Xyz Summoning is a special game mechanic in the Yu-Gi-Oh! trading card game that allows players to summon powerful monsters known as Xyz Monsters. This process involves overlaying two or more monsters of the same level on top of each other, creating a new monster that can be used in battle. The number of monsters used for the summoning is indicated by the rank of the Xyz Monster. To perform an Xyz Summon, players must have the required number of monsters on the field. Once the monsters are stacked, they are treated as materials for the Xyz Monster, which can then be activated for its unique effects. This mechanic adds strategic depth to the game, allowing for various combinations and tactics.