In dark times, when judges were called “zebras,” Pro Tours weren’t streamed on Twitch, the Magic community lived in constant vigilance of the Drawing Extra…

Judge… I thought this was an article on the IPG?

Huh? Yes it is, but you need to be patient to—well, the mood is kinda gone now, so let’s resume the original plan!

Hello everyone, my name is André Tepedino, from Brasilia, DF, Brazil, and I’m going to talk about a very specific part of the IPG. In today’s class, we’re going to talk about one of the most significant changes in the Game Play Error (GPE) section in many years: the Hidden Card Error (HCE). Along with me today is my pal, the floor judge, who will be helping me explain a bit better how HCE works.

Hello everyone, it is a pleasure! Now, Judge, why were you taking a trip down memory lane?

Well, it was more to set a mood than anything. After all, the HCE infraction substituted one that was around for quite some time (though it wasn’t very popular): Drawing Extra Cards. DEC carried the penalty of a game loss but, more often than not, you’d stumble on a situation where player simply made an honest mistake, and a game loss for that was definitely a “feel bad” situation. Penalties are there to teach players, and an accidental draw that results in a game loss hurts far more than it teaches.

Ah, I see. And the Hidden Card Error changed that?

It did! With Hidden Card Error, judges could now mitigate the damage to the game state caused by drawing an extra card and allow the game to continue close to the way it should have if played properly.

Of course, moving a card from one zone to another incorrectly is still a big problem. In most cases, only the player that committed the infraction has information on the identity of the card. Based on the hard work of some high level judges, HCE was created to minimize some of the more “feels bad” situations, but still mitigate advantage and protect players from cheats.

Let’s start with the definition from section 2.3 of the IPG:

A player commits an error in the game that cannot be corrected by only publicly available information and does so without his or her opponent’s permission.

One second, Judge. It says “without the opponent’s permission”. Why is that?

One of the main reasons is so that players do not intentionally allow their opponent to commit HCE infractions. Also, once there is a confirmation of the action from the opponent, both players are aware of the action and, as we know, both players are responsible for maintaining a legal game state. So player A can’t allow player N to draw cards off a Divination while Spirit of the Labyrinth is in play, then call a Judge for HCE – it is their responsibility, too. And remember: knowingly breaking a game rule in order to gain an advantage is Cheating, for which we have a whole different set of penalties.

Let’s continue with the definition:
This infraction only applies when a card whose identity is known to only one player is in a hidden set of cards both before and after the error.

So… HCE only applies when the card came from and went to a hidden zone? I guess the name makes sense.

Errors where the card either came from or went to a public zone are easily identifiable and much simpler to fix. Therefore, they do not fall under HCE. If, for example, an Alabaster Dragon gets exiled and its owner shuffles it into their library, all players know the identity of the card, where it is, and where it should be, so we do not apply Hidden Card Error here.

Let’s finish up the definition:
This infraction does not apply to simple dexterity errors, such as when a card being pulled off the library sticks to another card and is seen or knocked off the library. The cards themselves must be part of a distinct set intended by the player.

To clarify, let’s take a look at the examples from the IPG:

A. A player draws four cards after casting Ancestral Recall.
B. A player scries two cards when he should only have scried one.
C. A player resolves a Dark Confidant trigger, but forgets to reveal the card before putting it into her hand.
D. A player has more cards in his hand than can be accounted for.
E. A player casts Anticipate and picks up the top four cards of her library.
F. A player, going first, draws for his turn.

We notice here that every example involves only one player knowing the identity of the cards that weren’t supposed to be seen. As much as we would like to believe everything players tell us, our rulings and fixes need to be applicable in all cases, regardless of feelings towards the players’ honesty.

So we don’t use the information the player gives us, Judge?

We do use the information in many occasions, but they’re usually not the determining factor in the rulings.

When it comes to Hidden Card Error, we have to accept that we won’t be able to fully fix the game state. Save rare exceptions, there will be information gained incorrectly that cannot be “un-gained”. In a game of Magic where information is everything, penalty philosophy tries to mitigate the consequences of such incorrectly gained information. Let’s take a look at HCE philosophy:

Philosophy
Though the game state cannot be reversed to the ‘correct’ state, this error can be mitigated by giving the opponent sufficient knowledge and ability to offset the error so that it is less likely to generate advantage.
If cards are placed into a public zone, then their order is known and the infraction can be handled as a Game Rule Violation. Order cannot be determined from card faces only visible to one player unless the card is in a uniquely identifiable position (such as on top of the library, or as the only card in hand.)
Be careful not to apply this infraction in situations where a publicly-correctable error subsequently leads to an uncorrectable situation such as a Brainstorm cast using green mana. In these situations, the infraction is based on that root cause.

Wait, Judge… what do you mean by “root cause”?

