Cranial Insertion: All About Priority





Cranial Insertion
All About Priority
By Eli Shiffrin, Thijs van Ommen, and Jeff Vondruska


About a month ago, you could read about continuous effects on Cranial Insertion. It focused on a single topic of the rules. The plan is to do one such article every month. So guess what, the second article is today, and the topic is: *drum-roll* Priority.


What is Priority?

During many Magic games, both players will just play spells and abilities without getting in each others' way timing-wise. But what happens if both players want to do something at the same time? Or if both players want to wait and see what the other is going to do before making a move themselves? To deal with such questions, Magic needs timing rules. The timing rules are mostly described by a system of what is called priority.

To avoid the situations described above, only one player will be allowed to play anything at any given point in time. This player is said to have priority. That player can either use his right to play a spell or do something useful, or he or she can pass priority. While one player has priority, the other player (or players, if you're in a multi-player game) just have to wait.

In a cardboard-y Magic game, you usually don't play by the rules as strictly as that. There's no need to: most of the time, only one player is going to want to do something, so you don't need the timing rules at all. If you play Magic Online, you will be much more aware of these rules. The program makes you and your opponent wait on each other, depending on which player has priority. There's even a clock running while the game waits for your decision, so it suddenly becomes a lot more important for you to know when you have priority!


What do I need Priority for?

You need priority to do pretty much anything in a Magic game. Playing spells, activated abilities, lands and a lot of other things all require that you have priority. There are some corner cases and exceptions to keep in mind, though. Let's start with the basics.

Instants and most activated abilities can be played if you have priority, and not at any other time.

All the other card types (creatures, lands, sorceries, enchantments and artifacts) have additional requirements. Having priority isn't enough: it also needs to be the main phase of your turn, and the stack must be empty (which means that you can't use these cards to "respond" to another spell or ability).

Activated mana abilities can be played if you have priority, but the rules are a little looser here. Remember: an activated ability can be recognized because it's always of the form [cost]: [effect]. For example, ":symtap:: Prodigal Sorcerer deals 1 damage to target creature or player." has ":symtap:" as a cost, followed by a colon (:), followed by the effect of the ability. Now, an activated mana ability is an activated ability that also produces mana as part of its effect. It may do other things besides producing mana and still be a mana ability.

This is what the rules say about the timing of mana abilities.
From the CompRules:
411.2. A player may play an activated mana ability whenever he or she has priority, or whenever he or she is playing a spell or activated ability that requires a mana payment. A player may also play one whenever a rule or effect asks for a mana payment, even in the middle of playing or resolving a spell or ability.

Ignore this picture
While a spell or activated ability is being played, neither player has priority until the spell or ability is completely played. Similarly, when something is busy resolving, both players have to wait until it's done before someone receives priority again. The above rule allows you to play activated mana abilities at those times, even though you won't have priority then.

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Q: If I tap Forbidden Orchard for mana, do I get the mana first or does my opponent get the token first?

A: Normally, when one ability triggers on another being played, the triggered ability end up on top on the stack and will resolve first. But in this case, one of the abilities is a mana ability, which doesn't use the stack, but resolves immediately. You'll get the mana before your opponent gets the token.

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Once upon a time, there was a card type named "Mana Source" which behaved a lot like an activated mana ability, except that it was a spell, not an ability. However, this card type doesn't exist anymore. All these cards have been given errata and are now instants. If you want to know if any of your cards have received errata, you can look up the most current text in the Oracle reference. MTGSalvation's own card database can also tell you about these errata. For example, if you haven't heard of it already, click Oboro Envoy and see if you can spot the difference between the text on the card and the corrected text next to it. Smile

There's another category of actions a player may only if they have priority. This category is very appropriately called "special actions". Special actions don't use the stack. But the rules can explain that just as well as I can:
From the CompRules:
408.1i Special actions don't use the stack. The special actions are playing a land (see rule 408.2d), turning a face-down creature face up (see rule 408.2h), ending continuous effects or preventing delayed triggered abilities (see rule 408.2i), and suspending or ignoring continuous effects (see rule 408.2j).

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Q: I have a question.

A: As long as it doesn't involve interrupts... Those are just as obsolete as mana sources.

Q: Oh, nevermind then.

