Thoughts on Reversing Decisions

Approximately 6 months after the addition of 4.8. Reversing Decisions to the MTR, a concept on which I already expanded here, MC Cleveland gave me several different situations where to consider applying that new section of the rules. One in particular prove very challenging, and is worth expanding on.


The situation

AP attacked with a Merfolk Branchwalker. Both players tracked down damage and AP said “Go”.
NAP immediately started untapping, had time to untap one land, at which point AP stopped them and said they wanted to play a land.

The judge ruled that this totally fell under Reversing decision and that allowing AP to play a land was reasonable. NAP appealed because they thought that once a play was made, it couldn’t be taken back.

The reason for appealing the ruling is certainly not correct and, based on the situation as it was presented to me, I went to the table with the idea of upholding the ruling in mind, as the situation felt very straightforward:

  • AP realized almost immediately
  • It didn’t seem that extra information had been gained based on the description I was given.


The analysis

However, when I arrived at the table, things were a little different. Indeed, while NAP had only had time to untap one land (a Gate), it turned out that Gate was their only tapped permanent, as the other three Gates they control were already untapped. Several teachings from there:

  • Since there were untapped lands, by not performing any action, NAP revealed they didn’t intend to do anything. That’s arguably some level of information gained.
  • By immediately untapping (both players agree it was very swift), NAP possibly revealed that they actually have nothing to do at all.


Philosophy and Thoughts

The core of the issue is NOT that the action of untapping was entirely finished. This is a red herring. Reversing decision focuses solely on information gained, not the amount of time or any other element.

Allowing AP to reverse their decision to say “Go”, goes further than allowing them to sneak in a land on the battlefield: We actually fully rewind the game to Main Phase 2.
This means that if AP now wants to cast a spell, they can do so. This is not necessarily bad per se, however it’s important to understand that the consequences are possibly more than just playing a land.


The ruling

Do I believe AP gained information? I am not sure.
However the rules do not put the burden on the judge to prove that information was gained to disallow reversing the decision.

On the opposite, they explicitly say that allowing a decision to be reversed should only be allowed if the judge is certain that no information was gained: MTR 4.8 – “If the judge cannot be sure no information was gained, they should not allow the decision to be changed.”


I therefore chose to overturn the ruling and disallowed reversing that decision.


Tips and Tricks

You should not conclude from this situation that as long as there was one untapped land, then information was obviously gained. This isn’t that Manichean. I tried to come up with some general guidelines to have in mind:

  1. The “older” the format is, the more information was possibly gained
    Potential in Legacy is much higher than in Limited
  2. The more untapped lands the opponent controls, the more information was possibly gained
    When a player is tapped out, they can most often not play anything (though there are some free spells)
  3. The more cards a player has in hand, the more information was possibly gained
    When a player does nothing with many cards in hand, it means they possibly couldn’t do anything (if they do have mana available of course)
  4. The more time happened between the action and the moment the player would like to reverse it, the more information was possibly gained.
  5. An “ok” from the opponent doesn’t necessarily indicate that information was gained.
    This is especially true for actions that don’t use the stack and where the opponent doesn’t receive priority.

None of these guidelines are definitive.

There are situations where it’s totally reasonable to let a decision be reversed in Legacy or when a player has 10 lands untapped or has 7 cards in hand. But before doing so, it’s up to you to analyze the situation and analyze whether information was gained.


In any way, keep in mind that reversing a decision is not a right. It’s a privilege, from which players should not gain any advantage.

Kevin Desprez.