Rules Processing #4 – Priority & The Stack

Welcome once again to a totally on schedule Rules Processing, where this time we’re going to dive into priority and the stack. I did consider splitting these up into separate articles, but after getting some opinions from the other members of the Crystarium I went into a deep, meditative state to consider and reflect. I emerged, with the knowledge that keeping them together made the most sense. In my previous article I covered how priority worked in the Attack Phase, which does mean I’ve covered a good amount of how priority works but there is still more to dig in to and clarify, although there will of course be some overlap. Before we get into the article proper today, it wouldn’t be a Rules Processing article if I didn’t digress a bit first. We return once again to the ongoing saga of Yoh trying to become a FFTCG judge, that’s right, it’s time for the next eagerly anticipated chapter in this two-decade spanning (okay, maybe that’s an exaggeration) story!

If you’ve been following my Rules Processing article from the start, you’ve seen me talk about my journey to become a FFTCG judge, if not, I won’t recap, I’ll just tell you it’s been a wild ride. This chapter of our story takes us to the Winter Cup way, way, back in December of 2019. I decided, since SE staff were present, to actually just ask and get some answers. This led to a discussion with the EU representative where they explained that combination of being busy with events and the fact-checking of some stuff had held up my application. To cut a long story short, I finally now have confirmation from the EU rep that I am an official judge. Bit underwhelming of a finish, huh? Hold on.

*Fireworks, loud applause, and massive excitement*

Better? So, yes, finally the story has come to an end. Don’t worry though because now we have a brand new story. Yoh has become a judge but hasn’t received his judge polo shirt (why can’t it be a t-shirt? Urgh). Look forward to the next thrilling instalment of this new story next time (not really, this is actually the real end of me talking about this!).

Onwards we go with the article content you came for!

Priority

It’s somewhat of a toss-up as to whether I should first talk about priority or the stack. It’s really hard to talk about one without the other being involved in some way, but I’m going to start with priority for two reasons:

I’ve already covered some of priority in my previous article.
The stack can’t function properly without priority, but priority does function without players using the stack.

So, let’s begin by asking, what is priority? Priority is, in the simplest terms, the way to identify who can play cards, or use abilities, at a specific point in a turn, and, beyond that, there are rules that determine what types of cards a player can play depending on whose turn it is (i.e. is it your turn or your opponent’s), and which phase it is during that turn.

Think of a group of people sitting around a campfire. Each will get the chance to tell a (hopefully) riveting ghost story. If everyone starts telling their story at the same time it would be utter chaos. There needs to be a way to determine the order of who gets to talk. The simplest way to determine an order is to go around either clockwise or anti-clockwise. Let’s go with clockwise. Now, how do we determine who talks? Simple. The talk stone. A magical idea that definitely wasn’t just someone grabbing the nearest thing. Then, you just give the stone to whomever, let’s not stress and get too into the weeds here, it’s just an example, calm down roll some dice or something, Idk. With that all together, the first person with the stone tells their story. Then the next, and the next, and the next, and so on. Nice and orderly. That’s what priority is like, an orderly way to determine when each player can do certain things.

Hopefully you now have a basic concept for what priority is, however this is where things get a little more complicated to unwrap. Why? In the example above, when someone has the stone, what they can do is always the same (tell a ghost story), however what a player can do when they have priority varies depending on the phase and if they are the turn player or not. Don’t worry, it’s not actually that complicated, it’s just not as simple when compared to the example above.

I think the thing to do first before we get into this is to quickly break down the phases of a turn:

Active Phase
Draw Phase
Main Phase (1)
Attack Phase (which is the only phase that is broken up into separate steps)
Main Phase (2)
End Phase

It’s worth quickly mentioning that a player cannot skip these phases (although you can skip steps in the Attack Phase), you have to proceed through all of them in a given turn. The only way a phase will be skipped is by card effects. This is very important and the why of that will likely become clearer as we go on, but the gist is that the non-turn player always gets plenty of opportunity to use cards during the turn player’s turn (even if they’d prefer to just skip through phases!).

Now, of those 6 phases listed, priority is only given in the Main Phases, the Attack Phase and the End Phase (although as I’ll get into you can’t actually do anything in the End Phase with priority, it’s just some fairly stupid rules design).

Okay, so what can you do with priority? Well, let’s start with if you’re the non-turn player, because during the Main Phases and the Attack Phase, what the non-turn player can do is exactly the same, they can perform the following actions as many times as they want and/or are able to:

Activate an action or special ability.
Cast a Summon.
Play a Character via Back Attack.

Each time the non-turn player does one of these actions, priority returns to them. I’ll get to priority passing and what happens when you gain priority in just a bit, for now, let’s continue on with what the turn player can do with priority.

