Rule 729.1 · Subgames

A “subgame” is a completely separate Magic game created by an effect. Essentially, it’s a game within a game. The “main game” is the game in which the spell or ability that created the subgame was cast or activated. The main game is temporarily discontinued while the subgame is in progress. It resumes when the subgame ends.

No effects or definitions created in either the main game or the subgame have any meaning in the other, except as defined by the effect that created the subgame. For example, the effect may say that something happens in the main game to the winner or loser of the subgame.