to four hours, and players usually meet once every week. Local Tournaments: Local tournaments may be held by an organizer sanctioned by Play! Pokémon. Prizes and entry fees vary depending on the number of competitors, and the tournaments can either be free to enter or require an entry fee at the discretion of the organizer. The tournaments are typically single-elimination, Swiss-system, or a combination of both (i.e. Swiss followed by single elimination rounds). Sometimes, the tournaments apply an "Age Modified Swiss" system, a variation of Swiss in which a player's age takes priority over the player's record when the players are paired. Players may also be categorized by age if there is a significant number of players. Categories range from Junior (ages 12 and under), Senior (ages 13–15) and Master (ages 16 and over). When the tournament is complete, players are given a rating based on their performance following the Elo rating system. Prerelease Tournaments: Prerelease Tournaments are Trading Card Game events in which players play with cards from an expansion set that would not have been released until up to two weeks later. The typical entry fee is $20–35 and each player would be given six booster packs, a special promo card, and a set of sleeves that are themed after the new set. Each player builds a 40-card deck using the cards opened out of the six packs (not including basic Energy cards, which are provided at the event). At the end of each prerelease, players receive three extra booster packs. Players may also have the option of playing in a 'Theme Deck challenge' instead of the Prerelease event, where they play for a themed deck and 4 booster packs. Pokémon Championship Series Tournaments part of the Pokémon Championship Series (i.e. Premier Tournaments) are competitive tournaments which reward players with Championship Points based on their finishing position at the tournament. Players earn an invitation to compete in the annual Pokémon World Championships should they accumulate enough points above a pre-determined threshold at the end of the season. The threshold depends on the type of game played, the player's age division and the region in which the player is registered in, and may change at the start of each season. Premier Tournaments vary in size, scale and frequency, and can be classified into any one of the event types as shown in the following table. Entry-level and mid-level events