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.
July 25, 2025 · Edge of Eternities
rule 729.1a not present in this release
April 4, 2025 · Tarkir: Dragonstorm
The phrases “day becomes night” and “night becomes day” refer to the game losing the first designation and gaining the second one.
March 8, 2024 · Fallout
The rules for taking shortcuts are largely informal. As long as each player in the game understands the intent of each other player, any shortcut system they use is acceptable.