Step By Step: Layers
Layers have gained a reputation among players and judges as as being overly complicated and difficult to understand. This is a shame, as the core layers system is actually pretty elegant and conceptually simple.
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The way to break out of this self-fulfilling prophecy is to, well, just learn how layers works. I promise it's not actually that complicated. If after reading this article you're still confused about any aspect of layers, that means I've failed to explain it well enough. Please let me know what you're confused about so that I can find a different/better way to explain it.
What problem is the layer system solving?
Abilities of cards in Magic fall into two general categories: actions and statements.
Cards like Murder, Lightning Bolt, and Healing Salve all give a player an instruction to do something. The player does that thing, and then the game moves on. Other abilities don't tell any player to do anything; they just make a true statement about the game. Bellowing Tanglewurm, Alpha Authority, and Giant Growth are all like this; they don't have a player take any action, but rather they change something about the rules of the game. Normally there isn't any rule that green creatures have intimidate, but when you control Bellowing Tanglewurm, there is.
Magic calls the first type of effect a "one-shot effect", and the second type of effect a "continuous effect", for obvious reasons.
The simplest way for a conflict to arise is when one effect says that something is true, and another effect is in denial and says that that can't possibly be true. For example, Aggressive Mammoth says that creatures have trample, while Archetype of Aggression says that they can't have trample; these two things can't both be true at the same time! These conflicts are handled in a very simple way: The "can't" effect always wins. No layers system is needed for these.
But there are also some more subtle ways for conflicts to arise.
- Two effects can try to do different mutually-exclusive things, like one that says "creatures are green" and another that says "creatures are blue".
In Magic, effects like that always remove other colors unless they specifically say they don't, so "are green" actually means "are green and no other colors".
- One ability can do something, and another ability says that the first ability doesn't exist. "Creatures are green" (on a creature) and "creatures have no abilities" technically can both be true at the same time, but the second ability is obviously supposed to make the first one not be true.
- Two abilities can do things conditionally, where each condition is affected by the other ability. "Green creatures have intimidate" and "creatures with intimidate are green". If you play a creature that's normally neither green nor particularly intimidating, does it bootstrap itself into being both? If not, what happens if some other effect turns it green temporarily, and then that effect goes away; does it now stay green forever through this loop?
- You could also have a negative loop with no stable configuration. "Green creatures are elves", "elves are 4/4s", and "4/4 creatures are red".
- And effects can even conflict with themselves. If a creature has the ability "creatures have no abilities", what happens? Or how about something like "green creatures are blue"? If they're blue, then they're not green, so this effect doesn't apply, making them not blue, so it does apply...
These sorts of contradictions are inevitable in any powerful-enough system of logic; just like saying "this sentence is false".
Clearly, there needs to be some system in place for Magic to handle these cases.
How do they solve it?
The solution they used is to have each effect conceptually apply only once, in a specific order. This way there can't be any infinite loops at all, and no way of handling those is needed.
To apply this system to the statement "this sentence is false", we start out by assuming all statements are true. We apply this statement and determine that it's false. Now we're done. We don't go back and check it again; we just end with that statement being false. Pretty straightforward really.
So if there's a card that says "this card loses all abilities", we apply that ability and the card loses it. Then we're done. The game doesn't go back, see that nothing is making it lose that ability, and give it back; it just leaves it at that.
The same is the case for multiple abilities. If you have one effect that says "creatures are green" and another that says "creatures are blue", the game simply applies one first, let's say the green one, and then the second one, making everything blue. The end result is that all creatures are blue.
An important piece of nuance here is that this is only a conceptual order, not a temporal one. In the former situation where you have both cards on the battlefield, there is no point in the progression of the game where creatures are green. If you have a spell that says "destroy target green creature" or a trigger that triggers whenever a creature is green, you never have a chance to cast that spell, and the trigger never triggers.
A nice analogy is that of putting colored filters in front of a movie projector. The order in which you place the filters might matter; the final picture on the screen could look different if you put the green filter in front of the blue one vs. blue in front of green.
Ok, but what order?
Knowing that continuous effects are applied in a specific order, one-at-a-time, is helpful, but we also need to know what order. This is the part of the layers system that feels somewhat arbitrary, and can be hard to remember.
The ordering of effects consists of two separate systems: Layers and timestamps.
The first system, layers, involves dividing all effects into a few separate categories depending on what kind of effect they are. These categories, called "layers", are applied in a specific order, such that effects of one type always come before effects of another type.
The second system, timestamps, exists to handle the situation where there are still conflicts after separating out effects into the predefined categories. It defines an internal ordering for effects in the same layer.
We'll take these one at a time.