When dealing with Hidden Card Error, we always ask “what was the thing that caused this situation to be wrong?” Depending on the answer, it can be an HCE or not. We have the example of Brainstorm (a spell that costs one blue mana) being cast using green mana as a problem. However, what if the situation was that the player casted Brainstorm correctly, but drew four cards instead of three?

Then the problem is that the player drew an extra card.

Exactly! By determining the root cause, we can understand better what the problem is, identify the appropriate infraction and apply the correct fix.

It is important to remember that, when it comes to infractions, we always look for the root cause of the error, identify the proper infraction and apply penalties and fixes. We do not decide penalties or fixes based on “what’s best for the game” in our opinion. The rules went through a long process of studying and testing, and the application should be consistent throughout the judge program.

Consistency. All right, noted, Judge. Now… about the last two philosophy points…

We’ll go over them, don’t worry!

Information about cards previously known by the opponent, such as cards previously revealed while on the top of the library or by a previous look at the hand, may be taken into account while determining the set of cards to which the remedy applies.

Always operate on the smallest set possible to remedy the error. This may mean applying the remedy to only part of a set defined by an instruction. For example, if a player resolves Collected Company, picks up three cards with one hand and then four cards with the other, the last drawn set of four cards should be used for the remedy, instead of the full set of seven cards.

When it comes to information previously known, there are a variety of things that one can use: notes made about an opponent’s Thoughtseize can be used to determine which cards were already in hand, as well as cards revealed to a Lantern of Insight that was on the battlefield a few turns ago.

But… what if the opponent doesn’t remember?

That’s fine. While it is advantageous to know your opponent’s revealed cards, it is certainly not obligatory. If the other player does not remember cards from the player that committed the infraction, continue the remedy without that information.

Now, let’s talk about the “smallest set.” The first read may be counter-intuitive, as the philosophy first instructs us to operate on the smallest set, then gives an example in which we act on a set of 4, instead of a set of 3. Can you tell me why?

Because… well, because we are sure the first three cards are legal!

Exactly! Because the player in the example, when instructed to form a set of six, first picked three cards, then four more cards, we know for a fact that all of those three cards were part of the set of six. Consequently, that set has no problems, and we can leave it as it is. Since the player pulled three cards out of six, they should have pulled three more cards, but pulled four. One card should not be there, and we apply the remedy for the Hidden Card Error.

And if they had pulled four, then three, we would be operating on the set of three cards. Understood, Judge.

Excellent. Now that we know what we are looking for in a Hidden Card error, let’s take a look at the ways to fix the problem. This section is quite wordy, but it is simpler than it looks. Take a deep breath, and let’s dive into it (it may be helpful to follow along with your own copy of the IPG!):

Additional Remedy
In cases where the infraction was immediately followed by moving a card from the affected set to a known location, such as by discarding, putting cards on top of the library, or playing a land, a simple backup to the point just after the error may be performed.

If the set of cards that contained the problem no longer exists, there is no remedy to be applied.

If the error put cards into a set prematurely and other operations involving cards in the set should have been performed first, the player reveals the set of cards that contains the excess and his or her opponent chooses a number of previously-unknown cards. Put those cards aside until the point at which they should have been legally added, then return them to the set.

If the error involves one or more cards that were supposed to be revealed, the player reveals the set of cards that contains the unrevealed cards and his or her opponent chooses that many previously-unknown cards. Treat those as the cards that were ‘revealed’ and return them to the set that was being selected from; the player then reperforms the action. If recreating the original selection set and reperforming the action would be too disruptive, leave the selected cards in hand.
If a set affected by the error contains more cards than it is supposed to contain, the player reveals the set of cards that contains the excess and his or her opponent chooses a number of previously-unknown cards sufficient to reduce the set to the correct size. These excess cards are returned to the correct location. If that location is the library, they should be shuffled into the random portion unless the owner previously knew the identity of the card/cards illegally moved; that many cards, chosen by the opponent, are returned to the top of the library instead. For example, if a player playing with Sphinx of Jwar Isle illegally draws a card, that card should be returned to the top of the library.

To start, if we have an HCE where a card moved from the problem set to a public zone, we can use that information to put the cards back into the set before fixing the problem.
Example: Player A resolves Grim Flayer’s triggered ability, pulls four cards instead of three and throws two to the graveyard. We add the cards back to the set and apply the remedy.

Judge, when it says “the set of cards no longer exists”, if in your example they put the cards back on top… that means we don’t fix anything?

Depends on how “gone” the set is. If they put two cards in the graveyard, then put two cards back on top, we can still easily work on the set of four. If, however, things get too tricky (like the same example, followed by the player cracking a fetch land for a land and shuffling their deck), the set is now impossible to recreate the set, and you leave as it is.

Isn’t the player who committed the infraction getting too much advantage that way, then?

We must remember at all times that both players are always responsible for the game state. In the situation, A was supposed to look at three cards, looked at four, then took some time making choices on what goes to the graveyard, then fetched. All this time, N had the chance to point out that something was wrong, if they were paying attention to the game state.

