DCI (Wizards of the Coast)

The DCI (formerly, Duelists' Convocation International) is the official sanctioning body for competitive play in Magic: The Gathering and various other games produced by Wizards of the Coast and its subsidiaries, such as Avalon Hill. The DCI provides game rules, tournament operating procedures, and other materials to private tournament organizers and players. It also operates a judge certification program to provide consistent rules enforcement and promote fair play.

In order to play in sanctioned events, players must register for membership and receive a DCI number (PIN). The DCI maintains a global player ratings database (formerly based on a variation of the Elo rating system) and members have access to their entire tournament history online. If a member commits frequent or flagrant rules infractions, his or her membership can be suspended for variable amounts of time depending on the severity, from one month to lifetime.

The DCI sanctions tournaments for a variety of games. As of 2009, the DCI has sanctioned more than two million Magic tournaments. Unlike those of many other game producers, a significant proportion of DCI events are organized and run by independent businesspeople and hobbyists, as opposed to retailers.

The DCI maintains rules and assigns players ratings for three basic categories in Magic: Constructed, Eternal, and Limited. A fourth rating category, Composite, is the average of a player's Constructed and Limited ratings. Each category supports a number of related tournament formats. A player's tournament performance in one of the categories does not affect their rating or ranking in the others, except Composite. The DCI has recently introduced a new rating category, called Total rating. This rating will replace most of the existing individual ratings at the beginning of 2010. Although no rating category will cease to exist, Total will replace the other categories for rating-based invitations and byes.

Separate groups of rankings are maintained for team and multiplayer variants. Sanctioned team and multiplayer uses teams composed of two or three players. There are several team and multiplayer variants, each given its own ratings category. Rules are also provided for other multiplayer variants, but only the formats mentioned above are ranked.

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