Deck checks

Being able to perform a deck check is a part of the L2 requirements. Actually performing a deck check isn’t objectively very difficult, but it is significantly different from the other sorts of things judges do, so it’s likely that you will need to practice before becoming truly proficient. Reading this will help, but like so many other things, real life experience will take you further. To that end, I recommend making up a decklist for your most recent 60 card deck with a 15 card sideboard and timing yourself to see how you do. Bonus points for timing yourself after your first time on the deck checks team at a tournament to see how much you improved.

What is the goal of a deck check?

We have two specific goals in mind when we perform a deck check. First, and most obviously, we’re trying to catch people who have done the sort of things we check for in deck checks: Marked Cards, Insufficient Shuffling, and Deck/Decklist Problems. The second purpose of deck checks is to disincentivize people from doing those things. I’d say the second purpose is even more important than the first. Truth be told, there aren’t a lot of people who cheat using these techniques. The vast majority of those penalties are for simple mistakes, and they feel awful to give. On the other hand, if there were no deck checks, the probability of catching someone doing these things would shrink to almost zero, and players would pick up on that. Even if removing deck checks didn’t result in a large number of new cheaters, it would certainly erode player confidence in the event integrity.

If you’re on the deck checks team, your work begins before the first game of Magic even starts. At the player meeting, or during deck construction in a limited event, you will have to collect the decklists.

  • First, and most importantly, put decklists in order while collecting them. If the players are seated alphabetically at the player meeting, that saves you a lot of work in organizing the lists later. Proper collection may involve putting lists on top or on bottom of the pile depending on which way you’re moving down the aisle.
  • If it’s a limited event, check decklists as players hand them in. Make sure that the player has basic lands registered, and check for the player’s name and table number, which help the deck checks team organize the lists. Another thing to look for is the “cheater’s downfall.” Often times, the deck registration sheets handed out at the event are modified in some way, for example, a random letter or design might be printed on the sheet, specific card names may be underlined or altered, or the sheet could be on a nontraditional color of paper. These measures prevent players from creating their own “sealed pool” at home, registering it, and then swapping it for their actual sealed pool during deck construction. As players turn in lists, make sure they have the expected modifications. Your head judge or team lead should tell you what to look for during the pre-event meetings.
  • After collecting decklists, standard practice is to first make sure that all the decklists are accounted for by checking player names off a list. Your team lead will coordinate your team’s efforts so that this can be accomplished efficiently.

The other “not deck checks” responsibility of the deck checks team is to count lists. Invariably, in a tournament of more than a few dozen players, one or more of them will make some form of registration error. Counting the number of cards registered in the maindeck or sideboard isn’t fun, but it does keep people from registering a 14 card sideboard and using the last spot as a “flex slot” to run whatever card they want in a matchup. Some things to keep in mind:

  • Most judging apps for smartphones include some sort of decklist counter. Becoming proficient with this tool can significantly improve your speed at counting lists.
  • Write the count in red near the top of the list so that everyone will know the list has been counted.
  • If you get numbers other than 60/15 on your count, the most likely reason for this is that you miscounted. Count again, or, better yet, ask someone else to confirm. If the numbers really are different, pull the list out and categorize it based on priority:
    • The “guaranteed gl”: less than 60 main, more than 15 board, banned cards, violations of 4-of rule
    • The “probable gl”: more than 60 main or less than 15 board when those numbers are written on the decklist, illegible number or card name
    • The “maybe we’ll get to it if we have time”: 61 card main or 14 card board, semi-ambiguous name or number that only really makes sense one way
  • Note: Counting decklists has become less important in the eyes of many head judges. Doing deck checks in round 1 is generally seen as higher priority. In this system, counting is relegated to periods where nothing else is going on, such as the time at the end of rounds when waiting for the last slip to come in, or before the player meeting on day 2 of a Grand Prix.

Before you can do a deck check, you need to first get the decks from the players. This is colloquially known as swooping. The name comes from the primary goal of this phase: to not be obviously about to deck check someone. No player is going to cheat if they know that you’re going to deck check them that round. Also, some may try to avoid the hassle by shuffling for a long time in the hopes that you’ll pick someone else. Here are some tips for swooping:

