Pile shuffling does not randomize a deck. Except during pregame, where pile shuffling allows players to count the number of cards in the deck, it might be considered a waste of time, and therefore considered slow play.

I see tons of players pile shuffle at large tournaments. I watch them pile shuffle while totally engulfed by hordes of judges because they are playing on camera. I always pile shuffle my deck during pregame to count cards. I pile shuffle my opponent's deck to do the same.

Is pile shuffling at a Magic: the Gathering tournament considered slow play, during pregame or otherwise?

This question is related to the question about Mana Weaving. The difference between the two questions is the actual, real-world experience I have at tournaments and watching video coverage. I've seen judges ask a players to stop mana weaving. I've never seen a judge ask a player to stop pile shuffling. So even though I would expect the answers to be the same from a strict rules standpoint, the answers appear to be different in reality.

If the answer depends on the REL, please answer for both Regular and Competitive.

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    As the referenced "other user", I think I should mention the discussion may have been about mana weaving, not pile shuffling. Mana weaving should have no effect when followed by proper shuffling. That means 1) it's a waste of time, 2) it's an attempt to cheat (you want it to have an effect), and 3) it creates a perverse incentive to not shuffle correctly.
    – ikegami
    Commented Mar 25, 2015 at 16:07
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    When I have time later today I'll see what I can find in the Judge Resources, a quick search isn't finding anything obvious but I may just be missing something right now.
    – diego
    Commented Mar 25, 2015 at 16:35
  • Pruning comments. Folks, I would suggest trying to recognize when you have crossed over from offering helpful suggestions to possible annoyance.
    – Pat Ludwig
    Commented Mar 25, 2015 at 21:46
  • I also deleted several comments that could have been answers. This isn't the right place for them.
    – Pat Ludwig
    Commented Mar 25, 2015 at 21:50
  • @Jefromi, I consider the following to be the question: According to the TR, pile shuffling doesn't randomize. ("Pile shuffling alone is not sufficiently random.") As such, if you pile shuffle when you are suppose to shuffle your deck, you are wasting time rather than performing the action you are suppose to be doing. Do judges issue Slow Play penalties for this?
    – ikegami
    Commented Mar 25, 2015 at 21:50

5 Answers 5


The tournament rules now clearly cover pile shuffling:

Pile shuffling alone is not sufficiently random and may not be performed more than once any time a deck is being randomized.

The description from the update bulletin explains a bit more:

Section 3.9 (Shuffling): This change has to do with "pile shuffling." Pile shuffling alone is not a sufficiently random form of shuffling. Update states that a player may only pile shuffle once each time a deck is randomized. The one pile shuffle is allowed in order to count the number of cards in the deck.

So, pile shuffle once, and you're okay, as long as you still actually shuffle your deck - it will not be considered slow play. Pile shuffling more than once would be against the rules, though it's not clear whether it'd be deemed slow play or just improper shuffling.


As far as I can tell, there is no rule that states that pile shuffling is unequivocally slow play or not slow play. As your question hints at, it depends on the judge and circumstances. If it is obvious someone is trying to waste time to force a match draw it would (or should, in my opinion) be called slow play. If it isn't hurting anything, I doubt it would get called. The slow play rule is to keep people from taking an excessively long time to do something (either for personal gain, ie forcing a draw, or to stop analysis paralysis).

Mana weaving is different in that it can only, at best, be a time waster. (If you are properly shuffling, it won't do anything.) At worst, it is a form of cheating because you are trying to stack your deck. In either case, it is best to avoid even the appearance that a tournament is allowing something that could be called cheating when that behavior has no possible legitimate use.

