In a nutshell
- State-based actions are things the game automatically takes care of to simplify the game state.
- The game checks for state-based actions every time a player would get priority. If state-based actions are performed, the game repeats this process until no further state-based actions are performed before the player actually gets priority.
- State-based actions are also performed in the cleanup step after all the turn-based actions (discarding to maximum hand size, damage wearing off, etc.) in that step are performed. If any state-based actions are performed at this time (or if any triggered abilities go on the stack), players will get priority. Once the stack is empty and all players pass in priority, another cleanup step will begin.
- All applicable state-based actions are performed at the same time.
- If multiple state-based actions would have the same result at the same time, a single replacement effect will replace all of them.
- If a state-based action makes a permanent leave the battlefield at the same time as other SBA’s are performed on it, that permanent’s last known information is derived from the game state before any SBA’s were performed.
These are the state-based actions. Don’t worry about trying to memorize all of these. Rather, note what types of things are state-based actions and be able to say what the most common ones are.
- Losing the game
- If a player has 0 or less life, he or she loses the game.
- If a player attempted to draw a card from a library with no cards in it since the last time state-based actions were checked, he or she loses the game.
- If a player has ten or more poison counters, he or she loses the game.
- In a Two-Headed Giant game, if a team has 0 or less life, that team loses the game.
- In a Two-Headed Giant game, if a team has fifteen or more poison counters, that team loses the game.
- Vanishing act
- If a token is phased out, or is in a zone other than the battlefield, it ceases to exist.
- If a copy of a spell is in a zone other than the stack, it ceases to exist. If a copy of a card is in any zone other than the stack or the battlefield, it ceases to exist.
- Killing or destroying
- If a creature has toughness 0 or less, it’s put into its owner’s graveyard. Regeneration can’t replace this event.
- If a creature has toughness greater than 0, and the total damage marked on it is greater than or equal to its toughness, that creature has been dealt lethal damage and is destroyed. Regeneration can replace this event.
- If a creature has toughness greater than 0, and it’s been dealt damage by a source with deathtouch since the last time state-based actions were checked, that creature is destroyed. Regeneration can replace this event.
- If a planeswalker has loyalty 0, it’s put into its owner’s graveyard.
- If a player controls two or more legendary permanents with the same name, that player chooses one of them, and the rest are put into their owners’ graveyards. This is called the “legend rule.”
- If two or more permanents have the supertype world, all except the one that has had the world supertype 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.”
- If an Aura is attached to an illegal object or player, or is not attached to an object or player, that Aura is put into its owner’s graveyard.
- Fixing bad attachments
- If an Equipment or Fortification is attached to an illegal permanent, it becomes unattached from that permanent. It remains on the battlefield.
- If a creature is attached to an object or player, it becomes unattached and remains on the battlefield. Similarly, if a permanent that’s neither an Aura, an Equipment, nor a Fortification is attached to an object or player, it becomes unattached and remains on the battlefield.
- Fixing counters
- 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.
- If a permanent with an ability that says it can’t have more than N counters of a certain kind on it has more than N counters of that kind on it, all but N of those counters are removed from it.
- SBA’s for casual variants (These won’t be on a judge exam.)
- In a Commander game, a player that’s been dealt 21 or more combat damage by the same commander over the course of the game loses the game.
- In an Archenemy game, if a non-ongoing scheme card is face up in the command zone, and it isn’t the source of a triggered ability that has triggered but not yet left the stack, that scheme card is turned face down and put on the bottom of its owner’s scheme deck.
- In a Planechase game, if a phenomenon card is face up in the command zone, and it isn’t the source of a triggered ability that has triggered but not yet left the stack, the planar controller planeswalks.
Q: Amy controls a Maro and has 4 cards in hand. She casts a Winds of Change. What happens?
A: Amy shuffles her hand into her library. At this point, she has 0 cards in hand, so Maro has 0 toughness. State-based actions are not performed during the resolution of spells and abilities, though, so it is safe. Amy draws for Winds of Change, then Winds finishes resolving and is put into her graveyard. At this point, the active player is about to get priority, so state-based actions are performed. Maro’s toughness is now greater than 0, so it is not put into Amy’s graveyard.
Note: This is one difference between triggered abilities and state-based actions. A triggered ability that said “when a player has no cards in hand…” like Veiled Crocodile would trigger here.
Q: Nicole controls an Elesh Norn, Grand Cenobite. Amy wants to cast a Sakura-Tribe Elder from her hand and sacrifice it immediately to get a basic land. Can she?
A: No. Anytime a spell resolves, before players get priority, the game performs state-based actions. In this case, that includes putting Sakura-Tribe Elder into its owner’s graveyard, since it will have 0 or less toughness the moment it’s in play. Since it dies before Amy gets priority, she can’t sacrifice her elder for its ability.
