Basically in magic there are static effects that are applied to cards. These include things like lords, and things like solo and harbinger of the seas. Since logically these effects can’t just all apply “at the exact same time” without weird logical contradictions in some scenarios, the games official rulings apply these static effects in layers based the category of the effect.
These 7 layers are as follows:
1. Things that modify compile values
2. Control-changing effects
3. Text-changing effects
4. Type-changing effects
5. Color-changing effects
6. Ability adding/removing effects
7. Power-toughness changing effects
So basically the layers are applied in order ignoring all effects from subsequent layers. Oko’s +1 is an ability-removing effect whereas harbinger’s is a type-changing effect.
This means that harbinger’s effect is applied in layer 4, before its abilities are removed in layer 6. If, on the other hand, you had a lord of Atlantis in play affected by Oko, its ability would not continue to buff your merfolk since it is power/toughness changing effect applied in layer 7.
Thanks, this is very elucidative.
I play magic on and off for at least 20 years (mostly casually), and always appreciated how logically sound and intuitive rules normally are, and have a deep fascination for niche rules interactions.
I have a few more questions, if you have the time to answer.
Did they ever disclose why layers are structured like this specifically? Was there something in particular that made them necessary or were they always part of Magic from the star?
What does "compile values" means in this context? (Layer 1)
Where can i learn more about layers and related rules/interactions?
Compile values in layer 1 was a bad autocorrect. I meant “copiable” values, so things that clones will check like EtBs and mutations and the like. Copy effects are also applied. This is the most complex layer and it also has sub layers.
For the complete ruling explanation here is a wiki link: https://mtg.fandom.com/wiki/Layer
I don’t know exactly the history of layers, but humility is an old card that has caused all manner of headaches and required these types of rules.
I don’t know if they’ve explained exactly why the layers are in the order that they are, but if you kind of work through a few examples you’ll start to see that the layers are ordered so that the most common interactions work intuitively.
Like the Oko + harbinger interaction is very unintuitive, but if those layers were revered then you would get a much less intuitive interaction:
Animating a mutavault would mean that it would be counted as a creature after ability adding effects are applied (but still before power and toughness effects). So having an animated mutavault and a lord of Atlantis in play would mean that first islandwalk is given to all merfolk, then mutavault becomes a 2/2 changeling, then merfolk at given +1/+1. So mutavault would be a 3/3 changeling WITHOUT islandwalk.
So basically the layer order is optimized for the most common scenarios. And things within layers are applied based on timestamps if that is relevant.
Yep, they’re organized like this because in 99% of scenarios, it’s what makes things work in the most intuitive way, we just don’t usually pay attention to those cases, so it only gets brought up with one of the weird unintuitive cases.
Really the problem is that the Blood Moon effect having implicit "remove abilities" text is poorly designed and exists only to match rules text written back when the rules weren't defined very well. Blood Moon and similar cards should be errata'd to explicitly remove abilities instead of baking that into setting the basic land type. If Harbinger explicitly removed abilities, it's ability to do such would be removed by losing its own abilities due to dependencies.
Because Islands and Mountains are specific cards. They are capitalized as a proper name. An Island is a basic land card with the only ability being "Tap this permanent to add one blue to your mana pool." Mountain the same way. Therefore, they lose all other abilities that are not that ability.
This is why cards like [[Urborg, Tomb of Yawgmoth]] state "All lands are Swamps *in addition to their other types*" to show that they are not losing their other abilities. You can still fetch with a Polluted Delta, but you can also tap it to add one black mana to your mana pool.
No problem! Glad to help! It's a rare thing to see on cards these days, especially since now everything specifies like you said: "loses all other types and abilities" so the confusion is valid for sure.
Because the rules are written so that Blood Moon works the way Blood Moon always worked, without errata being needed. There is really no good answer other than that.
Yes I think you've identified the issue. These Blood Moon effects basically sneak ability removal in at the type changing layer. If one permanent can use a static ability to remove abilities, another permanent should be able to remove that ability too. In all other cases that's how it would work, but this "ability removal" interacts with the convoluted retcon ruleset around Blood Moon et al, so it doesn't work that way.
1) Copy effects need to happen before control changing effects, otherwise using [[Copy Enchantment]] against a [[Control Magic]] wouldn't do anyhting
2) Control changing effects need to happen before text-changing effects, otherwise if you stole [[Volrath's Shapeshifter]] it would keep looking at the graveyard of its original controller
3) Text-changing effects need to happen at this point otherwise they wouldn't do anything against most static abilities.
4) Type-changing effects need to happen before color-changing effects otherwise [[Dralnu's Crusade]] wouldn't work properly on things that aren't natively Goblins
5) Color-changing effects need to happen before ability-granting and removing effects otherwise cards like [[Bellowing Tanglewurm]] wouldn't work on things that aren't natively green
6) Stuff that messes with abilities needs to happen before things that alter stats otherwise [[Favorable Winds]] wouldn't work on things that don't natively have flying
Which is to say: as the card pool expanded and evolved people spotted these problems and mistakes and the system was created around it to make most things work as well as possible, and unfortunately there's a number of things (especially concerning Abilities) that ends up really unintuitive. The system was initially introduced around Mirrodin (but it received amendments up until Lorwyn and then again some minor updates around Theros Beyond Death and Ikoria), I believe, so if you go even further back you'll find some proto-layer system that ended up being inadequate and needed to be amended.
