Under the newly released Master Rules, each player (in official Duels and tournaments) must follow the guidelines below:
- Main Deck: No less than 40 cards. No more than 60 cards. A player is allowed to have any amount in between. Cannot contain any cards currently on the Forbidden section of the Forbidden/Limited Card List. Can only contain up to 3 copies of a card in the Deck and Side Deck combined. Cannot contain Fusion or Synchro Monsters.
- Side Deck: Must contain 15 cards exactly; no more, no less. A player may choose to not have a Side Deck at all. Cannot contain any cards currently on the Forbidden section of the Forbidden/Limited Card List. Can only contain up to 3 copies of a card in the Deck and Side Deck combined. Cannot contain Fusion or Synchro Monsters.
- Extra Deck: Can contain up to 15 cards. There is no minimum amount of cards that must be included in the Extra Deck. Cannot contain any cards currently on the Forbidden section of the Forbidden/Limited Card List. Can only contain up to 3 copies of a Synchro or a Fusion Monster.