The layers are as follows:
- Copy effects, along with some other things. Any effect that says that one thing is a copy of another, such as Clone, Mirrorweave, or Metamorphic Alteration.
Note that tokens created as a copy of something else, such as those of Rite of Replication, do not fall under this. That's not a copy effect, that's just defining the original "printed text" of the token.This layer also includes some things that aren't copy effects, such as mutate, cards being face down due to morph and manifest, and things like Primal Clay that pick a P/T as they enter or turn face up.
- Control-changing effects. Things like Control Magic, Act of Treason, or Blatant Thievery that give a player control of some object that another player previously controlled.
Note that effects that put something onto the battlefield or stack under a certain player's control, such as Bribery and Reanimate, do not fall under this. Those aren't control-changing effects, those just define the permanent's default controller in the first place.
- Text-changing effects. This covers a very narrow range of cards that specifically say "change the text", like New Blood and Mind Bend, along with some keywords that do this like overload, cleave, and splice. And there are a few other weirdo cards that apply here too, such as Volrath's Shapeshifter, Exchange of Words, and Spy Kit.
- Type-changing effects. This includes changing anything on the type line, including supertypes, types, and/or subtypes. Blood Moon, Rootpath Purifier, Xenograft, etc.
- Color-changing effects. Painter's Servant, Ghostfire, etc.
- Ability-modifying effects and counters. Anything that grants a card an ability (Aggressive Mammoth, Ferocious Tigorilla), removes an ability (Dress Down, Glittering Lion), or says that an object can't have an ability (Archetype of Aggression).
- Power/toughness modifying effects and counters.
So any time you have two effects that apply in different layers, they apply in this order. "All lands are creatures" (type change, layer 4) applies before "all creatures are green" (color change, layer 5), meaning all lands will be green, exactly as you'd expect.
Unfortunately it's not quite this simple. There are several "secret layers
First off, there are the original printed characteristics of the card. This isn't an effect, it's just what you start with before applying any effects. It can be convenient to think of this as "layer 0". This includes taking into account the alternative characteristics of a double-faced card that's on its back face or melded, those of a prototyped card, and those of flipped flip cards.
Next up we have effects that don't modify the characteristics or controller of any object, and therefore don't fall into these layers. When does Platinum Emperion apply? How about Leyline of Sanctity? These apply after all other effects; first anything that affect's a player's abilities, like Seht's Tiger, and then everything that just affects the game rules, like Meddling Mage. We can think of these as layers 8 and 9.
Ok, so ten layers in total, right? Eh, not quite. We still have all the sublayers.
Some layers are further subdivided. These sublayers function exactly like additional layers; calling them "sublayers" is just an aesthetic/organizational difference.
Within layer 1, we first apply all copiable effects. (Copy effects, mutate, and "As enters" or "as turned face up" abilities that set P/T.) Then after that, in a separate sublayer, we apply any characteristics they have from being face down.
And in layer 7, there are 4 sublayers:
- Effects from characteristic-defining abilities that affect power/toughness. (Tarmogoyf, Sutured Ghoul)
- Effects that set power/toughness to a specific value. (Harmonious Archon, Turn to Frog, Duplicant)
- Effects and counters that provide an additive bonus to power/toughness. (Giant Growth, Phyrexian Ingester, Dismember, Burst of Strength)
- Effects that switch power and toughness. (Twisted Image)
Next up we have the fact that characteristic-defining abilities are applied first in all the other layers too. (Well, they can only exist in layers 4 and 5.) For whatever reason the CR doesn't define these as sublayers, but they function identically. You can think of layers 4 and 5 as having their own sublayers that are just "sublayer 1: CDAs" and "sublayer 2: Not CDAs".
Lastly, we have something that isn't directly relevant to layers at all, but still happens as a part of the system: determining an object's copiable values. Knowing that Clone takes into account other copy effects, mutate, face-down-ness, transformedness, and that sort of stuff, but not Mind Bend, Turn to Frog, +1/+1 counters, etc. The way the rules handle this is to say that copiable values are all determined after layer 1 and before layer 2.
Oh, and of course we also have the fact that a player's devotion to a color is determined after text-changing effects are applied, but before type-changing effects are, allowing Heliod, God of the Sun to work properly with Volrath's Shapeshifter. (This is sometimes called layer 3.5.)
All of these additional details seem complicated, and they are hard to remember, but they're not complicated on a conceptual level; they all work exactly the same as additional layers. We can rephrase all of this, with no functional difference, as the game simply having 19 layers and no sublayers or extra stuff:
- The object's printed characteristics.
- Any alternative characteristics the object may have due to some state it's in, like being transformed or prototyped.