Q: Amy casts a Pyroclasm while Nicole controls a Goblin Chieftain and a Goblin Warchief. What happens?
A: Pyroclasm causes 2 damage to be marked on each creature. Then, before Amy gets priority, the game checks for state-based actions. Goblin Chieftain is a 2/2 with 2 damage on in, so it is destroyed. Then, the game checks for SBA’s again. It will see that Goblin Warchief is now a 2/2 with 2 damage marked on it, so it’s destroyed. The game checks for SBA’s one more time, and this time there are none to perform, so Amy gets priority.
Q: Amy blocks a 3/3 deathtouch creature with a 2/2 creature that can regenerate. How many regeneration shields will her 2/2 need to survive?
A: Only one. Both the lethal damage and the deathtouch damage would destroy the creature at the same time. This means that it only takes a single replacement effect to replace them both.
Note: This is a reversal from previous rulings, so you may run into players who disagree. Under previous rules, deathtouch was a triggered ability that triggered on damage being dealt, so it would generate a discrete destruction event. With the current rules for deathtouch, this scenerio works as described above.
Q: Amy casts Zap targeting Nicole while Nicole has 1 life and Amy’s library is empty. What happens?
A: Zap resolves, reducing Nicole to 0 life. Amy is unable to draw a card as Zap instructs her to. The next time state-based actions are performed, there will be two applicable actions to perform. Both Amy and Nicole will lose the game, for having attempted to draw a card from an empty library and for having 0 life. Because both players are losing the game at the same time, it is a draw.
Q: Amy controls Xenagos, the Reveler and casts a Xenagos, god of Revels. What happens?
A: A lot of reveling. Even though these two permanents both represent the same storyline character, the game doesn’t have any problems with both of them being on the battlefield at the same time. The legend rule doesn’t kick in because Xenagos, the Reveler isn’t the same name as Xenagos, god of Revels.
Q: Amy casts a Turn on her Zombie Outlander, then casts Rancor targeting it. What happens in the end of turn?
A: In the cleanup step, Turn’s “loses all abilities” effect will end, and Zombie Outlander will have protection from green again. After that, the game will check for state-based actions, and Rancor will be put into Amy’s graveyard. This will cause its triggered ability to trigger. Both players will be able to respond to this before it resolves. After this cleanup step, because a state-based action was performed (and because a triggered ability triggered), there will be another cleanup step before the game progresses to the next turn.
Q: Amy controls a Young Wolf with a +1/+1 counter on it. Nicole casts a spell that puts 2 -1/-1 counters on it. Does Young Wolf’s undying trigger?
A: No. There are two state-based actions that are applicable here. One wants to remove a +1/+1 counter and a -1/-1 counter from Young Wolf, and the other wants to put it into the graveyard for having 0 toughness. These are both performed at the same time. Because one SBA is making Young Wolf leave the battlefield at the same time as other SBA’s are being performed on it, the wolf’s last known information is taken from the game state before any SBA’s were performed. At that time, it had a +1/+1 counter on it, so undying won’t trigger.
Q: Amy casts Momentary Blink on her spirit token. What happens?
A: If you’re going just by what you know about state-based actions, you should have said that it comes back just fine. SBA’s aren’t performed in the middle of the casting or resolution of a spell or ability, so the token would return before SBA’s made it vanish. Alas, the rules team didn’t like that, so they made up a rule to prevent it from happening. “A token that has left the battlefield can’t move to another zone or come back onto the battlefield. If such a token would change zones, it remains in its current zone instead. It ceases to exist the next time state-based actions are checked” [CR 110.5g].
Q: What does the word “World” signify on cards like The Abyss?
A: That’s not just wacky old-school templating (although it would say “World Enchantment” if it were printed today)! This word signifies that The Abyss is subject to the “world rule.” If there are ever two The Abysses on the battlefield at once (or any two World permanents, not even necessarily the same one), they are all put into the graveyard except the one that most recently gained the world supertype (usually the one that most recently entered the battlefield). If there is a tie, they all die.
Q: Amy controls a Birthing Pod and a Wall of Roots with 4 -0/-1 counters on it. Can she activate pod by making mana with the Wall of Roots and then sacrificing it?
A: Yes. Wall of Roots has a mana ability, which means that it can be activated during the process of activating Birthing Pod’s ability. This will cause the wall to have 0 toughness, but it won’t be put into its owner’s graveyard immediately. That doesn’t happen until the next time state-based actions are performed, which isn’t until after the process of activating pod’s ability is complete. Before that happens, Amy will have to sacrifice a creature, and the about-to-die Wall of Roots is a valid candidate for that job.