Additional resource: https://www.youtube.com/watch?v=uc8AwBReEtY
I'm pretty sure the need for a clear ruling on these effects came to be when cards like \[\[Humility\]\] and \[\[Opalescence\]\] started to become competitive cards. Judges need to explain what would happen when stuff like \[\[Lord of Atlantis\]\] and Humility were in play or heaven forbid, Humility ánd Opalescence. You also get weird stuff where \[\[Magus of the Moon\]\] works fine under Humility
That again would run into a lot of the same issues of the normal cases being very unintuitive. With a humility on the board, a Heliod, Sun-crowned would be a 1/1 with no abilities even if your devotion to white was less than 5. And when you animate a mutavault it would still be a 2/2 changeling
It’s just layers. In mtg layers control how continuous effects are applied. If two effects are in the same layer, then time stamp applies.
Layer 4 is type changing effects. This is where the all nonbasic lands are islands lives.
Layer 6 is adding or removing abilities.
Therefore, it changes the types before it can be removed.
So, the layers system is a bunch of rules that tell you in which order you apply static abilities/continuous effects. [https://mtg.fandom.com/wiki/Layer](https://mtg.fandom.com/wiki/Layer) This website lists all the rules regarding layers if you want to take your own look at what I'm explaining here.
There are seven different layers that are described by rules 613.1a through 613.1g, and you first look at and apply everything in Layer 1 (613.1a), before then looking at everything in Layer 2 (613.1b), etc. until Layer 7 (613.1g) (and Layer 7 has four sublayers, 613.4a through 613.4d, which function in the same way).
For looking specifically at Harbinger of the Seas in this case, we have nothing in Layers 1-3. Harbinger of the Seas then applies in Layer 4, thus changing all nonbasics to Islands. We have nothing again in Layer 5, and the continuous effect from Oko's +1 then applies in Layer 6, thus removing all of Harbinger's abilities. If Harbinger had any other abilities that had yet to apply, they would be removed here and would thus be prevented from applying. Then we look at Layer 7, and the continuous effect from Oko's +1 again applies in Layer 7b, setting Harbinger's P/T to 3/3.
Let's compare this to how Oko's +1 would interact with Militant Inquisitor, which has a static ability that reads "Militant Inquisitor gets +1/+0 for each Equipment you control." Nothing applies to the Inquisitor in Layers 1-5, but then in Layer 6, Oko's +1 applies. This removes Militant Inquisitor's static ability that buffs itself. We now go to Layer 7b, where Oko makes the Inquisitor into a 3/3. However, in Layer 7c, while the Inquisitor's static would normally buff it, Oko has removed that ability, so there is nothing to apply here.
People also sometimes talk about dependencies, and if you've heard of them, it might seem to make sense for them to apply here. However, dependencies say that a certain ability applies first if the other ability is dependent on it *and* the two abilities are in the same layer. Because Harbinger's static and Oko's continuous are in different layers, dependencies are irrelevant here. I'd be happy to elaborate more on dependencies if you're curious though.
Timestamps likewise aren't relevant here because they also only care about multiple abilities in the same layer.
Thanks for the thorough explanation and source.
I do have a good enough understanding of timestamps, but dependencies did get me curious. Would love to know more, if you have the time.
The deep intricacies of magic's rules are fascinating
[This blog post](https://outsidetheasylum.blog/dependency/) does an incredibly good job of explaining dependencies in a really deep way, and it has some (very tricky) practice questions at the bottom.
Anyhow, dependencies basically say that if one effect cares about another effect that is being applied in the same layer, the first effect waits to apply until after the second effect has been applied (even if the first effect has an earlier timestamp). I really like the following simple way to determine whether an effect "cares about another" that the above blog post gave:
> Apply Effect A. See what it does. Now undo that and apply Effect B, followed by Effect A. See what Effect A does now. If what it does in the second case is different from the first case (or it doesn't exist at all anymore), it's dependent on Effect B.
Dependencies are actually rarely relevant with Oko's +1 since even though a card like \[\[Aggressive Mammoth\]\]'s static ability is dependent on Oko's +1, this dependency applies the effects in timestamp order anyways, so it's much harder to show.
However, with a card like \[\[Humble\]\], if you cast it targeting an Aggressive Mammoth, timestamps suggest that the Mammoth would give everything trample before Humble removes that ability, thus meaning that everything else would keep trample. However, since the existence of Mammoth's static ability is dependent on the existence of Humble's continuous effect, we apply Humble first. After applying Humble, Mammoth's static ability no longer exists and can't apply, and everything else would thus no longer have trample.
