Rule 732.1 · Taking Shortcuts
When playing a game, players typically make use of mutually understood shortcuts rather than explicitly identifying each game choice (either taking an action or passing priority) a player makes.
Subrules
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.
Occasionally the game gets into a state in which a set of actions could be repeated indefinitely (thus creating a “loop”). In that case, the shortcut rules can be used to determine how many times those actions are repeated without having to actually perform them, and how the loop is broken.
Tournaments use a modified version of the rules governing shortcuts and loops. These rules are covered in the Magic: The Gathering Tournament Rules (found at WPN.wizards.com/en/rules-documents). Whenever the Tournament Rules contradict these rules during a tournament, the Tournament Rules take precedence.