The turn player can perform the exact same actions as the non-turn player in the Attack Phase, what differs is what the turn player can do during the Main Phases. This difference is that, during a Main Phase, the turn player may play a Character from their hand, as long as the stack is empty (as in there are no Summons, or auto, action, or special abilities on it). That’s it. See, told you it wasn’t all that complicated.

Let’s now talk about how you gain priority and also how you pass priority.

The turn player gains priority at the beginning of the Main Phases, the Attack Preparation Step, and the End Phase. The turn player also gains priority in the Attack Declaration Step after an attack is declared, the Block Declaration Step after the non-turn player declares a blocker or chooses to not block, and the Damage Resolution Step after player damage or battle has been resolved. The non-turn player then gains priority for the first time in each of the phases and steps listed when the turn player passes priority.

In terms of passing priority, it goes like this:

When a player with priority has no more actions they want to or are able to perform, they pass priority. At this point, depending on which factors are true, things can go a few ways:

If the turn player has priority and the non-turn player hasn’t passed priority in this round of priority (because they haven’t received it yet), priority passes to the non-turn player.
If the player with priority performed any of the possible priority-based actions (e.g. casting a Summon, playing a Character etc.), priority passes to the other player.
If priority was passed from the other player and the player with priority performed no priority-based actions and the stack is not empty, the top item of the stack resolves.
If priority was passed from the other player and the player with priority performed no priority-based actions and the stack is empty, the game moves to the appropriate phase or step.

Couple notes here. First, I can’t completely ignore the stack when talking about priority, so if those parts are somewhat unclear to you, hopefully by the end of this article it will have all come together for you (and you can always come back to this part with the knowledge you’ll gain further down). Second, I mentioned this in my last article, but I’ll mention it again, there are things that happen when a player is to receive priority, which goes like this:

Perform a rules processes check.
If there are any triggered auto-abilities, place them on the stack.
Repeat steps 1 & 2 until there are no more rules processes to resolve nor auto-abilities to put on the stack).
The player who would receive priority gains it.

The details of which rules processes there are to be checked, and auto-abilities in general are better put in their own articles, so I won’t go into any further detail. I just want to make you aware that it isn’t as simple as a player just gaining priority and that’s it.

Before I bring in some simplified breakdowns of the important parts covered here, we first need to have a look at the rogue element. Priority in the End Phase. So, what can a player with priority do when they have priority in the End Phase? They can pass priority. That’s it. You might be asking yourself what the point of giving a player priority would be? Well, first, let’s be honest, in most real games, people aren’t taking the time to actually properly pass priority in the End Phase (or at all in some cases!). If something needs to happen in the End Phase, they deal with that, and otherwise it just becomes the next player’s turn. However, players not properly passing priority doesn’t suddenly make it still not a rather strange thing to have. So, if you’re wondering why, why, oh why, does the End Phase have priority at all, when you can’t do anything? Well, it’s firstly because of the process I mentioned above, the process that happens before a player is given priority. You see, the game is weird. Rules processes checks can happen without priority, although only in one specific instance, that being before an EX Burst resolves. However, auto-abilities being added to the stack is something that can’t happen unless a player is to gain priority. You’d think, like in the EX Burst example, if the game calls for something to happen, like putting triggered auto-abilities on the stack, they could just, put that in without the need of priority? Well, there is one last thing that the priority is needed for in this phase, to resolve the stack. In the four earlier points talking about passing priority, the third point mentions about the top item of the stack resolving when both players pass priority (while something is on the stack). I’ll get into more detail about this later, but essentially this can’t happen without priority existing (as I said very early on, the stack cannot function without priority). So yes, the priority feels pointless, but it ultimately does serve a purpose due to the way the game functions. *shrug*

Well, that does it for priority in general, all that’s left now is to turn it all into simplified breakdowns, for easy reference. First, let’s begin with when the turn and non-turn player have priority during a turn.

If you are the turn player and have priority, you can perform any of the following actions:

Activate an action or special ability.
Cast a Summon.
Play a Character (only during a Main Phase, while the stack is empty).
Play a Character via Back Attack (during the Main Phase regardless of whether or not the stack is empty, and during any step of the Attack Phase).
Pass priority (during the End Phase, this is the only action a player can take while they have priority).

If you are the non-turn player and have priority, you can perform any of the following actions:

Activate an action or special ability.
Cast a Summon.
Play a Character via Back Attack.
Pass priority (during the End Phase, this is the only action a player can take while they have priority).

Note: A player with priority can perform any of the listed actions possible, as long as conditions allow them to legally, and based on if they are the turn player, or the non-turn player, as many times as they want, for as long as they have priority. Unless otherwise stated, after each action performed, priority will return to the same player who performed the action.