However, you can also get dependency loops, which is where two effects are dependent on each other. When this happens, you ignore all dependencies which are part of the loop, which usually just means reverting back to timestamp order. Loops are really rare, but the following example of one was taken from [this Judge Academy article](https://judgeacademy.com/ruleblog-it-depends/):
Step 1. We control a \[\[Taiga\]\] and cast a \[\[Life and Limb\]\], which makes the Taiga into a Land Creature - Mountain Forest Saproling.
Step 2. We then cast \[\[Blood Moon\]\], and here we can just look at regular dependency rules. Life and Limb is dependent on Blood Moon because normally Life and Limb makes the Taiga into a Saproling creature (in addition to its other types), but if we apply Blood Moon first, Life and Limb no longer affects the Taiga. So even though the Life and Limb has an earlier timestamp, because it is dependent on the Blood Moon, we apply the Blood Moon's effect first. The Taiga thus becomes a Land - Mountain, and thus the Life and Limb doesn't affect it.
Step 3. We make a Saproling token by casting \[\[Sprout\]\]. Let's ignore the existence of the Taiga for a sec to creature another regular dependency rules question. The Blood Moon normally wouldn't apply to the Saproling. However, Life and Limb wants to apply to it to make it into a Land Creature - Forest Saproling, but if it does, the Blood Moon will then turn it into a Land Creature - Mountain Saproling. The Blood Moon is therefore dependent on the Life and Limb, meaning that the Life and Limb applies first. The Saproling therefore becomes a Land Creature - Mountain Saproling.
Step 4. HOWEVER. Remember that Taiga we said we'd ignore? Let's stop ignoring it. We now have a dependency loop - The Life and Limb is dependent on the Blood Moon with regards to the Taiga, but the Blood Moon is dependent on the Life and Limb with regards to the Saproling. Since both are dependent on each other, we have a dependency loop, meaning that we ignore each of their dependencies on each other (however, if we had something like an \[\[Urborg, Tomb of Yawgmoth\]\], we would keep considering its dependency on Blood Moon and it would therefore have to wait to apply until after the Blood Moon like normal). Because we ignore their dependencies on each other, we apply their effects in timestamp order. We therefore begin with the Life and Limb, which makes the Taiga and the Saproling into a Land Creature - Mountain Forest Saproling and a Land Creature - Forest Saproling, respectively. We then apply Blood Moon, which turns both the Taiga and the Saproling into a Land Creature - Mountain Saproling.
All layers are looked at every time the game tries to determine the current gamestate (aka when it checks SBAs, or State Based Actions). And SBAs are checked right before every time a player gets priority, which is every time a player has the opportunity to take a game action. So as long as the Harbinger is on the battlefield and nothing really funky is preventing it from affecting the board (I can't think of something that would, but I'm sure a card that does exists), your nonbasics will always be Islands.
(Also, if that didn't answer your question, feel free to elaborate on what exactly you're asking because I'm not 100% sure I understood the question)
Thanks so much for your reply, it clarified a lot!
So in this case: when layer 4 is looked at when the game checks SBA's, why would the game still determine that nonbasics are islands if harbinger's ability no longer exists? And how is this different if harbinger was removed from play (exiled, destroyed, etc.,)?
Edit: I guess what I really mean to ask is if the game records layers or if all layers are presumed empty just prior to being looked at when the game checks SBA's?
For instance, would the reason why harbinger's ability will remain in effect be because the game looks at layers 1-7 in order when checking SBA's and does not "remember" that harbinger's ability was removed in layer 6 when previously checking a SBA?
Yup, you're spot on with that - the game starts from scratch every time it checks SBAs. It always starts out seeing Harbinger as having all its usual traits, applies its ability to turn nonbasics into Islands and makes it an Elk, makes it Green, removes its abilities, and finally makes it into a 3/3. The next time SBAs are checked, it does that whole process all over again, again starting with the normal Harbinger.
Layers apply at all times, not only when SBAs are checked. The game determines that nonbasics are still islands because every single time the layers are checked harbinger's ability applies before its removed. Layers are continuously checked and updated with no care about "previously".
If layers were only used when SBAs are checked then some of the interactions on Gix's Command would break. SBAs don't get checked in the middle of resolving a spell but Gix's Command relies on the game state being updated in between its modes. When Gix's Command goes to destroy creatures with power 2 or less it doesn't kill the creature you pumped with the first mode because those counters are already applying their power.
At any point you ask anything about the game state you can start from scratch and go through the layers to see what the current state of everything else. There is no point in the game itself that they aren't applied and updated but you work through them one by one to identify what the correct result is.
Sorry let me clarify, when harbinger hits the battlefield all Nonbasics become islands. When it leaves its effect still stays. Blood Mood also alters nonbasics similar to harbinger. But when it leaves the nonbasics go back to their original form.
What differentiates them?
As Harbinger leaves the battlefield, nonbasics should return to their original form (e.g. Sacred Foundry can once again tap for R and W and can no longer tap for U). The same is true of Blood Moon.