  • This type of shuffling is usually done at the start of the game. How can you tell if it'll hurt anything?
    – ikegami
    Commented Mar 25, 2015 at 21:24
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    @ikegami If you do it once at the start of a match, it's probably fine. If you do it 6 times every time you tutor or crack a fetch land and there is 30 seconds left on the round clock and you are losing, that's different. Granted I will never be able to predict when the loss of a second here and there will change anything. That's why the judges are there and why the correct ruling would have to be based on context. I could replace "pile shuffling" with "shuffling in a slow manner" and the answer is the same. If a judge thinks you are taking too long, they call it. That's up to them tho.
    – Becuzz
    Commented Mar 25, 2015 at 21:31
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    Re <<I could replace "pile shuffling" with "shuffling in a slow manner" and the answer is the same.>>, No, it's not. Pile shuffling isn't randomizing, so you aren't doing what you are suppose to be doing. You are purely wasting time. You still need to randomize your deck afterwards, which you may or may do slowly.
    – ikegami
    Commented Mar 25, 2015 at 21:32
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    "trying to waste time to force a draw" is Cheating - Stalling. "Slow Play" is by definition unintentional.
    – Affe
    Commented Mar 27, 2015 at 18:24

Pile shuffling one time before a game starts is not slow play. Pile shuffling has a way of significantly transforming the starting configuration of your deck and washing away all patterns that used to exist due to clumping (while possibly introducing new and very different-looking patterns). Because it is deterministic, it can have a way of putting the final configuration of your deck into a predictable pattern if the starting configuration was known and easily memorized. This is why, if you rig your deck between rounds, and immediately go into a pile shuffle when you first sit down for a match, you can use it to stack your deck or mana weave (i.e. cheat). But if you perform even one riffle shuffle before you begin pile shuffling, then all of the deterministic aspects of pile shuffling are negated and it can't be effectively used in any cheat (other than possibly rigging the top / bottom card of your deck).

An aside about randomization: if the final configuration of a deck is even a little bit influenced by the starting configuration of the deck, then it is not randomized. For instance if a Dark Ritual was adjacent to a Phyrexian Negator, and they remained adjacent during your entire shuffling ritual, then it is not randomized. If your deck starts out with a better-than-random mana distribution, and you perform a series of riffle shuffles in which it consistently sustains a better-than-random mana distribution after each shuffle, then it is not randomized.

So anyways, my studying of deck randomization has revealed that dozens of riffle shuffles are less effective at washing away the starting patterns of a deck's configuration than a single riffle shuffle followed by a pile shuffle. This is especially so because some sleeves tend to stick together a bit, and are capable of sticking together through the course of quite many riffle shuffles, therefore tenaciously preserving information about the starting configuration of the deck. A lazy riffle shuffle that interweaves large clumps of cards can fail to erase certain deck configuration properties, such as weaved mana (i.e. if your deck is perfectly mana weaved, and then you perform a loose riffle that drops clumps of 8 cards at a time, you will likely find that the deck is still highly mana weaved) or combo cards that are adjacent to one another. That is why I would say that a mixture of riffle and pile shuffling is not a slow way of randomizing your deck, but actually a faster way of really randomizing it. If you can fully randomize your deck at the beginning of a match in under 3 minutes, then you should not be worried about violating slow play rules. However, magic's historical convention for sufficient randomization required at least 3 riffle shuffles, and I would not recommend any shuffling algorithm in which fewer than 3 riffle shuffles are executed (regardless of what additional actions you are performing instead).

Performing more than one pile shuffle creates numerous issues. First, it can be used to mana weave a deck. Second, there is a way to perform two pile shuffles in a row such that it restores the deck back to its original configuration before you started the pile shuffle, and if you also rigged the order of your deck before the match begin, then this would execute the ultimate cheat -- the fully stacked deck from top to bottom. Third, two pile shuffles is just as deterministic as one pile shuffle, and does not provide any greater randomness, nor any greater ability to separate adjacent cards than a single pile shuffle provides. Fourth, two pile shuffles takes twice as long as one pile shuffle.

Another thing to consider is the timing of a pile shuffle.

