This term was first introduced via Problem-Solving Card Text in Legendary Collection 3: Yugi's World, in the updated card text of "Dark Necrofear".[Notes 1] It was then used in Abyss Rising, in the card text of the "Madolche" cards.
Cards considered to be in a particular player's possession are all of the following:
- cards on that player's side of the field
- cards in that player's hand, Main Deck, Extra Deck, and Graveyard
- that player's banished cards
- cards in the middle of being Summoned to that player's side of the field
- cards attached as Xyz Materials to an Xyz Monster(s) that player controls
- More recent reprints of "Dark Necrofear" no longer use "possession" as a term in their card texts, due to the activation conditions of "Dark Necrofear" having changed since then.
- Konami. Yu-Gi-Oh! Trading Card Game - Official Rulebook Version 10 (PDF). p. 53.