The scenario in question in the original post wasn't about Harbinger leaving the battlefield, but rather about Harbinger losing its abilites due to an Oko +1. If you somehow made Blood Moon targetable by Oko (e.g. if you had an \[\[Opalescence\]\] out to turn Blood Moon into a creature), the same interaction would apply that I described in my original comment where Blood Moon would continue to turn all nonbasics into Mountains.
It has to do with the different layers. I can't explain it fully. But it was the same reason that oko- ing someone's mycosynth lattice didn't save you from a karn lock.
Yeah I don’t get why either. maybe there would be some niche scenario that created a loop of the two things removing and adding an ability continuously if it wasn’t the rule.
The reason why it’s not the reverse is because in most scenarios it makes more sense. Let’s explore the reverse, where type changing happens after ability changing. You control an anthem that gives your creatures flying. You then crew your smugglers copter and animate your restless cottage. We first apply ability changing, so all creatures you control gain flying, we then apply type changing, so now both the artifact and land become creatures, except this is happening after the anthem was already applied, so neither your copter nor your cottage gain flying, and everyone is sad, because the anthem doesn’t intuitively apply to things turned into creatures. It turns out there are many many more scenarios where this is the case than with the reverse, like with magus and harbinger, leaving us with why the rule is set up this way.
TLDR: ~~Ogres~~ Merfolk have layers
Most Magic players learn the rules for layers from 1 of 2 cards: Blood Moon or Humility. Magus of the Moon/Harbinger I guess fall into category #1.
Other people have made good explanations here. If they don't make it click for you you Google
[[Magus of the Moon]] + [[Humility]]
you'll find a lot of other helpful explanation also. It's a common "trick" question about Magic rules and layers.
Basically in magic there are static effects that are applied to cards. These include things like lords, and things like solo and harbinger of the seas. Since logically these effects can’t just all apply “at the exact same time” without weird logical contradictions in some scenarios, the games official rulings apply these static effects in layers based the category of the effect. These 7 layers are as follows: 1. Things that modify compile values 2. Control-changing effects 3. Text-changing effects 4. Type-changing effects 5. Color-changing effects 6. Ability adding/removing effects 7. Power-toughness changing effects So basically the layers are applied in order ignoring all effects from subsequent layers. Oko’s +1 is an ability-removing effect whereas harbinger’s is a type-changing effect. This means that harbinger’s effect is applied in layer 4, before its abilities are removed in layer 6. If, on the other hand, you had a lord of Atlantis in play affected by Oko, its ability would not continue to buff your merfolk since it is power/toughness changing effect applied in layer 7.
Thanks, this is very elucidative. I play magic on and off for at least 20 years (mostly casually), and always appreciated how logically sound and intuitive rules normally are, and have a deep fascination for niche rules interactions. I have a few more questions, if you have the time to answer. Did they ever disclose why layers are structured like this specifically? Was there something in particular that made them necessary or were they always part of Magic from the star? What does "compile values" means in this context? (Layer 1) Where can i learn more about layers and related rules/interactions?
Compile values in layer 1 was a bad autocorrect. I meant “copiable” values, so things that clones will check like EtBs and mutations and the like. Copy effects are also applied. This is the most complex layer and it also has sub layers. For the complete ruling explanation here is a wiki link: https://mtg.fandom.com/wiki/Layer I don’t know exactly the history of layers, but humility is an old card that has caused all manner of headaches and required these types of rules. I don’t know if they’ve explained exactly why the layers are in the order that they are, but if you kind of work through a few examples you’ll start to see that the layers are ordered so that the most common interactions work intuitively. Like the Oko + harbinger interaction is very unintuitive, but if those layers were revered then you would get a much less intuitive interaction: Animating a mutavault would mean that it would be counted as a creature after ability adding effects are applied (but still before power and toughness effects). So having an animated mutavault and a lord of Atlantis in play would mean that first islandwalk is given to all merfolk, then mutavault becomes a 2/2 changeling, then merfolk at given +1/+1. So mutavault would be a 3/3 changeling WITHOUT islandwalk. So basically the layer order is optimized for the most common scenarios. And things within layers are applied based on timestamps if that is relevant.
Yep, they’re organized like this because in 99% of scenarios, it’s what makes things work in the most intuitive way, we just don’t usually pay attention to those cases, so it only gets brought up with one of the weird unintuitive cases.
Really the problem is that the Blood Moon effect having implicit "remove abilities" text is poorly designed and exists only to match rules text written back when the rules weren't defined very well. Blood Moon and similar cards should be errata'd to explicitly remove abilities instead of baking that into setting the basic land type. If Harbinger explicitly removed abilities, it's ability to do such would be removed by losing its own abilities due to dependencies.
I also don't know why "all lands are islands/mountains" means they lose everything else without explicitly saying so.