  • Since a deck's state at the beginning of a match is not known to be random, and could in fact be rigged, significant randomization effort should be taken before the first game begins. This is the time in which a pile shuffle is most justified. A pile shuffle is more likely to be an authentic attempt at randomization and not a cheat if at least one riffle is performed first.
  • Once players are done with their opening randomization rituals, provided that a player does not like their opening hand and proceeds to mulligan it, their follow-up randomization ritual should not be as long as the first one. This is because the deck has already been sufficiently randomized once (and if it wasn't, then they already violated a rule), the player has no way of knowing whether the rest of their deck is also badly clumpy, aside from being slightly skewed by subtraction of the 7 cards they did see (unless they do know, which means they know their deck wasn't sufficiently randomized, which violates a rule). So the follow-up shuffling ritual is starting from a fairly randomized point, and should not take significantly more randomization to get it to a new randomized state (in other words, a second pile shuffle at this point is not justifiable). Some players indeed get away with pile shuffling after taking a mulligan, but I think a judge would at least look at the total context of how the match is progressing, if either player is up a game, how long the entire shuffling ritual is taking, and the pace of play.
  • Once a game begins, if a player is forced to shuffle their deck due to a game rule such as sacrificing a fetchland, then a pile shuffle is very much not justifiable, and could well be considered stalling. Some decks require to be shuffled dozens of times per match due to game rules like fetchlands, tutors, etc.; and a one-minute shuffling ritual for each game rule for each player could all by itself eat-up more than the match's allotted time, which is why you should strive to get some riffle shuffling done efficiently and very quickly.
  • After each player performs sideboarding, it is likely that they have seen the exact configuration of their deck (but it is unlikely that they are capable of memorizing it). It is possible that they picked-up the cards from their previous game in a way that simulates a partial mana weave. The player might have inserted their sideboard cards into their deck in an even distribution. All of this puts their deck in a more favorable than random state. However, it is not a state that is rigged well enough to then mana weave it using a pile shuffle. Since it is currently in a more favorable than random state, two strategically executed pile shuffles would preserve the current order of the deck, and produce an end result that is more favorable than random (therefore, two pile shuffles at this point could be used for cheating). In other words, the deck is in a state that is less random than when players take their first mulligan, but more random than when they sit down for a match, so a reasonable shuffling ritual here should be one that is just slightly faster than the beginning of match's shuffling ritual (i.e. 0-1 pile shuffles and several riffles). There is no reason why a riffle shuffle would be obligatory before a pile shuffle at this point, provided that the player did not have an opportunity to rig their deck in all-lands and all-spells clumps. Depending on the total context of the match's progress, you can probably get away with a 3-minute shuffling ritual at this point, but my personal belief is that it should be capped at closer to 2.5 minutes.

On another note related to cheating with pile shuffling, I should say that at an event with a REL level, you might fail a deck check if you sit down for a match with a deck that is already in a rigged state (i.e. all spells on top and all lands on bottom).

  • Interesting point about clearing away physical issues/stickiness, but to say that a pile shuffle doesn't preserve ordering after a single riffle shuffle is false. You know less only because of the riffle, but you still have more information than random. Ignoring physical issues, however, you mention that adding a pile shuffle to a series of riffle shuffles improves the ability to break up segments. However, since pile shuffling adds apparent randomness but no actual randomness, this is a perceptive bias. ~
    – Samthere
    Commented May 11, 2018 at 15:06
  • ~ Thus if a pile shuffle, in general, seems to improve the randomness of your shuffle, then your shuffle is not sufficiently randomising the deck. A pile shuffle has no impact on the randomness of the deck. The problem with pile shuffling is that, if people learn (as you observe) that throwing in pile shuffling improves the apparent randomness of their normal shuffling, then they never learn/take the effort to carry out shuffling that leads to results that are sufficiently random.
    – Samthere
    Commented May 11, 2018 at 15:09
  • Welcome to Board & Card Games SE, John! Great observation about the physical issue of sleeves adhering to each other.
    – Alex P
    Commented May 11, 2018 at 16:26
  • It's good to challenge the premise of a question (in this case, that pile shuffling does nothing to randomize a deck), but I don't agree that one riffle and one pile shuffle is better at randomization than dozens of riffles. It's a fact that pile shuffling is deterministic. You found false success with this method because you incorrectly defined success as "eliminating starting patterns". I can eliminate starting patterns too by pile shuffling a deck of 30 lands followed by 30 spells into a deck that is perfectly alternating lands and spells.
    – Rainbolt
    Commented May 11, 2018 at 16:40

This is the type of thing that is abstract enough that it will depend on the judgement calls of judges at a specific event. I can imagine situations where this can be true and untrue.