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It's family with Leonin Shikari, too.
Some spells or abilities don't like what the rules say about when you're allowed to play them. So they tell you to do something different. Examples are:
  • non-instants [card=Mystic Restraints]that want [card=Uncontrollable Anger]to be instants - these can be played any time you have priority, even if it's not the main phase of your turn and/or the stack isn't empty.
  • activated abilities that want to be sorceries - these work the other way around, and need to be played on an empty stack during your turn's main phase.
  • activated mana abilities that want to be instants - these can only be played at times ordinary activated abilities and instants could be played: when you have priority. Unlike mana abilities without this text, they can't be played during the announcement or resolution of something else. However, just like other mana abilities, they don't use the stack and resolve immediately.
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Q: Is there any way I can use Lion's Eye Diamond to play a spell I'm holding in my hand?

A: If Lion's Eye Diamond had been a normal mana ability that could be played like any other mana ability, then you'd have been able to announce the spell in your hand, put it on the stack, then use LED to get the mana for the spell's cost. The rest of your hand would be discarded, but that one spell would be safe.

As it is, you can't accomplish that (without the help of other cards). LED can only be played when you have priority, not during the announcement of another spell. You can't play that other spell unless you get the mana first, but if you play LED's ability first, then the spell will no longer be in your hand.

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There are some actions that you may take during a game that the rules described above don't deal with. For example, if you use Isochron Scepter to create a copy of the imprinted instant card, then you'll get to play that copy right then, while the Scepter's ability is still busy resolving. While you are resolving a spell or ability, you just carry out the instructions it gives you.

And there's also Serum Powder, which allows you to make decisions and move cards around before any player has receive priority, even before the first turn begins.... Isn't Magic a wonderful game? :tongue2:


How do I get Priority?

We've seen that priority is a pretty useful thing to have now and then if you want to do anything useful during a game. So, when exactly does a player get priority? Well, you needn't worry about that, because priority is all over the place. For starters, if you look through rules 301-314 of the CompRules, then you'll find the following sentence appear about ten times:
Then the active player gets priority and players may play spells and abilities.
It always starts with the active player (that is the one whose turn it is) receiving priority. But before he actually gets to use it to play stuff, the rules want to do some maintenance work. This is where state-based effects are checked, and where triggered abilities may go on the stack if they triggered. I'll deal with these things in more detail in the next section.

A player with priority can either use it (to play a spell or an activated ability, or to take a special action), or pass priority to the next player. If the player doesn't pass priority, he or she will again be the first to receive priority as soon as the spell, ability or special action is played. In the case of a spell or ability (other than a mana ability), that means that the thing has been put on the stack, but hasn't resolved yet. Mana abilities and special actions do take effect immediately. So essentially, once a player has priority, he or she can play as many spells and other things as can be paid for before passing priority.


Goblins make great explosives
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Q: I don't understand this card Goblin Cannon. Can I deal more than 1 damage with it?

A: Yes, you can. The trick is to not pass priority, but instead to activate the Cannon as many times as you want back-to-back. The first ability that resolves will deal 1 damage and cause the Cannon to be sacrificed. Each subsequent one will try to do the same. The Cannon is gone, but the ability will still do as much as possible and deal 1 damage to its target.

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At some point, all players will presumably be done and both will only want to pass priority. When all players pass priority in succession, the game moves on. "In succession" means that everyone passed priority and nothing else was done in between: no spells or abilities were played, and no special actions were taken. The game won't move on until this has happened. The result of that rule is that all players will always receive priority and get the opportunity to do something with it before the game moves on.

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Q: My opponent controls a morphed face-down creature, and I try to Devour in Shadow it. I pass priority, then my opponent turn his creature face up. It turns out to be a Blistering Firecat. Then my opponent passes priority again. It'd rather not take the life loss from my own Devour in Shadow and kill the cat some other way in response, but my opponent argues that he didn't add anything to the stack, so Devour in Shadow should resolve right away. Is he right?

A: No, he isn't. Even though the special action of using morph to turn a creature face up doesn't use the stack, it still broke the "succession". You'll receive priority again before your spell resolves, giving you the opportunity to find a solution to your impending life loss.

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What does "the game moves on" mean, exactly? In case there's anything on the stack, whatever is on top (that is, whatever was added to the stack last) will resolve first. Then the active player receives priority and the whole thing starts anew. In case there's nothing on the stack when all players pass in succession, the current step or phase of the turn ends.

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Q: My opponent played Grab the Reins with entwine on my creature. Then he waited for me to respond. I said I didn't have any responses, but then he played Devouring Rage targeting my creature, sacrificing enough Spirits that my own creature would kill me. I don't believe he can do this. Who's right?