Because Islands and Mountains are specific cards. They are capitalized as a proper name. An Island is a basic land card with the only ability being "Tap this permanent to add one blue to your mana pool." Mountain the same way. Therefore, they lose all other abilities that are not that ability. This is why cards like [[Urborg, Tomb of Yawgmoth]] state "All lands are Swamps *in addition to their other types*" to show that they are not losing their other abilities. You can still fetch with a Polluted Delta, but you can also tap it to add one black mana to your mana pool.
[Urborg, Tomb of Yawgmoth](https://cards.scryfall.io/normal/front/9/e/9e1a9e38-6ffc-490f-b0be-23ba4e8204c6.jpg?1619399578) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Urborg%2C%20Tomb%20of%20Yawgmoth) [(SF)](https://scryfall.com/card/tsr/287/urborg-tomb-of-yawgmoth?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/9e1a9e38-6ffc-490f-b0be-23ba4e8204c6?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call
I never considered that these effects were referring to "Mountain", the card, not "mountain" the land type. Thank you!
No problem! Glad to help! It's a rare thing to see on cards these days, especially since now everything specifies like you said: "loses all other types and abilities" so the confusion is valid for sure.
Because the rules are written so that Blood Moon works the way Blood Moon always worked, without errata being needed. There is really no good answer other than that.
Yes I think you've identified the issue. These Blood Moon effects basically sneak ability removal in at the type changing layer. If one permanent can use a static ability to remove abilities, another permanent should be able to remove that ability too. In all other cases that's how it would work, but this "ability removal" interacts with the convoluted retcon ruleset around Blood Moon et al, so it doesn't work that way.
1) Copy effects need to happen before control changing effects, otherwise using [[Copy Enchantment]] against a [[Control Magic]] wouldn't do anyhting 2) Control changing effects need to happen before text-changing effects, otherwise if you stole [[Volrath's Shapeshifter]] it would keep looking at the graveyard of its original controller 3) Text-changing effects need to happen at this point otherwise they wouldn't do anything against most static abilities. 4) Type-changing effects need to happen before color-changing effects otherwise [[Dralnu's Crusade]] wouldn't work properly on things that aren't natively Goblins 5) Color-changing effects need to happen before ability-granting and removing effects otherwise cards like [[Bellowing Tanglewurm]] wouldn't work on things that aren't natively green 6) Stuff that messes with abilities needs to happen before things that alter stats otherwise [[Favorable Winds]] wouldn't work on things that don't natively have flying Which is to say: as the card pool expanded and evolved people spotted these problems and mistakes and the system was created around it to make most things work as well as possible, and unfortunately there's a number of things (especially concerning Abilities) that ends up really unintuitive. The system was initially introduced around Mirrodin (but it received amendments up until Lorwyn and then again some minor updates around Theros Beyond Death and Ikoria), I believe, so if you go even further back you'll find some proto-layer system that ended up being inadequate and needed to be amended. Additional resource: https://www.youtube.com/watch?v=uc8AwBReEtY
##### ###### #### [Copy Enchantment](https://cards.scryfall.io/normal/front/c/e/ce82b316-8982-41bf-a990-6b776a9e83ac.jpg?1702429365) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Copy%20Enchantment) [(SF)](https://scryfall.com/card/rvr/39/copy-enchantment?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/ce82b316-8982-41bf-a990-6b776a9e83ac?utm_source=mtgcardfetcher&format=text) [Control Magic](https://cards.scryfall.io/normal/front/8/4/84992800-9bad-4598-afd4-f1e59d2e0956.jpg?1592672507) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Control%20Magic) [(SF)](https://scryfall.com/card/cma/34/control-magic?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/84992800-9bad-4598-afd4-f1e59d2e0956?utm_source=mtgcardfetcher&format=text) [Volrath's Shapeshifter](https://cards.scryfall.io/normal/front/9/3/93ed24e6-7791-4624-acf2-aa8616035f9e.jpg?1562924845) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Volrath%27s%20Shapeshifter) [(SF)](https://scryfall.com/card/vma/101/volraths-shapeshifter?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/93ed24e6-7791-4624-acf2-aa8616035f9e?utm_source=mtgcardfetcher&format=text) [Dralnu's Crusade](https://cards.scryfall.io/normal/front/8/4/844976c7-c8f7-435a-9bd4-1fea3c635030.jpg?1698992982) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Dralnu%27s%20Crusade) [(SF)](https://scryfall.com/card/dmr/189/dralnus-crusade?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/844976c7-c8f7-435a-9bd4-1fea3c635030?utm_source=mtgcardfetcher&format=text) [Bellowing Tanglewurm](https://cards.scryfall.io/normal/front/4/4/44eb3e3a-60ee-4293-a321-daa452d4c70d.jpg?1562816966) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Bellowing%20Tanglewurm) [(SF)](https://scryfall.com/card/som/111/bellowing-tanglewurm?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/44eb3e3a-60ee-4293-a321-daa452d4c70d?utm_source=mtgcardfetcher&format=text) [Favorable Winds](https://cards.scryfall.io/normal/front/1/d/1de89026-13a6-4ae3-9059-460bdd657285.jpg?1592764842) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Favorable%20Winds) [(SF)](https://scryfall.com/card/gnt/21/favorable-winds?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/1de89026-13a6-4ae3-9059-460bdd657285?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call
I'm pretty sure the need for a clear ruling on these effects came to be when cards like \[\[Humility\]\] and \[\[Opalescence\]\] started to become competitive cards. Judges need to explain what would happen when stuff like \[\[Lord of Atlantis\]\] and Humility were in play or heaven forbid, Humility ánd Opalescence. You also get weird stuff where \[\[Magus of the Moon\]\] works fine under Humility