  • Deck checks are often done by pairs of judges. Opinions are currently divided on what your partner should be doing while you swoop the decks. Some say the partner should pull the decklists while you’re swooping so that the deck check can start as soon as you get back. Others hold that the two of you should swoop together so that if a player has a judge call near the table you’re swooping, the deck check can proceed as planned. Both sides have merit, and which way you go will largely depend on the needs of the event and your team lead’s guidance.
  • Watch the players shuffle. If you see a player only perform a couple riffles before presenting, you can give an Insufficient Shuffling infraction. On the other hand, if one or both players take an unreasonably long time to sideboard and shuffle, that’s Slow Play. I like to hand these infractions out after I’m done with the deck check because I think it’s less disruptive for the players than giving penalties two separate times. Also, in the case of Insufficient Shuffling, this allows you to examine the deck before infracting the player, giving you a chance to assess whether the lax shuffling may have been intentional.
  • When swooping, it’s important to make sure players have actually presented before taking their decks. Otherwise, if there are any problems, say a player forgot to desideboard, she can claim that she never presented and was going to change it. Rather than have that argument, it’s much easier if you simply wait until each player has touched her opponent’s deck before intervening.
  • Tell the players up front that they’re being deck checked. If you deck check a new player who’s never heard of deck checks before, what do you think is going through her mind if a judge comes up and tells her to hand over her deck? After a few deck checks, you should have a workable monologue that you can deliver when you take the players’ decks. It should cover the following points:
    • This is a deck check.
    • I need your decks and sideboards.
    • (If a midround deck check) We will leave your sideboard as you have presented it; please do not desideboard now.
  • If the player just hands you her deck and sideboard without the deckbox, ask for that too
    • in case you drop the deck, and
    • to check for the presence of illegal cards in deckboxes
  • When you swoop, be sure to remember which player has which deck. Otherwise, you can lose a significant amount of time during the check if you have to figure out what the difference between two similar lists is and then which is which.
  • Also note the time when you leave the table so that you can give players an appropriate time extension.

After all that work, it’s now time for a real live deck check.

  • The first thing to do is to check for Insufficient Shuffling. Unless you watched the player shuffling, it’s pretty tough to give this penalty on the basis of a deck check. After all, it’s possible to randomly get any distribution of cards. That’s how randomization works. On the other hand, if you see a pattern that’s extremely favorable to the player, such as a near-perfect land/spell distribution or a particularly nutty opening hand, it may be worth it to watch the player shuffle before she presents when you give the decks back.
  • The next thing you can do is check for Marked Cards. The first thing I do to check for this is square the deck up and look at the sides. All the cards should look the same, or very nearly so. If you can pick one or more out, that could be a problem. Here are some things to look for:
    • The corners of the sleeves are bent. Actually, I don’t really look for this. It’s an unfortunate fact of life that after a few rounds of tournament play, this can happen to sleeves. Unless there’s some kind of pattern (i.e., all the bent corners fit into some category, such as creatures, lands, or sideboard cards), I’ll return the deck with a “you really should consider replacing those sleeves soon,” but not issue a penalty.
    • The cards themselves are bent. Foils from some sets are worse than others when it comes to this. For instance, the MPR textless foils are notorious for bending. High humidity can also cause some foils, especially from older sets to warp significantly. Finally, players can damage cards intentionally and make them possible to pick out from the side. After your next draft, try bending a bulk common or land in your deck and see just how easy it is to bend it enough that it sticks out. If the bending looks accidental or beyond the player’s control, I’ll recommend manual unbending or acquiring other copies. If I see a non-foil that’s significantly warped, the player will have some serious explaining to do.
    • There’s something else about the cards that makes them easy to identify. This can run a pretty wide gamut. For instance, double-faced cards like Delver of Secrets should not be played in blue Dragon Shields because they aren’t completely opaque. This problem can only be solved by changing to checklist cards or opaque sleeves. You may also see a card be backwards so that the open end of the sleeve faces the opposite direction from all the other ones. This is easy to pick out if you’re looking for it, even if the sleeves have plain backs. Finally, it’s possible to intentionally mark cards to make them distinguishable from the side (see pictures). In all such cases, I’ll talk with the player and try to figure out what happened. Cases like these are more suspicious and tend to merit a higher penalty, so talk with the head judge if you run into any of them.
  • Finally, the last step, and the one that will take up the majority of your time: checking the deck against the decklist. Every judge has a system for this, and it’s important to pick a system that works with you and become proficient with it. What I recommend to judges who’ve never done deck checks before is to make one pass through the deck, moving lands to the front and creatures to the back as you go. This will leave you with three piles: lands, creatures, and everything else in the middle. From here, you can go down the decklist and pull each card from the appropriate pile. This method is much faster for me than, for example, sorting all the cards into their own piles, then going down the decklist. It’s also very easy to teach someone.
  • Note that midround deck checks will involve sideboarded cards. The way I handle these is by going down the decklist as normal. If I find a card on the decklist that’s not in the deck, I’ll look for it in the sideboard. As I get to these cards, I’ll put them “tapped” underneath the sideboard. When I check the sideboard, I’ll have a pile of cards from the main that weren’t checked off. I add these to the main deck as I go down the sideboard list.
  • It’s a good practice to check lands last when doing a deck check. Since lands are rarely sided out and most often written in their own section of the decklist, checking the lands is an easy way for your partner to help if you don’t finish about the same time. Lands are also the least likely thing for a person to attempt to cheat by changing. That means if you’re short on time, it’s possible to skip checking the lands to get the decks back sooner.

