Inspired by this question; the gatherer rulings for Relentless Assault say that if it is not a main phase when it resolves, then there will not be additional attack and main phases. Is there a rule that explains this interaction?

I think I can understand why it works this way thinking about it logically, (it refers to "this main phase", and since it is not the main phase, "this main phase" simply isn't a thing that exists, therefore there is nothing after "this main phase"). But usually MTG comprehensive rules are more specific.

The only rule I found dealing with this in general is 500.8:

500.8. Some effects can add phases to a turn. They do this by adding the phases directly after the specified phase. If multiple extra phases are created after the same phase, the most recently created phase will occur first.

This doesn't mention what to do if the specified phase doesn't exist.

To clarify, I'm well aware that you cannot normally cast Relentless Assault unless it is your main phase, because it is a sorcery. But there are plenty of effects that would allow you to cast it during combat.


2 Answers 2


Reconsider rule 500.8, specifically

They do this by adding the phases directly after the specified phase.

Relentless Assault adds an additional combat phase after this main phase.

As the spell resolves, it will untap creatures that have attacked during this turn. Then it will attempt to add an additional combat phase, followed by another main phase, after this main phase. If the game isn't in a main phase, it is impossible to complete the additions.


You can't "add a phase after this main phase" if the game isn't in a main phase, so do as much as possible: Just untap the creatures.

609.3. If an effect attempts to do something impossible, it does only as much as possible.

I think you find it confusing because "this {something}" is not usually a check, but that's because "this {something}" is usually used as the subject of an action verb, and those aren't checks.

The core of the issue of making it more readable is that it's hard to make the following template conditional:

After {phase}, there is an additional combat phase followed by an additional main phase.

The most readable options looks like an intervening-if, which is a problem in of its own.

After this phase, if it's a main phase, there is an additional combat phase followed by an additional main phase.

Removing the conditional entirely isn't an option either. The conditional is required to forbid the creation of an attack phase and a main phase after the Ending Phase, and even Sundial of the Infinite doesn't bypass the Cleanup Step.

  • I guess I was hoping for a rule along the lines of “if an effect refers to ‘this [specific phase]”, and it is not the specified phase, the effect is impossible.” But it sounds like they left it up to inference.
    – GendoIkari
    Commented Jun 3, 2018 at 13:28
  • They couldve added something like "if it is a main phase" on the card to make it extra clear, but there arent that many ways to cast sorceries outside of their regular timing, so the text was balanced towards readability rather than redundant correctness.
    – Hackworth
    Commented Jun 5, 2018 at 16:26
  • @Hackworth, Easier said than done. The template is "After {phase}, there is an additional combat phase followed by an additional main phase." I don't see a good way of adding "if it is a main phase".
    – ikegami
    Commented Jun 5, 2018 at 19:16
  • Of course they could have also simply not had that restriction.. "after this phase, there is...". The situations in which that would make the card stronger would be extremely rare. Makes me wonder why had that limitation in the first place.
    – GendoIkari
    Commented Jun 5, 2018 at 19:25
  • 1
    @Ikegami that just goes to prove my point, which was less about the exact wording and more about readability vs. explicitness. Whatever wording they would have to use to make the card super duper obvious in terms of timing under all circumstances would decrease readability, and obviously they felt that the sorcery type was sufficient, if not 100% perfect, to get the point across. So they sacrificed a little bit of correctness and/or explicitness to gain a lot of readability.
    – Hackworth
    Commented Jun 6, 2018 at 7:30

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