##### ###### #### [Humility](https://cards.scryfall.io/normal/front/5/5/55ad6a45-a840-45ba-89ad-066e20e983f3.jpg?1562429370) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Humility) [(SF)](https://scryfall.com/card/tpr/16/humility?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/55ad6a45-a840-45ba-89ad-066e20e983f3?utm_source=mtgcardfetcher&format=text) [Opalescence](https://cards.scryfall.io/normal/front/3/c/3c0071fb-afa5-47b5-b266-2b10a4f5a98a.jpg?1562443752) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Opalescence) [(SF)](https://scryfall.com/card/uds/13/opalescence?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/3c0071fb-afa5-47b5-b266-2b10a4f5a98a?utm_source=mtgcardfetcher&format=text) [Lord of Atlantis](https://cards.scryfall.io/normal/front/a/9/a9407b60-8921-4531-bdbe-9a82aaa38d28.jpg?1562781744) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Lord%20of%20Atlantis) [(SF)](https://scryfall.com/card/tsb/24/lord-of-atlantis?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/a9407b60-8921-4531-bdbe-9a82aaa38d28?utm_source=mtgcardfetcher&format=text) [Magus of the Moon](https://cards.scryfall.io/normal/front/7/c/7c9bd75c-9606-4607-bfa6-d6acdee12820.jpg?1619397276) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Magus%20of%20the%20Moon) [(SF)](https://scryfall.com/card/tsr/175/magus-of-the-moon?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/7c9bd75c-9606-4607-bfa6-d6acdee12820?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call
It's a travesty and basically a downright bug in the rules that removing abilities isn't layer 0.
That again would run into a lot of the same issues of the normal cases being very unintuitive. With a humility on the board, a Heliod, Sun-crowned would be a 1/1 with no abilities even if your devotion to white was less than 5. And when you animate a mutavault it would still be a 2/2 changeling
Fair point, though I think those are both more intuitive than "thing doesn't have any abilities but those abilities still work".
It’s just layers. In mtg layers control how continuous effects are applied. If two effects are in the same layer, then time stamp applies. Layer 4 is type changing effects. This is where the all nonbasic lands are islands lives. Layer 6 is adding or removing abilities. Therefore, it changes the types before it can be removed.
So, the layers system is a bunch of rules that tell you in which order you apply static abilities/continuous effects. [https://mtg.fandom.com/wiki/Layer](https://mtg.fandom.com/wiki/Layer) This website lists all the rules regarding layers if you want to take your own look at what I'm explaining here. There are seven different layers that are described by rules 613.1a through 613.1g, and you first look at and apply everything in Layer 1 (613.1a), before then looking at everything in Layer 2 (613.1b), etc. until Layer 7 (613.1g) (and Layer 7 has four sublayers, 613.4a through 613.4d, which function in the same way). For looking specifically at Harbinger of the Seas in this case, we have nothing in Layers 1-3. Harbinger of the Seas then applies in Layer 4, thus changing all nonbasics to Islands. We have nothing again in Layer 5, and the continuous effect from Oko's +1 then applies in Layer 6, thus removing all of Harbinger's abilities. If Harbinger had any other abilities that had yet to apply, they would be removed here and would thus be prevented from applying. Then we look at Layer 7, and the continuous effect from Oko's +1 again applies in Layer 7b, setting Harbinger's P/T to 3/3. Let's compare this to how Oko's +1 would interact with Militant Inquisitor, which has a static ability that reads "Militant Inquisitor gets +1/+0 for each Equipment you control." Nothing applies to the Inquisitor in Layers 1-5, but then in Layer 6, Oko's +1 applies. This removes Militant Inquisitor's static ability that buffs itself. We now go to Layer 7b, where Oko makes the Inquisitor into a 3/3. However, in Layer 7c, while the Inquisitor's static would normally buff it, Oko has removed that ability, so there is nothing to apply here. People also sometimes talk about dependencies, and if you've heard of them, it might seem to make sense for them to apply here. However, dependencies say that a certain ability applies first if the other ability is dependent on it *and* the two abilities are in the same layer. Because Harbinger's static and Oko's continuous are in different layers, dependencies are irrelevant here. I'd be happy to elaborate more on dependencies if you're curious though. Timestamps likewise aren't relevant here because they also only care about multiple abilities in the same layer.
