When does a player transition from one phase or step to another?

A player transitions from one phase or step to another when the stack is empty and all players pass in succession. This is a fundamental aspect of how game actions resolve in Magic: The Gathering.

During a player's turn, they can play spells, activate abilities, and pass priority to other players. When a player passes priority, it indicates that they do not want to take any further actions at that moment. The stack is the area where spells and abilities are placed, and it resolves in a "last in, first out" manner. When the stack is empty, it means there are no spells or abilities waiting to resolve. If all players consecutively pass priority, it tells the game that there are no more actions to take, allowing the game to move to the next phase or step.

This transition is critical, as it ensures that during each part of a player's turn, all opportunities for interaction or response are considered before moving on. It creates a rhythm within the game, promoting strategic planning and timing in gameplay.