From Bulbapedia, the community-driven Pokémon encyclopedia.
The Pokémon World Championships are an annual event staged by the Play! Pokémon organized play division of The Pokémon Company International (formerly known as Pokémon USA). As part of taking over the licensing of the Trading Card Game from Wizards of the Coast, a division of Hasbro, the first World Championships were staged in 2004.
An annual invitational-only event held in August of a given year, players are chosen on overall ratings, national champions and past performances in the previous year's World Championships.
Trading Card Game
The championships are staged utilizing that year's Modified Format Set over three days with a last chance qualifier (known to players as "The Grinder") on the Friday to fill seats left vacant for various reasons (no travel, local qualifiers) until all seats are filled. The second day is limited to Swiss Pairings over a set number of rounds, and the top players (16 each in the Junior and Senior Divisions, as well as the top 32 in the Masters division) move onto the Sunday rounds. The format for this final is single elimination, until the finals, which are a best two matches out of three to decide the World Champion. There are three divisions: Junior (known as the 10 Years Old and Under Division until 2006), Senior (known as the 11 to 14 Year Old Division until 2006) and Masters (called the 15 Years and Older Division until 2006).
Modifed Format Sets
The format for the Video Game Championships, first staged in 2009 in San Diego, California is virtually the same as the TCG counterparts with winners comprised of those in National tournament play. In 2010, a Last Chance Qualifier was held on Friday to fill all vacant spots. In 2011, a Masters age Division was added to parallel the TCG. The most recently released Pokémon game (which is currently Pokémon X and Y) is used for battles. The event format consists of swiss rounds, followed by a single elimination tournament. In 2009, the top two advanced to play the finals on Sunday, whereas since 2010, the top eight advance to play in a head-to-head single elimination event to decide the World Champions.