MTG Strategy: Priority and When to Cast Your Spells

Magic is a really complex game, one where small edges can easily take over games. Most people get by just by knowing the basics of the rules, and using their best judgement and practice to navigate through unfamiliar situations.

This article offers a behind-the-scenes look at some of those rules you might’ve taken for granted. Without priority, instants work in a weird and ambiguous way and priority defines precisely what you can and can’t do with them. 

This can not only enhance your understanding of the game, but all sorts of tricks and neat plays are possible once you have this knowledge. The opposite is true too — if you’ve ever lost a game because Arena just wouldn’t let you make some sick play, priority may well be the reason!

We’ll also go over some examples of the optimal time to cast spells by exploiting priority and flesh out your knowledge of Magic’s turn structure.

What is Priority?

Priority represents the opportunities you have on each turn to take game actions. This includes casting spells, playing lands, activating abilities… really, the essence of playing the game. If you don’t have priority, you can’t do any of those things. Hence, you will have used priority a ton already in your games, however much experience you have.

Sounds simple enough, but priority can be very complicated until you understand the rules that govern it. If you pass priority one too many times, then you might find yourself unable to respond to something your opponent has done. You might already be in a new phase, or even in the next turn without intending so!

As a master of priority, there are all sorts of things you can do to game your opponents. You can wait for the precise best time to cast your spells, and give them ample opportunity to mess up or let the cat out the bag.

Information is key — leaving your opponents in the dark, while gathering as much intel as you can, will win you many games. By casting spells at the right time, you leave your opponents unable to make informed decisions, and you have maximum info to play around whatever they’re doing.

How Does Priority Work?

Priority creates windows of opportunity at most steps in a turn — that’s when you get to do things. The active player in a turn gets priority at every step before the nonactive player. Activeness here just refers to the player whose turn it is — they get the first crack at casting whatever they want. So you can’t play stuff in your opponent’s main phase before they play a creature — you have to wait for them to say go in paper, or press OK on Arena.

If both players pass priority on a certain phase, the game progresses to the next one immediately. If both players pass priority on an end step, the active player goes to cleanup (they discard down to seven cards and creatures heal themselves). Afterwards, it’s immediately the next turn. You never get to pass priority and then go “wait hold on I meant to cast something”, unless your opponent doesn’t do something themselves.

When the stack clears, that itself creates a window of priority, so you always have the opportunity to cast more spells — the game doesn’t progress until you both pass. Arena will often do this for you automatically, but you can set stops.

If you don’t have priority, you can’t do anything. This is why you can’t do things like cast Opt and then play a card between scrying 1 and drawing a card — the spell has to fully resolve before you get priority again.

Priority on MTG Arena

There are far too many little windows created to be useful on every turn, so people will shortcut through them. Arena simulates priority to a large extent, but it doesn’t take you through all your windows — you have to set your own using the little buttons at the bottom, if you need to do something at a specific time.

Priority and the Stack

Priority is what allows you to respond to your opponent casting spells and using abilities. As soon as most effects go on the stack, a window to respond is immediately created. The other player gains priority unless the caster holds priority i.e., announces that they want to take another game action in response to their own spell. This can be done by going into full control on Arena (holding the CTRL button).

Only some game actions create an effect that goes on the stack, and therefore give your opponents a window to respond. Your opponent can never respond to you:

• playing a land or;
• activating a mana ability (that’s an ability which adds mana to your pool)

Both of these are special actions, and can’t be responded to. If your opponent taps The Great Henge, they immediately gain 2 life and add GG to their mana pool, and there’s nothing you can do.

Say you’re trying to copy a spell using Doublecast. If you don’t hold control, then the original spell will resolve immediately if your opponent doesn’t respond to it (they usually won’t), so you’ll never get the chance to copy it. Doublecast is pretty useless if you don’t have some understanding of priority!

Clear Stack

Remember, you can only cast sorcery-speed spells (sorceries themselves and any other spell that’s not an instant and doesn’t have flash) while the stack is clear. You can’t play a creature, hold priority and then play another non-flash creature, nor can you play a creature, hold priority, and then play a land.

You can, however, play a creature then hold priority and activate another creature’s effect, or tap your lands for mana as you can do all of that at instant speed. (Tapping a land for mana is a mana ability, so it doesn’t even go on the stack.)

Deciding When to do Things

Use your mana at the last possible moment

If there’s no good reason to do something earlier, then you should almost always wait.

Spending your mana too early gives your opponents a lot of information and denies you the chance to change your mind and make a different play with more information. If you cast an instant on your main phase or on their end step, you didn’t lose anything — you still spent the same amount of mana.