After you do the deck check, it’s time to give the decks back and get the players playing Magic.

  • Sometimes this involves giving a penalty. Deck/Decklist Problem penalties always suck to give out because a Game Loss is so severe relative to how easy it is to accidentally commit the infraction. For this reason, diplomacy with players is key. Here are some tips to make giving these penalties go more smoothly:
    • I like to bring the player’s decklist with me (of course, be careful not to let the opponent even glimpse it) in cases where there is a card not registered or misregistered. Disbelief is a somewhat common reaction here, and it helps to be able to show the player exactly what the problem is.
    • It’s also possible that the player might try to downplay the significance of their mistake. This is why it’s important for you to know the philosophy behind the Deck/Decklist Problem infraction and why it merits a higher penalty. Broadly speaking, it’s because errors like not registering a card or not desideboarding can potentially be greatly advantageous and are nearly impossible to detect otherwise.
    • Whenever possible, be direct but compassionate. When issuing the penalty, use facts to avoid sounding wishy-washy. D/DP is one of the most black-and-white infractions a player can commit, so don’t make it seem like they have room to negotiate. On the other hand, 9 times out of 10, you’re giving a game loss to someone who just made an honest mistake, so try to empathize with what they’re going through. Example: “This card was not registered on the decklist. This is an infraction called a Deck/Decklist Problem. Unfortunately, the penalty for a Deck/Decklist Problem is a Game Loss.”
  • Give an appropriate time extension when you’re done. The time extension should be equal to the time you took away from their match plus 3 minutes. Ordinarily, 9-10 minutes is a reasonable time extension for a constructed format deck check where you don’t need to talk to the players about anything. Two highly experienced judges checking a table can shoot for a lower time extension, perhaps 7 minutes.
  • Take care not to write anything on the match results slip that gives away private information. For example, “Did not register 4 Lightning Bolts” is not a good penalty description. If the opponent reads the back of the slip, she now knows four cards in the opposing deck. Better to write “Registered a 56 card maindeck” or similar.
  • Because it’s a relatively rare experience for a player to be deck checked, it’s important to take some time when you give the decks back to explain what happened and what that means. Points to cover:
    • If there were no problems discovered, say so and get the players back to playing Magic.
    • Remind the players that their decks have been sorted, so they should be sure to shuffle thoroughly. If it was a midround deck check, add that their sideboard configuration has been preserved as they presented, so there’s no need to re-sideboard.
    • If one player incurred an infraction for Marked Cards or Deck/Decklist Problem, it should be addressed away from the table to avoid giving information about that player’s deck away to the opponent. At the table, be sure to inform the opponent what the problem was and assure her that it’s been resolved.
    • If the deck check resulted in one player getting a Game Loss, explain that this player has the option to play or draw first in the next game they play.
    • If a player is given a Game Loss before the match begins, neither player can use sideboards for the first game they play.
    • If two players both get a Game Loss at the same time (not just for Deck/Decklist Problems, but for other things like Tardiness, too), the Game Losses offset and they play a normal match.
    • If you have to take the match slip away to issue a penalty, tell the players that you’ll be right back, but they can begin their game in the meanwhile. Otherwise, they may wait to start until you return, which is needless waiting for them and a potential delay of the tournament for you.


  • You can do deck checks even if you’re not on the deck check team. A good time to do this is if you catch someone Insufficiently Shuffling or with possibly Marked Cards. Remember, as a judge, you have a responsibility to intervene if you see an infraction, and those are infractions just as much as a GRV or Drawing Extra Cards.

And that’s about as much deck check tech as I can fit into one article. Hopefully, this will be helpful on your next (or first) time on the deck checks team. To recap:

  • Deck checks are important not just as a way to catch rule-breakers, but also as a tool to enhance perceptions of tournament integrity.
  • When you check a deck, look for Marked Cards and Insufficient Shuffling in addition to Deck/Decklist Problems.
  • Even if you’re at the point where deck checks are routine for you, most players aren’t. Some may not even know what a deck check is. It’s important to explain what’s going on both when you swoop and when you return.