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The Extra Deck (Japanese: エクストラデッキ Ekusutora Dekki, abbreviated
The Extra Deck is separate from the Main Deck and is placed face-down in the Extra Deck Zone. Like the Main Deck, the number of cards in the Extra Deck is public knowledge. Unlike the Main Deck, a player may look through their own Extra Deck at any time. The face-down contents of the Extra Deck are not public knowledge, so a player may not look through face-down cards in their opponent's Extra Deck; however, the face-up cards in the Extra Deck are public knowledge, so either player may look through them at any time.
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, the Extra Deck has a maximum size of 15 cards (including all Fusion, Synchro, Xyz, and Link Monsters combined). However, Pendulum Monsters placed face-up in the Extra Deck during a Duel can cause the total size of the Extra Deck to exceed the maximum size permitted during Deck construction.
If a Fusion, Synchro, Xyz, or Link Monster would be returned to the hand or Main Deck, it is instead returned to the Extra Deck (face-down), since Fusion, Synchro, Xyz, and Link Monsters cannot exist in the hand or the Main Deck. It is not necessary to shuffle the Extra Deck, even when a card specifies that the card would be shuffled into the Deck.
Prior to New Master Rule, Extra Monster Zones did not exist. Monsters Special Summoned from the Extra Deck could be Special Summoned to any appropriate Monster Zone.
Under Master Rule (April 1, 2020 update)—the current rules, Pendulum Monsters and Link Monsters Special Summoned from the Extra Deck must be Special Summoned to a Main Monster Zone pointed to by a Link Monster or an Extra Monster Zone.
Anime and manga
Limits on the number 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 even exists; in many early Duels, the players seem to simply 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 Yu-Gi-Oh! GX, Fusion Monster Cards are not seen to be played from anywhere, but the Fusion Monster Card is present on the Duel Disk after it is Summoned.
- In Yu-Gi-Oh! 5D's, Akiza Izinski can clearly be seen to have an Extra Deck Zone built into her Duel Disk. Yusei Fudo and Jack Atlas's Extra Decks are stored with their Main Decks; both are shown adding "Stardust Dragon" to their Main Decks before a Duel.
- In Yu-Gi-Oh! ZEXAL, the Extra Deck is stored in a box on the Duelist's belt.
- In Yu-Gi-Oh! ARC-V, Duel Disks are specifically shown to have an Extra Deck Zone compartment.
- In Yu-Gi-Oh! VRAINS, Yusaku Fujiki adds the "Borreload Furious Dragon" that Roken Kogami gives him to his Main Deck. When "Firewall Dragon", a Link Monster, was resonating in the anime, a slot on the back of his Duel Disk glows blue, suggesting it may be the Extra Deck. During his final Duel with Ai, Playmaker used exactly 15 Extra Deck monsters.
- Konami. Yu-Gi-Oh! Official Card Game - Perfect Rulebook 2015. p. 43.
- Yu-Gi-Oh! GX episode 06565: "No Pain, No Game"
- Yu-Gi-Oh! 5D's episode 0044: "A Blast From the Past: Part 1"
- Yu-Gi-Oh! 5D's episode 02323: "Duel of the Dragons, Part 1"