As a common example, this means that if you don’t have a reason to cast a removal spell on your turn, then you should wait till the last possible moment on your opponent’s turn.

Here are some advantages of waiting:

• They might play a better removal target on their turn if you wait.
  
• They won’t know that one of their creatures will die, so they might make worse attacks. You could easily bait your opponent into making an attack that gives you lethal on the swing back, because they don’t know they’ll have one blocker less.
  
• If they were holding up some way to stop the removal spell, like a counterspell, then by passing the turn you force them to use mana on their turn and waste it on yours. If they use their mana on something else on the end of your turn, they won’t have the mana up to counter, so you get to resolve your spell guaranteed.

This doesn’t mean you should take a bunch of damage or waste mana by waiting, or give your opponent an opportunity to counter your removal spell / give their creature indestructible — those are good reasons to cast it now!

Just start asking yourself, “why am I doing this now?” and you’ll start to examine your decisions and improve over time.

Example A

Let’s say you’re trying to resolve a Murder against a Blue deck:

• If you cast it on one of your main phases, they might be able to use their mana more efficiently, and they have perfect information from then on. You want to do this when they don’t have mana ready — that way you get to resolve the spell guaranteed, before they untap their lands.
  
  If you’re killing a creature with relevant abilities, you might still want to deny them the opportunity to use those by casting Murder now.

• If you really want the Murder to resolve, then you cast it on their upkeep. This gives them the opportunity to cast things on your end step, in which case you resolve your spell safely. You lose the information of what they do on their turn and the potential for them to play a better target, but that doesn’t matter if you really need to kill the current target.
  
  This is also the last opportunity to cast things before your opponents draws a card for their turn. Afterwards, it’s more likely they can stop your Murder — they might’ve drawn a counterspell.
  
• Casting the Murder in combat stops them from attacking with the creature and gives you perfect information up till that point. Sometimes this is at the start of combat, so they don’t get some sort of attack trigger, like getting a token from Esika’s Chariot.

• Most of the time you cast things on their end step, so you have maximum information. Arena even places a permanent stop here rather than on your own end step.
  
  If you cast stuff in their end step, you’re saying it’s not that bad for you if they have an answer. For example, you might just want to tap them out so you’re more likely to resolve something on your turn.

Example B

Let’s say you’re trying to bait your opponent into double blocking or using a trick, before you blow them out with a removal spell. In that scenario, you want to exploit priority – you go to the declare attackers step of your turn, you send in the clowns, and then wait for your opponent to block before you do anything.

You pass priority on the blockers step, and then they choose whether to cast something or go straight to damage. That means that if the block is bad for them, you should always wait for them to cast something first.

If you have unconditional removal, and it’s their turn (so they’re using a trick on attacks), you can even wait for that trick to resolve in case they cast another — they have priority again since the stack clears.

If they’re multiblocking, and you want to save your creature, then you don’t want to pass priority — if they then pass back, we’re onto the next phase, and you missed your opportunity.

Sometimes if you’re sure they’re going to cast something, say if you know the contents of their hand, you can take the risk. If you cast the removal spell too early, they won’t also commit their trick, or their trick could be something like Beaming Defiance which will counter your removal. If you wait, then they might well try to outsize your attacker with the +2/+2, and then you can blow them out in response.

The Steps and Phases of Each Turn

In this section we’ll take a look at all steps and phases of a turn, and how priority works in them. Remember that priority is always active player (AP — the person whose turn it is), then non-active player (NAP).

There are five phases in each turn:

1. Beginning
2. Main Phase 1
3. Combat
4. Main Phase 2
5. End Phase

Phases are broken down further into into steps. Let’s take a look.

Beginning

Untap

• AP untaps all permanents they control.

• No priority. Nobody can take actions during this step.

Upkeep

• Most “each of your turns” effects activate.
  
  AP stacks their triggers first[1], then NAP stacks their triggers on top. This means NAP’s triggers resolve first.
  
• After that, both players get priority:
  
  Most of the time you won’t do anything on your own upkeep, unless you’re responding to something your opponent is doing. Sometimes you want to scry e.g., with Dragon’s Rage Channeler here to have better control over your draw step.
  
  Very useful phase for NAP, as shown in Example A.

Draw

• AP draws before either player gets priority.

• You don’t generally want to do things on your own draw step — just wait for main phase 1 and have more options.

• NAP: you can cast spells now if you want your opponent to have their drawn card now, but don’t want them to be able to cast it on their main phase. This usually means if you can affect their hand — e.g., if you’re discarding the card they just drew with Kolaghan’s Command.
  
  This is also a good time to use Field of Ruin against a deck with few basics. They might draw their last one (in which case they don’t get anything) and they can’t use their mana yet (except for instants).

