State-based effects

420. State-Based Effects

• 420.1. State-based effects are a special category that apply only to those conditions listed below. Abilities that watch for a specified game state are triggered abilities, not state-based effects. (See rule 404, “Triggered Abilities.”)
• 420.2. State-based effects are always active and are not controlled by any player.
• 420.3. Whenever a player would get priority (see rule 408, “Timing of Spells and Abilities”), the game checks for any of the listed conditions for state-based effects. All applicable effects resolve as a single event, then the check is repeated. Once no more state-based effects have been generated, triggered abilities go on the stack, and then the appropriate player gets priority. This check is also made during the cleanup step (see rule 314); if any of the listed conditions apply, the active player receives priority.
• 420.4. Unlike triggered abilities, state-based effects pay no attention to what happens during the resolution of a spell or ability.
  • Example:
    A player controls a creature with the ability “This creature’s power and toughness are each equal to the number of cards in your hand” and plays a spell whose effect is “Discard your hand, then draw seven cards.” The creature will temporarily have toughness 0 in the middle of the spell’s resolution but will be back up to toughness 7 when the spell finishes resolving. Thus the creature will survive when state-based effects are checked. In contrast, an ability that triggers when the player has no cards in hand goes on the stack after the spell resolves, because its trigger event happened during resolution.
• 420.5. The state-based effects are as follows:
  • 420.5a A player with 0 or less life loses the game.
  • 420.5b A creature with toughness 0 or less is put into its owner’s graveyard. Regeneration can’t replace this event.
  • 420.5c A creature with lethal damage, but greater than 0 toughness, is destroyed. Lethal damage is an amount of damage greater than or equal to a creature’s toughness. Regeneration can replace this event.
  • 420.5d An Aura attached to an illegal permanent or not attached to a permanent is put into its owner’s graveyard.
  • 420.5e If two or more legendary permanents with the same name are in play, all are put into their owners’ graveyards. This is called the “legend rule.” If only one of those permanents is legendary, this rule doesn’t apply.
  • 420.5f A token in a zone other than the in-play zone ceases to exist.
  • 420.5g A player who was required to draw more cards than were in his or her library since the last time state-based effects were checked loses the game.
  • 420.5h A player with ten or more poison counters loses the game.
  • 420.5i If two or more permanents have the supertype world, all except the one that has been a permanent with the world supertype in play for the shortest amount of time are put into their owners’ graveyards. In the event of a tie for the shortest amount of time, all are put into their owners’ graveyards. This is called the “world rule.”
  • 420.5j A copy of a spell in a zone other than the stack ceases to exist. A copy of a card in any zone other than the stack or the in-play zone ceases to exist.
  • 420.5k An Equipment or Fortification attached to an illegal permanent becomes unattached from that permanent. It remains in play.
  • 420.5m A permanent that’s neither an Aura, an Equipment, nor a Fortification, but is attached to another permanent, becomes unattached from that permanent. It remains in play.
  • 420.5n If a permanent has both a +1/+1 counter and a -1/-1 counter on it, N +1/+1 and N -1/-1 counters are removed from it, where N is the smaller of the number of +1/+1 and -1/-1 counters on it.
  • 420.5p A planeswalker with loyalty 0 is put into its owner’s graveyard.
  • 420.5q If two or more planeswalkers that share a planeswalker type are in play, all are put into their owners’ graveyards.