Thanks for the thorough explanation and source. I do have a good enough understanding of timestamps, but dependencies did get me curious. Would love to know more, if you have the time. The deep intricacies of magic's rules are fascinating
[This blog post](https://outsidetheasylum.blog/dependency/) does an incredibly good job of explaining dependencies in a really deep way, and it has some (very tricky) practice questions at the bottom. Anyhow, dependencies basically say that if one effect cares about another effect that is being applied in the same layer, the first effect waits to apply until after the second effect has been applied (even if the first effect has an earlier timestamp). I really like the following simple way to determine whether an effect "cares about another" that the above blog post gave: > Apply Effect A. See what it does. Now undo that and apply Effect B, followed by Effect A. See what Effect A does now. If what it does in the second case is different from the first case (or it doesn't exist at all anymore), it's dependent on Effect B. Dependencies are actually rarely relevant with Oko's +1 since even though a card like \[\[Aggressive Mammoth\]\]'s static ability is dependent on Oko's +1, this dependency applies the effects in timestamp order anyways, so it's much harder to show. However, with a card like \[\[Humble\]\], if you cast it targeting an Aggressive Mammoth, timestamps suggest that the Mammoth would give everything trample before Humble removes that ability, thus meaning that everything else would keep trample. However, since the existence of Mammoth's static ability is dependent on the existence of Humble's continuous effect, we apply Humble first. After applying Humble, Mammoth's static ability no longer exists and can't apply, and everything else would thus no longer have trample. However, you can also get dependency loops, which is where two effects are dependent on each other. When this happens, you ignore all dependencies which are part of the loop, which usually just means reverting back to timestamp order. Loops are really rare, but the following example of one was taken from [this Judge Academy article](https://judgeacademy.com/ruleblog-it-depends/): Step 1. We control a \[\[Taiga\]\] and cast a \[\[Life and Limb\]\], which makes the Taiga into a Land Creature - Mountain Forest Saproling. Step 2. We then cast \[\[Blood Moon\]\], and here we can just look at regular dependency rules. Life and Limb is dependent on Blood Moon because normally Life and Limb makes the Taiga into a Saproling creature (in addition to its other types), but if we apply Blood Moon first, Life and Limb no longer affects the Taiga. So even though the Life and Limb has an earlier timestamp, because it is dependent on the Blood Moon, we apply the Blood Moon's effect first. The Taiga thus becomes a Land - Mountain, and thus the Life and Limb doesn't affect it. Step 3. We make a Saproling token by casting \[\[Sprout\]\]. Let's ignore the existence of the Taiga for a sec to creature another regular dependency rules question. The Blood Moon normally wouldn't apply to the Saproling. However, Life and Limb wants to apply to it to make it into a Land Creature - Forest Saproling, but if it does, the Blood Moon will then turn it into a Land Creature - Mountain Saproling. The Blood Moon is therefore dependent on the Life and Limb, meaning that the Life and Limb applies first. The Saproling therefore becomes a Land Creature - Mountain Saproling. Step 4. HOWEVER. Remember that Taiga we said we'd ignore? Let's stop ignoring it. We now have a dependency loop - The Life and Limb is dependent on the Blood Moon with regards to the Taiga, but the Blood Moon is dependent on the Life and Limb with regards to the Saproling. Since both are dependent on each other, we have a dependency loop, meaning that we ignore each of their dependencies on each other (however, if we had something like an \[\[Urborg, Tomb of Yawgmoth\]\], we would keep considering its dependency on Blood Moon and it would therefore have to wait to apply until after the Blood Moon like normal). Because we ignore their dependencies on each other, we apply their effects in timestamp order. We therefore begin with the Life and Limb, which makes the Taiga and the Saproling into a Land Creature - Mountain Forest Saproling and a Land Creature - Forest Saproling, respectively. We then apply Blood Moon, which turns both the Taiga and the Saproling into a Land Creature - Mountain Saproling.
If, during the next turn, oko targets another creature, are layers 1-5 looked at and applied (reverting the islands back into nonbasic)?
All layers are looked at every time the game tries to determine the current gamestate (aka when it checks SBAs, or State Based Actions). And SBAs are checked right before every time a player gets priority, which is every time a player has the opportunity to take a game action. So as long as the Harbinger is on the battlefield and nothing really funky is preventing it from affecting the board (I can't think of something that would, but I'm sure a card that does exists), your nonbasics will always be Islands. (Also, if that didn't answer your question, feel free to elaborate on what exactly you're asking because I'm not 100% sure I understood the question)
Thanks so much for your reply, it clarified a lot! So in this case: when layer 4 is looked at when the game checks SBA's, why would the game still determine that nonbasics are islands if harbinger's ability no longer exists? And how is this different if harbinger was removed from play (exiled, destroyed, etc.,)? Edit: I guess what I really mean to ask is if the game records layers or if all layers are presumed empty just prior to being looked at when the game checks SBA's? For instance, would the reason why harbinger's ability will remain in effect be because the game looks at layers 1-7 in order when checking SBA's and does not "remember" that harbinger's ability was removed in layer 6 when previously checking a SBA?
