The Extra Deck (エクストラデッキ, Ekusutoradekki), previously referred to as Fusion Deck (
The Extra Deck is separate from the Main Deck and is placed face-down in the Extra Deck Zone. Unlike the Main Deck, the player that possesses it can look through it at any time. However, the contents of the Extra Deck are not public knowledge, so the opponent cannot look through face-down cards in the Extra Deck.
Per the "Maximum of 3 Rule", during Deck construction there can be at most 3 cards with the same name in a player's Main Deck, Extra Deck and Side Deck (combined). During Deck construction, there is a 15-card limit to the Extra Deck, regardless of how many Fusion Monsters, Synchro Monsters, or Xyz Monsters are included. However, Pendulum Monsters placed face-up in the Extra Deck during a Duel can cause the total size of the Extra Deck to be larger than would be allowed during Deck building.
If a Fusion Monster, Synchro Monster, or Xyz Monster would be returned to its owner's hand or Main Deck, it is instead moved to the Extra Deck, since Fusion Monsters, Synchro Monsters, and Xyz Monsters cannot exist in either the hand or the Main Deck. It is not necessary to shuffle the Extra Deck, even when a card specifies that the card is shuffled into the Extra Deck.
Anime and manga
Limits on the amount of cards that are stored in the Extra Deck in the anime and manga are not yet determined.
- It is also not clear at all times of the series if the Extra Deck exists in those Duels (such as early games shown just fuse monsters, without ever apparently pulling the Fusion Monster card from anywhere).
- It is also not clear at all times where the Extra Deck is kept. In some instances the cards are not seen to be played from anywhere but the Fusion Card is present on the Duel Disk such as with Jaden Yuki, while other Duelists such as Akiza Izinski can clearly be seen to have Extra Deck zones built into their Duel Disks. In Yu-Gi-Oh! ZEXAL, the Extra Deck is stored in a box on the Duelist's belt, while in Yu-Gi-Oh! ARC-V, Duel Disks are specifically shown to have a compartment to store their Extra Deck in.