Magic tournaments come in two basic styles, Constructed and Limited.
In Constructed tournaments, players bring their own cards in a pre-made deck. Decks must consist of no fewer than 60 cards, and no more than four of any one card. The basic land cards, however, may be used in any quantity.
A banned list of specific cards is maintained for each format. A list of banned cards can be found here.
In addition to the player’s 60+ card deck, a 15-card sideboard is permitted. Following the first game of a best-two-of-three match, each player is permitted to replace or add any number of cards from his or her sideboard or basic land cards. This allows players to modify their deck during a match to better deal with their opponent’s strategy.
- Standard uses cards from the most recent two blocks and the current core set.
- Modern uses cards from Eighth Edition forward.
Limited tournaments are based on a pool of cards which the player receives at the time of the event. Any number of basic lands may also be added to the deck. The decks in limited tournaments need only be 40 cards minimum; all the unused cards function as the sideboard. There is no 4-of-a-kind limit per card as there is in Constructed decks.
There are two common types of limited tournaments.
- Sealed deck: Players each receive five or six booster packs of 15 cards. They play with these cards and cannot trade or exchange them.
- Booster draft: Players each receive three booster packs of 15 cards. After being seated around a table, each player simultaneously opens one booster pack, selects a single card, and then passes the rest to the next player over. After all players have drafted fifteen cards, they each open their second pack, and drafting continues. Players examine privately the cards they receive; direct communication between drafters is not allowed. Once players have built their decks, they compete against the other players in the draft.