DROLES DE ZEBRES championship organization

League structure

The championship is played in round robins of 10 players each. The players are divided into leagues. The top 10 players are in the first league and dispute the championship. The next 20 players are in the second league, which is split into 2 round robins, the next 40 are in the third league and so on.

The top 2 finishers in each round robin advance to the next higher league (if there is one) in the next tournament and the bottom 4 finishers in each round robin move down a league. New players start in the lowest league.

Round robin results

A victory is equal to 1 point and a defeat 0 point.

The players are ranked by the following criteria:
  1. Greater number of points obtained in all the games ;
  2. Greater number of points obtained by defeated opponents in all the games (Sonnenborn-Berger) ;
  3. Greater number of victories obtained in the games between the players concerned ;
  4. Greater particular points* difference obtained in all the games ;
  5. Greater particular points scored in all the games ;
  6. Lower Elo in the players’ Boîte à Jeux DROLES DE ZEBRES Elo ranking at the beginning of the championship.
* Particular point is the number of points scored by a player in a game.

Championship duration

In Boîte à Jeux, games have no time limit. Nevertheless, so that the championship is not blocked indefinitely by players who register but then abandon their games, the championship will have a maximum duration of 3 months. At that time any unfinished matches will be decided by the time taken to play and the number of particular points scored by each player. This duration of 3 months could be extended during summer or if the remaining games are near the end.

Withdrawal

Championship is a kind of competition that is intended especially for people playing regularly on Boîte à Jeux. Organizer reserves oneself a right to exclude from the current championship any competitor who blocks the championship's good working (in playing not very often to prevent finishing season on time) and/or distorts final results. Competitors must begin all their games from the beginning of the season and play all them at the same time.

Furthemore, a player who has not moved in a month will be withdrawn unless he notifies organizer and his opponents in advance in the Boîte à Jeux DROLES DE ZEBRES forum that his absence will not be too long and that he will be able to keep his games moving when he returns. Otherwise, a withdrawn player will be excluded from the current championship and all his results in the current championship will be cancelled. He will be able to register for a future championship but in the lowest league. Players cannot be withdrawn in July and August.

Unregistration

When a player unregisters from the championship, he must indicate before the beginning of the next season. Furthermore, if the player registers again, he will placed in the league where he was (or as near as possible), but only if there are vacancies due to unregistrations and/or withdrew.

Remaining in league due to vacancy

The withdrawal or unregistration of a player from the next championship may create a vacancy in his league. Such a vacancy is filled by moving one less player down to the next league. That leaves a vacancy in the next lower league, which is also filled by moving one less player down. The rules for determining which player to not move down are different for the unregistered player’s league and for lower leagues. The lowest league never has vacancies since the number of players in it is not fixed.

Unregistered player’s league

The basic rule is to fill a vacancy in the unregistered player’s league by keeping the highest finishing player who would have moved down from the unregistered player’s group. Do not fill a vacancy by keeping a player from another group except in the unlikely event of more players unregistering than would have moved down. The details differ depending on whether the unregistered player would have moved up, stayed in the league or moved down.

  1. Unregistered player would have moved up : Apply the basic rule to fill the vacancy. Also, two players must move up, so the third player in the group moves up instead of the unregistered player. The general rule is that the two highest registered players in the unregistered player’s group move up.
  2. Unregistered player would have stayed in the league : Apply the basic rule to fill the vacancy.
  3. Unregistered player would have moved down : In this case there is no vacancy in the unregistered player’s league. No player must be kept in the league due to the unregistration.

Lower leagues

When a vacancy occurs in a league due to an unregistration in a higher league, the player who is kept in the league to fill the vacancy could be in any group in the league. First apply the above rules to each group in the league to fill any vacancies due to unregistrations of players in the group. Then use the following criteria to fill vacancies in the league due to unregistrations in higher leagues.

  1. The total number of players remaining in each group must differ by no more than one.
  2. Vacancies filled must be allocated fairly among the groups.
  3. Last, fill a vacancy with the player with the highest result for the season among players who would move down.

Division into groups

The goal is to divide players in a league into groups based on their ranking from the previous championship in a way that maximizes mixing, i.e. the number of new opponents in each player’s group. The distribution of players who move up or move down is done according to their ranking and drawing of lots. For players who move up, an old group’s first player is put into the same new group as an old (different if possible) group’s second player. For players who move down, an old group's seventh is always with an old group's tenth and an old group's eighth is always with an old group's ninth. Newly registered players are classified according to their Elo ranking and are divided into groups according to a "serpentine" system, and then each new player group is assigned to a league group by drawing of lots (the number of players in the new groups should differ by no more than one). To handle withdrawals, I try to conform to the criteria, but if that is not possible, I draw lots.

Here is a simple example. Say the previous championship had an L3 split into 4 groups of 7 players each, with 12 new registrations and no withdrawals. Let “3l2g1” mean the third player in league 2 group 1 during previously championship. Underlined players are placed according drawing of lots (they could have been put in another group). Underlined players written in bold type determine the other underlined players' position. n1, n2, n3 are the new registrations who are classified according to their Elo ranking. So, we have :

  • League 1 : 1l1, 2l1, 3l1, 4l1, 5l1, 6l1, 1l2g1, 1l2g2, 2l2g1, 2l2g2
  • League 2 group 1 : 8l1, 9l1, 3l2g1, 4l2g2, 5l2g1, 6l2g2, 1l3g1, 1l3g3, 2l3g2, 2l3g4
  • League 2 group 2 : 7l1, 10l1, 3l2g2, 4l2g1, 5l2g2, 6l2g1, 1l3g2, 1l3g4, 2l3g1, 2l3g3
  • League 3 group 1 : 8l2g1, 9l2g2, 3l3g1, 4l3g2, 5l3g3, 6l3g4, 7l3g1, n2, n7, n10
  • League 3 group 2 : 7l2g2, 10l2g1, 3l3g2, 4l3g3, 5l3g4, 6l3g1, 7l3g2, n1, n8n9
  • League 3 group 3 : 7l2g1, 10l2g2, 3l3g3, 4l3g4, 5l3g1, 6l3g2, 7l3g3, n4n5, n12
  • League 3 group 4 : 8l2g2, 9l2g1, 3l3g4, 4l3g1, 5l3g2, 6l3g3, 7l3g4,  n3n6, n11