In past Eye of the Stack articles I’ve covered very specific card interactions. One of those articles that has proved to be very popular covered what happens when you Lightning Bolt a Tarmogoyf, something that most people didn’t know exactly how it worked. Where did the confusion stem from? State-Based Actions. Let’s talk about those.
State-Based Actions (SBAs) are pretty awesome. They are the glue that holds Magic together and most of you might not even realize they exist. In the simplest of terms, SBAs check whether or not certain qualifications are met, like “Has a player lost the game?” or “Is this creature dead?” SBAs are pretty much habit and that’s why they’re not taught to new players. They are just too complex to explain to someone who has barely grasped the idea of how combat works.
To understand SBAs more thoroughly you need to understand the priority system. The priority system is the part of the game that gives players permission to do stuff. If it’s your turn and you just drew your card and are in Main Phase One, do you have priority? If you aren’t sure the answer to that, let me guide you.
Priority starts in turn order and lets you cast spells and activate abilities. Pretty straightforward right? The Stack (the place you put a spell when you cast it) uses the priority system to determine who can put more objects on the stack. So your friend casts Grizzly Bears and you want to use Essence Scatter to stop that bear from existing. How do you know when you can do this? That’s what priority does: it says when you can counter it.
So your opponent casts Grizzly Bears. Can you immediately counter it? Most likely yes, but when the active player casts a spell they immediately regain priority. Assuming they want to do nothing else after casting the Grizzly Bears then priority goes to you. This is when you can counter those dirty bears. How this would play out in game would be something like “I cast Grizzly Bears. Any responses?” The question “Any Responses?” is your opponent passing priority to you.
Knowing everything I just said, can you answer the question I posed earlier? “If it’s your turn and you just drew your card and are in Main Phase One, do you have priority?” If you answered “Yes!” then I’ve successfully taught you. If not, remember that Priority goes in turn order. If it is your Main Phase One then it is your turn. And remember, instants and activated abilities are the only thing you’re allowed to do out of turn, assuming you have priority. I could go deeper into this, but to simplify you gain priority during most phases. Whenever your opponent has priority you will have it too! It just depends on who’s turn it is. With all of that out of the way you are now ready to understand SBAs!
SBAs care about priority mainly because whenever a player gains priority, SBAs are checked. Let’s put that into an example.
During my main phase I cast Lightning Bolt, targeting my opponent’s Grizzly Bears. I put Bolt onto the stack, pass priority, and my opponent says “no responses.” Bolt resolves, marks 3 damage on Grizzly Bears, and it put into the graveyard. When will Grizzly Bears die?
If you said “immediately” then you are 99% right. The correct answer is “when priority is given to the active player”, but that’s more of a nuance since that immediately happens after a spell resolves. But that 1% difference is where the confusion with Tarmogoyf comes into play.
Tarmogoyf doesn’t have a static power and toughness. That’s the actual issue here. Goyf’s power and toughness are based on card types in the graveyard. So if I have a land in my graveyard and my opponent has a sorcery in their graveyard, Goyf is a 2/3. With 3 toughness my Lightning Bolt should be able to kill him, but look at the previous example and read it carefully. What happens before priority is regained? Lightning Bolt goes to the graveyard, meaning that if I cast Lightning Bolt on Goyf with 2 card types in the graveyard and neither types are instants, the next time SBAs are checked Goyf is a 3/4 with 3 damage marked on him because there are now 3 card types in the graveyard.
SBAs are also in control of Goyf’s power and toughness, but unlike the Stack, SBAs are simultaneous, meaning they all happen at once. His power and toughness are increased and damage is marked at the same time. Neither gains priority over the other. And that’s a big thing to understand when playing Magic.
I want to throw one more example at you, mainly because my co-author Luke wanted me to put it in this article, and that is the creature Maro and his interaction with Wheel of Fortune. So say I have Maro with 3 cards in hand. I cast Wheel of Fortune. What happens?
The correct answer is you discard 3 cards and draw 7 cards and Maro is now a 7/7. During the spell no priority is granted until the spell resolves. So before the spell Maro is a 3/3. When the spell is resolving he goes to 0/0 and then up to 7/7. Then priority is gained by the active player and SBAs are checked. You have 7 cards in hand, therefore Maro has 7 power and 7 toughness.
By no means are you going to have some crazy advantage in your next game of Magic but understanding the Priority System and State-Based Actions is an essential tool that you can use to your advantage either when deck-building, card evaluating, or just trying to impress your friends. I do hope this has been of some amount of help to you, and as always happy brewing!