the first half of the players (i.e. 80.5) is 82. The formula 2 * Q (2 times Q), where Q is the number of players divided by 4 and rounded upwards, may be helpful in computing such number - that, besides being the number of GA-players, is also the pairing number of the last GA-player.


Late entries


If there are entries after the first round, those players shall be accommodated in the pairing list according to C.04.2.B/C (Initial Order/Late Entries).
The last GA-player shall be the same as in the previous round.

  Note 1: In such circumstances, the pairing number of the last GA-player may be different by the one set accordingly to Rule 2.
  Note 2: After the first round, GA may contain an odd number of players.


Virtual points


Before pairing the first three rounds, all the players in GA are assigned a number of points (called virtual points) equal to 1.
Such virtual points are reduced to 0.5 before pairing the fourth and the fifth round.

  Note: Consequently, no virtual points are given to players in GB or to any player after the fifth round has been played.


Pairing score


The pairing score of a player (i.e. the value used to define the scoregroups and internally sort them) is given by the sum of his standings points and the virtual points assigned to him.

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