Second, let’s breakdown (and recap from the last article) the different things that can happen when priority is passed.

When priority is passed:

If the turn player has priority and the non-turn player hasn’t received priority in this round of priority, the non-turn player receives priority.
If an action was performed by the player with priority, the other player gains priority.
If both players pass priority with no action performed in between, and the stack is empty, the game moves to the next step/phase, or, if it’s the End Phase, the next player’s turn. If the stack is not empty, resolve the top item of the stack, and after that, then the turn player gains priority.

The Stack

Any time a player either uses an action or special ability or casts a Summon, it goes on the stack. Likewise, triggered auto abilities are placed on the stack (before a player would gain priority as mentioned in the priority section). So, that’s what uses the stack (anything not listed does not use the stack), let’s now cover how the stack actually works, and then get into resolving the stack.

The general concept of how the stack works is fairly simple (although with the addition of all the other rules and mechanics it can be far less so in practice). The stack follows the LIFO (last in, first out) method. This means the top item (the last ability or Summon added) of the stack will be the first thing to resolve. After the top item of the stack resolves, then the next item at the top will always be the most recent ability or Summon added to the stack that hasn’t been resolved. As a basic example, let’s say that player A uses an action ability, adding it to the stack. Player B then adds a special ability, and then finally Player A casts a Summon, adding it to the stack. The stack now looks like this:

Summon
Special ability
Action ability

The Summon was added last, and is at the top, so will be the first thing to resolve. Now, just before we jump to how resolving the stack works, let me first quickly talk about where the stack is on the play area. Abilities naturally have no physical representation in the game, when you use an action ability it exists as text on the card and it going on the stack and resolving just exists in the minds of the players, but what about Summons? Those aren’t played to the field, they are cast directly onto the stack. So, where do you put a Summon on the field? Well, the truth is there isn’t a defined area where the stack is, but generally people will place cast Summons directly next to the Deck and/or Break Zone. Honestly, as long as it’s clear (as in not placed near, say, the Damage Zone in a way where it could be confused for damage taken), you’ll be fine.

Okay, you’ve got a stack formed, how the hell do you start resolving this thing? What’s the process? Well, to begin with, it’s time to refer back to priority. We kind of ignored it in the forming of the stack discussion because hopefully it wasn’t necessary to constantly bring up the fact you need priority to do x or y, however we can ignore it no longer! If both players pass priority with no action performed in between and the stack isn’t empty (let’s use the stack example we built earlier with the Summon, special ability and action ability on it going forward), then the top item of the stack resolves. Once the top item is resolved, if it’s a Summon, move it to the Break Zone (unless a replacement effect moves it somewhere else), and then the turn player gains priority (meaning the process before a player gains priority is performed as well, again, more on that another time). Now the turn player has priority, and things continue as they would. If the turn player (or non-turn player) adds anything to the stack, then the last thing added becomes the top item. If neither player wants to add to the stack, they just both pass, and then the top item of the stack resolves. This time it would be the special ability, going by our example. This process continues until the stack is empty and both players pass priority without performing an action, at which point the game will move to the next phase/step/turn. Don’t think you need to follow this process to the letter (trust me, it will be rare you find anyone that does), just be aware of your rights regarding priority as a player, and otherwise, if we use the example stack again, you can deal with resolving the Summon, special ability, and action ability back-to-back without the need to be saying you pass priority and waiting on your opponent to do the same. Short cutting is absolutely something I want to cover in another article, so all I’ll say (again) for now is know when you have the right as a player to do things, and don’t let your opponent cheat you out of those rights because they try and go too fast or shortcut through turns.

I don’t really think there is anything that needs a breakdown from the stack section, because it’s actually covered in the priority stages, but hopefully now you can see how it all fits together.

The End or Whatever I Call This Bit

Hopefully now you understand how priority, and the stack, each work (and work together), and too can experience the thrill of stopping your opponent when they go from playing Characters in the Main Phase straight into declaring an attack, and being like “during Attack Prep…” pew pew, priority, bitch! You just passed it, twice. Anyway, thanks for reading through this, I do hope it was helpful, and remember you can always email me if you have any questions (or find me on Discord, if you’re one of them modern youngsters). Before I go, I’m not sure when next month I’ll get the next Rules Processing out, but just so you know, I’ll be live and in person at the London Crystal Cup in March, along with my “amazing” t-shirt that is sure to burn your eyes out of your skull. I won’t be judging, I’ll be getting my ass handed to me on the field of battle, but feel free to say hi, or awkwardly stare at me from across the room, whatever you prefer. Later, skater.