Do I know which card an opponent revealed?

Question

When an opponent reveals a card in their hand, are players supposed to know when that card changes zones?

My instinct says no because

400.5. The order of objects in a library, in a graveyard, or on the stack can’t be changed except when effects or rules allow it. The same is true for objects arranged in face-down piles in other zones. Other objects in other zones can be arranged however their owners wish, although who controls those objects, whether they’re tapped or flipped, and what other objects are attached to them must remain clear to all players.

However, rearranging objects doesn't necessarily mean making your opponent lose track of them. In MTG Arena, a card revealed is shown face up in your opponent's hand at all times. Thus, you know if the card leaves their hand. A good practical example of this mattering might be:

Your opponent returns shock from their graveyard to their hand. Later, they draw one or more cards, then cast shock. They either A) cast the shock that was revealed, or B) drew another shock and cast it.

A savvy player will probably cast the one that was revealed, but some players may accidentally cast the recently drawn one instead. In MTG Arena, I would know if this is the case, because there would be a shock on the stack, and a shock card revealed in their hand.

In normal Magic, is there supposed to be a way of remembering which one the revealed card is? Or is this a place where the gameplay of MTG Arena differs from regular MTG?

Answer 1

You only know a revealed card for the duration that it remains revealed.

The example of Shock moving from the graveyard to the hand is a bit nuanced (since the card isn't technically revealed, mechanically), so I'm going to start with a more direct representation of the question and move from there. Let's say you cast a card like Thoughtseize which causes your opponent to reveal their hand. In MTG Arena, this is represented by the game revealing all of those cards to you from that point onward. However, that's not quite feasible in paper Magic - in the vast majority of cases, you'll pick a card for your opponent to discard, and then they'll go back to holding their hand towards themselves. That is, even though the information was revealed to you, by default you don't continue to be able to see those cards. It would be impractical for the opponent to hold newly drawn cards in their hand and simultaneously have those previously revealed cards lying on the table, for example. The information is known, but it's up to you to remember what that information was.

When I was playing Standard regularly (circa Theros) and my opponents cast Thoughtseize targeting me, I would show my opponent my hand, and they would use a notepad to write down the cards that they saw. Later, as I played those cards, they would scratch off the name of the card that I played if it was in that list. This, I believe, is what the functionality of MTG Arena seeks to emulate. Knowing that information was revealed to you, but misremembering it, feels bad. Arena can leverage its nature as a computer game to assist you with that, by making sure that you don't forget what cards were revealed. (There are other aspects it helps you with, too -- in real life, the cards you can cast don't glow.)

Rule-wise, of particular interest are the rules for revealing cards:

701.15a To reveal a card, show that card to all players for a brief time. If an effect causes a card to be revealed, it remains revealed for as long as necessary to complete the parts of the effect that card is relevant to. If the cost to cast a spell or activate an ability includes revealing a card, the card remains revealed from the time the spell or ability is announced until the time it leaves the stack. If revealing a card causes a triggered ability to trigger, the card remains revealed until that triggered ability leaves the stack. If that ability isn’t put onto the stack the next time a player would receive priority, the card ceases to be revealed.

701.15b Revealing a card doesn’t cause it to leave the zone it’s in.

701.15c If cards in a player’s library are shuffled or otherwise reordered, any revealed cards that are reordered stop being revealed and become new objects.

The phrasing of 701.15a makes it pretty clear that a revealed card is only revealed for a short amount of time, and then ceases to be a revealed card. You know what the card is because it was revealed, and can do whatever you want with that information (such as write it down), but it doesn't stay revealed after that. By extension, cards moving from a public zone to a hidden zone (rule 400.2) work very much the same way. Everyone is allowed to know what that card is as it moves into the zone, but after that, it becomes hidden.

Some relevant excerpts from Rule 400 regarding public and hidden zones:

400.2 Public zones are zones in which all players can see the cards’ faces, except for those cards that some rule or effect specifically allow to be face down. Graveyard, battlefield, stack, exile, ante, and command are public zones. Hidden zones are zones in which not all players can be expected to see the cards’ faces. Library and hand are hidden zones, even if all the cards in one such zone happen to be revealed.

[...]

400.7 An object that moves from one zone to another becomes a new object with no memory of, or relation to, its previous existence.

To use your example, let's say your opponent uses Call to Mind to return Shock from their graveyard to their hand. During the announcement of the spell (rule 601.2c), they would choose the target for it - Shock. Because the card is targeted, everyone inside and outside the game knows which spell is going back to their hand. As soon as Call to Mind resolves, the Shock is moved to their hand, where it becomes hidden along with all the other cards they hold. You know what card it is, but it is now part of a hidden zone, and there are no other effects requiring the card to remain revealed. You don't get to see it once it's back in their hand.

Answer 2

Once a card stops being revealed, it should be considered indistinguishable from the rest of the hand. There is no direct rule that states this, but various rules imply that non-visible cards in hand should be considered indistinguishable or interchangeable. Rule 402.3 says

A player may arrange their hand in any convenient fashion and look at it at any time. A player can’t look at the cards in another player’s hand but may count those cards at any time.

and rule 400.5 quoted in the question also supports that interpretation.

In addition, we can look at the behavior of official game implementations to infer what the intended interpretation is. In Magic Online, cards that are revealed from any zone are added to the "revealed cards" (pseudo-)zone. Players are responsible for keeping track of which cards were revealed from which zones, and when those cards leave those zones.

I am having trouble finding a complete description of how exactly Magic Arena handles revealed cards, but there are simple ways of implementing it that are both consistent with the observations in the question and consistent with this interpretation. For example, Arena may remove a card from the revealed cards display whenever a card of the same name (or appearance) moves from that hand to a public zone.

Answer 3

In normal Magic, you do not get to track which card is which in an opponent's hand. See Hall of Famer Brian Kibler shuffling his hand - nobody can track through that, and nobody should expect to be able to.

For Magic Arena: you indeed get to see which card it is, but it's not an actual sign that that particular card is the revealed one.

Example: let's say you cast Thought Erasure revealing my hand, and discarding such that my only remaining card is Shock. You can see that I have a Shock in my hand (this is why Magic Arena says you don't have to write down the cards that are revealed). I draw another Shock, and cast Shock. It doesn't matter if I cast the one that's revealed or the one that isn't; the end result is I have one hidden card in hand. If I cast the one that's not revealed, the game hides the one that is revealed.

Example: let's instead of drawing Shock, I draw Cavalier of Gales. This card says "draw three cards, then put two cards from your hand on top of your library in any order". When I do this, you no longer know if Shock is still in my hand anymore. It could be, or not be. The game automatically hides all revealed cards in this case. It doesn't matter if Shock was the only card in my hand or if I was holding 5 cards, all of which were revealed - they all get hidden.

The only situation I don't know is if I have four Shocks when I play Cavalier of Gales. No matter what happens there are at least two Shocks left in my hand. Are those still revealed? I don't know, if anyone does please leave a comment and I will edit.