A: You are. By waiting for your response, your opponent signified that he has passed priority to you. When you passed priority back, you had both passed priority in succession, and Grab the Reins would resolve before your opponent could play Devouring Rage. To do this right, your opponent should have played both his spells without passing priority in between. This could win him the game, but it might be a pretty big risk: if you can counter Grab the Reins, then he'll just have done you a favor by sacrificing his Spirits to give your creature a power boost.

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Q: My opponent plays Kokusho, the Evening Star which I want to counter, but I don't have any counterspells in my hand. I do have a Gifts Ungiven, though. Can I play Gifts Ungiven, let it resolve to get a bunch of counterspells from my library so that at least one will end up in my hand, and use that to counter the Dragon before he resolves?

A: That's a perfectly valid play. After Gifts Ungiven resolves, the active player will receive priority. The game won't move on (which would mean that Kokusho would resolve, because he's now on top of the stack) until you've also had priority. You'll get the chance to use your new-found counterspell on Kokusho right then.

This situation will sometimes lead to arguments, because it used to be different before Sixth Edition rules. Then, once the top item of the stack was allowed to resolve, the entire stack would resolve before anyone got priority again. But that's no longer how it works.

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Added text in the Oracle:
"Play Waylay only during combat."
There are two steps in a turn where things are a little odd. The first is the untap step. Nobody receives priority during the untap step, so the earliest opportunity in a turn to play anything will be in the upkeep step. This also means that the game's "maintenance work" of checking state-based effects and putting triggered abilities on the stack isn't done until the upkeep. If an ability triggers during the untap step, it'll be made to wait for the upkeep before it gets put on the stack.

The other step where the timing rules show some unusual behaviour is during the cleanup step. The last phase of a turn (the end phase) has two steps: the end of turn step, and the cleanup step. In the end of turn step, any triggered abilities that trigger "at end of turn" go on the stack, and the active player receives priority. That's pretty straightforward. Then, in the cleanup step, the active play has to discard down to seven cards in hand, all damage is removed from permanents, and all continuous effects that were supposed to end this turn, end. Now you'd expect the active player to receive priority again, like in pretty much every other step in the turn. Yet that's not always the case. The game does go ahead and do its "maintenance work" regarding state-based effects and triggered abilities. But only if there were actually any state-based effects to apply or triggers to put on the stack does the active player gain priority.

If the active player doesn't gain priority, then the turn is over and the next player's turn starts. If he or she did receive priority, then all the usual stuff happens until the players pass priority in succession on an empty stack. And then another cleanup step begins. Smile This strange behaviour can lead to even stranger situations. For example, if an "at end of turn" trigger is created during the cleanup step, it won't go on the stack until the next turn's end of turn step. This led to abuse of the card Waylay before it was given errata. The card was intended to give you some surprise blockers, but if you played it during your opponent's cleanup step, you'd get three cheap 2/2's to attack with on your own turn! Note that this only works for "at end of turn" triggered abilities, and not for "until end of turn" or "this turn" continuous effects!


State-Based Effects

I've talked about state-based effects a lot this article, so I suppose this might be a good time to show you what they are. In general, they look out for and fix all sorts of situations that aren't supposed to happen. For example, they check for creatures with lethal damage and move those over to the graveyard. The best way to tell you what they do is simply to copy-paste the rules here:
From the CompRules:
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 A local enchantment that enchants an illegal or nonexistent permanent is put into its owner's graveyard.

420.5e If two or more permanents with the same name have the supertype legendary, 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 that equips an illegal or nonexistent permanent stops equipping that permanent but remains in play.

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Q: Do tokens that die trigger Promise of Bunrei's ability?

A: Promise of Bunrei triggers when a creature goes to the graveyard. State-based effect 420.5f causes a token in the graveyard to simply stop existing. However, before state-based effects are checked, the token will be in the graveyard for a small window of time. No matter how short its stay is, the game knows that the token went from play to the graveyard, so Promise of Bunrei gets to trigger.

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That's it for another week. Next week, Eli will discuss his experiences at the Saviors of Kamigawa prerelease. If you have any quesions regarding the new expansion, send them to one of us, and they might just end up in Cranial Insertion! Well, that's up to Moko, of course. But Moko seems to like Saviors, so your chances are pretty good.

-Thijs van Ommen, The Netherlands

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