Main 1

• Both players get priority.
  
• As AP, this is your first opportunity to cast sorcery-speed spells and play lands, with a second and final opportunity after combat. If you’re going to attack, you only want to play stuff that affects combat here — otherwise you give away free info, so they’re better prepared to block and such.
  
  Sometimes you can bluff by playing some stuff before combat, so they think you have less mana to work with and play into your instants.
  
• As NAP, you don’t generally want to cast spells that affect combat until the Begin Combat step. The only reason to cast spells now is if your opponent plays something with a beginning of combat trigger, like Legion Warboss — if you kill it now, they don’t get a Goblin.
  
  If you cast spells now, your opponent has the opportunity to play sorcery speed things or lands afterwards. Better to deny them that option.

Combat

Begin Combat

• You don’t want to cast spells or activate abilities now unless you’re responding to something, because it’s better to do so on your main 1.

• NAP usually only casts spells here if they want to stop the opponent getting an on attacks trigger. Otherwise, wait, so they have less info when they attack.

Attack Step

• AP chooses attackers at the start of this step. You finish choosing before anyone gets priority.

• AP doesn’t generally want to cast spells or activate abilities here. The reason to do so is if you forgot to do it before you declared attacks, since now you’ve committed your attackers and have less info. As always, you might respond to something the opponent does.

• NAP generally wants to wait until declare blocks to cast things, but this is the step in which you flash in a creature you intend to block with.

Blocks Step

• NAP choose blockers at the start of this step. You finish choosing before anyone gets priority.

• If the opponent declares multiple blockers for any of your creatures, AP needs to immediately choose the order of creatures you’re dealing damage to.

• After that, this is both players’ last chance to cast tricks and such. AP needs to cast their trick first — if both players pass priority, then damage happens immediately.

• NAP mostly wants to wait till they’ve blocked to cast pump spells, like Lunar Frenzy. If you cast them in attacks, your opponent might remove your creature, and then you’ll need a new blocker/ will end up taking damage you would’ve avoided by blocking first.
  
  To play around counterspells, cast the pump spell in attacks. If you block first and then your opponent counters your pump spell, you’re committed to blocking and will likely lose your creature. See Example B.

First strike damage step

Only happens if there’s a creature with first strike or double strike participating in combat (attacking or blocking). Otherwise, you skip it.

• First strike damage happens at the start of this step. Afterwards, priority happens as normal, so you can let first strike damage happen then cast a burn spell to finish off a creature. This means it won’t hit the first strike creature back.

• Double strike creatures do their first instance of damage here.

Regular damage step

• All other damage happens at the start of this step. All damage is dealt at the same time — creatures that have sustained lethal damage are put into the graveyard at the same moment as the defending player is dealt combat damage.

• Neither player gets priority until after damage has happened.

• Double strike creatures do their second instance of damage.

End of combat step

• Both players get priority. This is the last step in which a creature is considered attacking or blocking.
  
  Sometimes you want to cast a spell like Blessed Alliance that says “Target player sacrifices an attacking creature” in this step. Other smaller creatures may have already died, so they have to sacrifice a better one.

Main Phase 2

• AP has their final opportunity to cast sorcery-speed spells and play lands this turn.
  
  This is generally where you want to take most of your game actions — combat has already happened, so you have the information from that, and you’re not giving info away.

• NAP doesn’t want to cast spells here, unless something has an end of turn trigger you want to deny.

End Step

• Any end step triggers go on the stack before anyone gets priority.

• AP would rather just cast stuff in main phase 2 usually. However, this is an important time to respond to things, since it’s the phase of your turn the opponent will use the most.

• NAP’s last and best chance to use mana before they untap. See Example A.

Cleanup Step

• No priority. The active player discards down to 7 cards. All end of turn or “this turn” effects end in this step, and all damage marked on creatures is removed.

• The main way to get priority in this step is to respond to discard triggers from discarding to hand size. If there’s a “whenever you discard a card” effect, that will generate triggers that you can respond to. Otherwise, it’s pretty much impossible.

Ordering Triggered Abilities

Arena does this automatically, but you can choose the order in which your triggers resolve. If you put a trigger on the stack first, it will resolve last.

Sometimes having control over this can be very useful, e.g., if you choose to sacrifice a creature after you generate a token, so you don’t have to get rid of something better.

Conclusion

Thanks for reading! Follow me at @Mulldrifter06 to check out my other work.

For more Magic articles, check out the following:

• Midnight Hunt Draft Tier List (my first article for the site!)
• MTG Deck Building Guide
• 6 Tips for Sideboarding in Traditional Draft