- Copiable effects.
- Characteristics that come from being face down.
- Calculate copiable values.
- Control-changing effects.
- Text-changing effects.
- Calculate devotion.
- Effects from type-changing characteristic-defining abilities.
- Type-changing effects that do not come from characteristic-defining abilities.
- Effects from color-changing characteristic-defining abilities.
- Color-changing effects that do not come from characteristic-defining abilities.
- Ability-changing effects and counters.
- Power/toughness setting effects that come from characteristic-defining abilities.
- Effects that set power/toughness to a specific value.
- Effects and counters that provide an additive bonus to power/toughness.
- Effects that switch power and toughness.
- Effects that add or remove abilities from players.
- All other effects.
You may notice that layers were originally advertised as being about the interaction of continuous effects, but grew into an unholy mishmash of continuous effects, counters, statuses, unnamed "card states that cause alternative characteristics to be used", and the definitions of various game values such as an object's copiable values and your devotion to a color. This is true. Layers consumes all.
Luckily, the majority of that stuff almost never comes up. The important things are just knowing the order of the basic 7 layers, and the power/toughness sublayers.
Remembering the order
Different methods of remembering the order of the layers work better for different people. I'll present all the ones I'm aware of here, and hopefully one of them works for you. If something else worked for you that you don't see listed here, please mention it in a comment and I'll add it in.
First up is my personal favorite: Figure it out for yourself based on the game design principle of "cards should do what they say". Copy effects have to come before control-changing effects, because otherwise using Copy Enchantment to copy Control Magic wouldn't work properly. Control-changing effects have to come before text-changing effects because otherwise Volrath's Shapeshifter would have the text of the top card of your opponent's graveyard if you steal it with Act of Treason. Text-changing effects need to come before type-changing effects because you could use Mind Bend to make Blood Moon turn things into Forests instead of Mountains, and that should work as expected. Type-changing effects need to come before color-changing effects because if you animate a land, Darkest Hour should make it black. Color-changing effects need to come before ability-changing effects because Roughshod Mentor should take into account anything that becomes green or stops being green. And ability-changing effects need to come before power/toughness changing effects because making Benalish Marshal lose its abilities should make it stop buffing your creatures.
That system isn't perfect, because there are some unintuitive results of the layers system. Making Painter's Servant or Magus of the Moon lose its abilities doesn't do anything, because those abilities have already applied in an earlier layer; this is quite unintuitive and would not be the result of a well-designed rule system. But as long as you can remember that ability-changing effects come second-to-last, after type and color changing effects, you can derive the rest from there from first principles.
If that doesn't work for you, try the acronym: CCTTCAP. It's a terrible acronym. It means nothing. Pronounce it out loud: "K-K-T-T-cap". It sounds like you're having a seizure. It's so bad that after you do it a few times its badness will be seared into your permanent memory.
Are you a sane human who wants to avoid summoning the eldritch beings that might appear if you say that too many times in a row? Alright, try one of the mnemonics:
- "Chandra couldn't tell teferi could alter planes"
- "Cici's two-topping cheese anchovies pizza"
- "Cops can tax tips collected at parties"
- "Sissy, titty, cap!"
Don't blame me, I found this on the Magic Judge subreddit.
- "Cults and cabals tend to take converts away from people"
- "The 3 things judges do: commander, clear table trash, complain about players"
This is my personal favorite, because it's completely true.
- "Cool cats take the catnip and purr"
- Or just make your own here. The first one I got was "curly cheerleaders thrashed Tarzan concerning Aquaman provocatively". Your results may vary.
Note that with all of those you'll still have to remember which "C" is which and which "T" is which, so they're not amazing. Maybe a mnemonic that uses full words would be better, but I don't have any good ones to share.
What worked for me was the completely unclever approach: Just repeat "copy control text type color abilities power" to yourself over and over until you remembered it.
An alternative is to use your visual memory instead of your conceptual memory. Humans are much better at remembering images and diagrams than strings of text
It doesn't include the first two layers, but then the other 5 have a clear correspondence to a certain part of the card, and you can remember this pattern of directions.
If all else fails, just sing the layers song.
When layers aren't enough
All this so far has only told us how to apply two effects that exist in different layers. (Or sublayers.) What do we do when they're in the same layer?
We go by the order they "happened" in, for a specific definition of "happened".
Every effect is given a "timestamp".For an effect generated by the resolution of a spell or ability, its timestamp is the time at which it resolved.
For an effect generated by a static ability of a permanent, its timestamp is the same as the timestamp of the permanent. This is usually the time at which the permanent entered the battlefield, but some other things can cause it to update its timestamp, like being turned face up, or an equipment being attached to a creature. The full list is boring and you can just go read it in 613.7.