I’m confused… HCE reminds me a lot of Mulligan Procedure Error; what makes them different?

Good catch! Mulligan Procedure Error and Hidden Card Error are quite similar!. However, due to the fact that Mulligan errors happen in pregame, there’s a less damaging fix that can be applied, which is giving the player who committed the infraction the option to mulligan. Because we want to encourage players to call us when they see a problem during pregame, we have MPE. As a reminder, from the moment they scry after the keep, we enter HCE territory (i.e. if they scry 2 after a mulligan to 6, we apply the HCE fix).

Judge, can you give me an example of “adding a card to a set prematurely?” I got a bit lost.

One simple example of this situation is Rummaging Goblin’s ability (Tap, discard a card: draw a card), where the player draws first before discarding. In this situation, we want to stop the player who committed the infraction from discarding a card that they could not (in other words, the card drawn). To make that as fair as possible, the player who committed the infraction reveals their hand to their opponent, who chooses the “drawn card”. That card is set aside as the card that was drawn, and we proceed with discarding the card.

The fourth paragraph applies to effects like Ajani, Mentor of Heroes or Ancient Stirrings: if A put the card in their hand without revealing, we have A reveal their hand to N, who now selects which card was chosen during the resolution of this ability.

What if N chooses a colored card for Ancient Stirrings, Judge?

If N chooses a card that would be an illegal choice for the ability, A will resolve the ability in question with that card in the set, revealing their choice and finishing the effect. If, by any chance, N chooses a legal card, then the effect resolved correctly, and the game can continue from there.

The last paragraph describes the fix we’ll probably see the most, which many call “the Thoughtseize fix” (perhaps more accurately called “the Perish the Thought fix”). If player A drew one card too many, we now have to take out one card so that they do not get an advantage. The best person in the game to say what card would give player A the advantage is, without a doubt, the opponent. Therefore, A reveals all the cards in their hand to B, who chooses a card to be put back in the library. Remember, cards put back in the library, if they were not previously known, should be shuffled.

We keep them there if they were known to avoid a free shuffle, correct Judge?

Exactly. The ‘Thoughtseize’ fix also applies to a scry 2 where the player looks three at cards, a Dig Through Time where the player looks at 8 cards. So, in short:
Check the Root Cause -> Determine the smallest set -> Reveal to the opponent, who chooses the affected cards -> repeat the action if necessary.

And in all of those, they get a warning as well?

Correct. Speaking of warnings, let’s talk about those more serious situations, in which things can’t be fixed or mitigated, for which harsher punishment exists: Upgrades. Hidden Card Error has one potential upgrade:

Upgrade: If a face-down card cast using a morph ability is discovered during the game to not have a morph ability, the penalty is a Game Loss. If the player has one or more cards with a morph ability in hand, has not added cards to his or her hand since casting the card found in violation, and has discovered the error themselves, the upgrade does not apply and they may swap the card for a card with the morph ability in hand.

Morph cards can be tricky. You can play the whole game without ever having to show it to your opponent, and its legality is only checked at the end of the game. If, however, you find out that a morphed card does not have morph, it is too much of an abusable situation, and the penalty is upgraded to a Game Loss.

The second sentence covers the error where the player only played the wrong card from their hand (like pulled the card right next to the morph one, or because they look alike), notices the mistake, and there’s still time to fix it. After all, if no cards were added to the player’s hand, it won’t happen that they played the morph in hopes of drawing a real morph card later on. For those cases, you don’t upgrade; instead you swap the card in play for the real morph card, and issue a warning.

Judge, do you reveal the morph card as you’re swapping it?

The IPG doesn’t specify, but since a judge is the one making the swap, they can verify the legality of the morph. As the IPG tends to mention when you’re supposed to reveal something, revealing is not necessary in this case.

Understood. Anything else, Judge?

Just a few considerations:

• HCE can be tricky. Proof of it is that, in major events such as GPs, the Head Judge tends to ask floor judges to confirm their HCE rulings with a Level 3 or a Team Lead;
• ALWAYS CHECK THE ROOT PROBLEM. Sometimes, untapping the lands before the illegal draw can show you that the player was just confused about turns, which is a different penalty;
• Do not go too far to fix a situation. If cards are shuffled away or are too hard to identify, it’s probably too late to fix;
• When in doubt, ask. There’s no shame in not knowing the answer and finding it for your players. I assure you they’ll like that way more than a wrong ruling.

Hidden Card Error may be a complicated infraction to fix. However, taking out Drawing Extra Cards from the Infraction Procedure Guide was, without a doubt, an improvement, as it better protects rookies in their first tournament and still gives far less space for abuse. I especially like the direction the IPG is headed, where we are finding more and more ways to fix the game state instead of ending a game with a penalty; though we still have harsh consequences for those who actually cheat.