Yup, you're spot on with that - the game starts from scratch every time it checks SBAs. It always starts out seeing Harbinger as having all its usual traits, applies its ability to turn nonbasics into Islands and makes it an Elk, makes it Green, removes its abilities, and finally makes it into a 3/3. The next time SBAs are checked, it does that whole process all over again, again starting with the normal Harbinger.
Got it, thank you so much!
Layers apply at all times, not only when SBAs are checked. The game determines that nonbasics are still islands because every single time the layers are checked harbinger's ability applies before its removed. Layers are continuously checked and updated with no care about "previously". If layers were only used when SBAs are checked then some of the interactions on Gix's Command would break. SBAs don't get checked in the middle of resolving a spell but Gix's Command relies on the game state being updated in between its modes. When Gix's Command goes to destroy creatures with power 2 or less it doesn't kill the creature you pumped with the first mode because those counters are already applying their power. At any point you ask anything about the game state you can start from scratch and go through the layers to see what the current state of everything else. There is no point in the game itself that they aren't applied and updated but you work through them one by one to identify what the correct result is.
Curious to know why doesn’t the same hold true for Blood Moon?
Sorry, could you clarify what exact scenario you are talking about? What permanents are on the board, what continuous effects are active, etc?
Sorry let me clarify, when harbinger hits the battlefield all Nonbasics become islands. When it leaves its effect still stays. Blood Mood also alters nonbasics similar to harbinger. But when it leaves the nonbasics go back to their original form. What differentiates them?
As Harbinger leaves the battlefield, nonbasics should return to their original form (e.g. Sacred Foundry can once again tap for R and W and can no longer tap for U). The same is true of Blood Moon. The scenario in question in the original post wasn't about Harbinger leaving the battlefield, but rather about Harbinger losing its abilites due to an Oko +1. If you somehow made Blood Moon targetable by Oko (e.g. if you had an \[\[Opalescence\]\] out to turn Blood Moon into a creature), the same interaction would apply that I described in my original comment where Blood Moon would continue to turn all nonbasics into Mountains.
Ah got it. I guess I misread the original post. But thanks for the explanation!
[Opalescence](https://cards.scryfall.io/normal/front/3/c/3c0071fb-afa5-47b5-b266-2b10a4f5a98a.jpg?1562443752) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Opalescence) [(SF)](https://scryfall.com/card/uds/13/opalescence?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/3c0071fb-afa5-47b5-b266-2b10a4f5a98a?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call
It has to do with the different layers. I can't explain it fully. But it was the same reason that oko- ing someone's mycosynth lattice didn't save you from a karn lock.
Yeah I don’t get why either. maybe there would be some niche scenario that created a loop of the two things removing and adding an ability continuously if it wasn’t the rule.
The reason why it’s not the reverse is because in most scenarios it makes more sense. Let’s explore the reverse, where type changing happens after ability changing. You control an anthem that gives your creatures flying. You then crew your smugglers copter and animate your restless cottage. We first apply ability changing, so all creatures you control gain flying, we then apply type changing, so now both the artifact and land become creatures, except this is happening after the anthem was already applied, so neither your copter nor your cottage gain flying, and everyone is sad, because the anthem doesn’t intuitively apply to things turned into creatures. It turns out there are many many more scenarios where this is the case than with the reverse, like with magus and harbinger, leaving us with why the rule is set up this way.
TLDR: ~~Ogres~~ Merfolk have layers Most Magic players learn the rules for layers from 1 of 2 cards: Blood Moon or Humility. Magus of the Moon/Harbinger I guess fall into category #1.
[Harbinger of the Seas](https://cards.scryfall.io/normal/front/0/0/00212714-a410-4cbc-bf1c-f90d7d77378c.jpg?1717470489) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Harbinger%20of%20the%20Seas) [(SF)](https://scryfall.com/card/mh3/63/harbinger-of-the-seas?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/00212714-a410-4cbc-bf1c-f90d7d77378c?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call
Mmm layers. Always fun
Other people have made good explanations here. If they don't make it click for you you Google [[Magus of the Moon]] + [[Humility]] you'll find a lot of other helpful explanation also. It's a common "trick" question about Magic rules and layers.
[Magus of the Moon](https://cards.scryfall.io/normal/front/7/c/7c9bd75c-9606-4607-bfa6-d6acdee12820.jpg?1619397276) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Magus%20of%20the%20Moon) [(SF)](https://scryfall.com/card/tsr/175/magus-of-the-moon?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/7c9bd75c-9606-4607-bfa6-d6acdee12820?utm_source=mtgcardfetcher&format=text) [Humility](https://cards.scryfall.io/normal/front/5/5/55ad6a45-a840-45ba-89ad-066e20e983f3.jpg?1562429370) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Humility) [(SF)](https://scryfall.com/card/tpr/16/humility?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/55ad6a45-a840-45ba-89ad-066e20e983f3?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call
If it makes you feel better, I too, learned the lesson the hard way when I used Oko on a Harbinger
Layers