The relevant thing is that they're applied in what is, most of the time, the obvious intuitive order. If you play Shifting Sky on green followed by Shifting Sky on blue, they're applied in that order, and the green gets overwriten to blue.
L2 judge Ryan Sears has a nice representation of how layers interact with timestamps: Imagine it being two-dimensional! Put each effect in its appropriate square, and then you just apply the effects like you would reading the text on a page; start in the top left and go to the right, then go down to the next line and repeat. Etc.
Bonus points if you can figure out the answer based on only the card arts.
So timestamps are the "tiebreaker". When effects are of different kinds and therefore in different layers, you just apply them in layer order. When there's a "tie" because they're both in the same layer, you use their timestamp to determine their order within that layer.
But wait a minute; isn't there a problem here? If I play Kwende, Pride of Femeref and then cast Battlefield Promotion on my Glory Seeker, we'll apply Kwende first, doing nothing, and then apply Battlefield Promotion afterwards, giving it first strike only, and not double strike.
That would be pretty unintuitive, and luckily the rulebook has us covered. When two effects are in the same layer and one "cares" about the other, there's a system called "dependency" that can override timestamps and change their order into the order that actually makes sense. Formalizing this system is a bit complicated, so I put the details in Step By Step: Dependency. The TLDR is "If two effects apply in the same layer and it seems obvious to everyone that one of them should apply before the other, it probably does."
Quick hits and common misconceptions
Some things that frequently trip up judges and I want to call out specifically:
Some effects do multiple things, like "Creatures you control get +1/+1 and are red". For effects like this that seem as though they should apply in multiple layers... they do! The game applies each part in its appropriate layer, not all at once. (Note that as soon as the first part is applied, the game has now "committed" to applying this effect to that set of objects, and removing the ability later on in layer 6 won't cause the rest of it to stop applying, nor will other characteristic changes change what it applies to.)
Timestamps do not determine "which effect applies". They only determine the order in which effects apply. All effects still apply regardless! (Unless one of the abilities is actually being removed by another.) For example, I frequently hear people say things like "If you have Blood Moon and Dryad of the Ilysian Grove, the one that most recently entered the battlefield is the one that applies." That is not true! They both apply, and timestamps just determine which one applies first. This is why, if Dryad of the Ilysian Grove entered first followed by Blood Moon, basic lands will still have all basic land types. If the Dryad didn't apply at all, that would not be the case. It's just that after the Dryad applies, the Blood Moon then applies, and turns all nonbasic lands into Mountains.
Some characteristics cause other characteristics to change. Mana cost can cause color to change, text can cause abilities to change, and type and subtype can also cause abilities to change. (Planeswalkers and battles have intrinsic ETB abilities to enter with counters, and anything with a basic land subtype has an intrinsic mana ability and potentially loses its other abilities.) These changes all happen at the same time as the original change, not in a later layer. If your Bear Cub becomes a copy of Glory Seeker, it becomes white in layer 1, not layer 5.
Effects never get "un-done". Ever. The layers progress only forwards, not backwards. There is never a situation where applying some effect will cause the game to go back and change something about an earlier effect. What can happen is the one effect affects the same object as a previous effect, and overwrites it. When Blood Moon applies after Dryad of the Ilysian Grove, that is not Blood Moon "undoing" Dryad (which is why basics retain all types), that's Blood Moon doing something else after Dryad has already done its thing. This is true even if an ability that already applied is later removed. If you control Dress Down and Painter's Servant, Painter's Servant makes things a color in layer 5, and then it loses that ability in layer 6, but we don't go back and undo the color change in layer 5.
Conditional effects don't get a new timestamp when they "turn on". If you control Aeronaut Tinkerer enchanted by Grounded and then play an artifact, it doesn't gain flying; the Aeronaut's timestamp is still earlier than Grounded's, so Aeronaut applies first and then it loses flying afterwards.
Normally at the end of my rules articles I include some practice questions. But this article is already long enough, and layers questions are already very common on the internet. You really can't be a Magic player online and not run into them.
Someone just unironically asked me what happens here. pic.twitter.com/vL22N0jn8j— Isaac King 🔍 (@IsaacKing314) October 26, 2022
Seriously though, do practice. Rote memorization of this article won't help you at all if you can't apply these steps yourself in a new situation that you haven't seen before.
Petr Hudeček's layers sandbox is an amazing place to get this practice. It lets you generate custom cards with various effects that depend on other effects, and see what the results are. Play around with it and see how results change as the abilities and timestamps change.
RulesGuru also has a lot of layers questions. Just select the "layers" tag in the sidebar.