So for instance, if you are in match 6 at a Grand-Prix and the match is tied up one game a piece. It suddenly becomes clear to one player that he cannot win anymore and suddenly he wants to pile shuffle every time his opponent cracks a fetch land, then it is very much against the rules. He is wasting time to gain an advantage by getting the match to go to time.

I see tons of players pile shuffle at large tournaments. I watch them pile shuffle while totally engulfed by hordes of judges because they are playing on camera. I always pile shuffle my deck during pregame to count cards. I pile shuffle my opponent's deck to do the same.

Pile shuffling your opponents deck at a competitive level may pose a problem. That does seem rather redundant. I would think it better for players to just pile shuffle their own decks and if need be just to do a quick "regular" shuffle of their opponents deck.

On the other hand, pile shuffling as part of the pre-game ritual is perfectly fine. It is not uncommon for the shuffling done between games to take a few minutes. You will often see players pile shuffling at a good speed to make it perfectly clear that they are not wasting any time to gain some sort of advantage.

Pile shuffling does not randomize a deck. Except during pregame, where pile shuffling allows players to count the number of cards in the deck, it might be considered a waste of time, and therefore considered slow play.

A waste of time is not the standard for why slow play is illegal. There are actual cards that do nothing else than shuffle your deck. Truly a waste of time but if you play these cards at a tournament no one is going to call a judge because of your miser cards.


I am terrible at expressing my thoughts in maths, but the idea with pile shuffling before or after randomisation is likely to be a way of proving that you're not attempting to cheat.

Even if you're able to remember a certain order of 60 cards, pile shuffling will rearrange the order of every single one of those 60 cards. Suppose you are able to memorise the order in which your 60 cards are at point A. Now perform a pile shuffle. You now need to shift the position of every single one of those 60 cards by x and remember the new order. Now perform another shuffling technique. Even if the second technique is not one that does sufficient randomisation either, you will still need to shift those 60 cards by another amount y on top of the shift by x. Now add a third method on top of that, shifting once again, now by amount z. I suppose it is possible to know the new order of the cards, but highly unlikely.

This does not even take into account what will happen if one of your 3 methods is actually one that DOES actually randomise the order of the cards instead of simply shifting them around.

This is what I feel is meant by the rules when they state sufficiently randomised. They don't have to be actually randomised, they simply have to be jumbled enough that it is unlikely that you still had significant influence over the order and position of the cards.

  • 1
    I don't agree with this answer. Remembering 60 cards is hard, but what if you only track one card? That's easy. It wouldn't take a genius to track a single card across fifty pile shuffles. As the rules say, if either player knows the location of a single card, the deck is not randomized (sufficiently or otherwise). Therefore, pile shuffling does not randomize the deck (sufficiently or otherwise).
    – Rainbolt
    Commented Mar 27, 2015 at 15:46
  • I was hoping it would illustrate my point that it increases the effectiveness of subsequent randomisation. Indeed it is possible to track a single card through pile shuffles, but all 60? Any method that will allow you to know the result of the shuffle assumes knowing the exact order in which all the cards are. By pile shuffling, this becomes exponentially more difficult.
    – Cronax
    Commented Mar 27, 2015 at 15:50
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    Mash shuffling is equally as effective if you know the starting locations of all sixty as it is if you know only one. Another way to state this is that knowing the starting locations of all sixty locations does not make mash shuffling less effective. A third way to write this is to simply point out that "If I know the starting locations of less cards, then the effectiveness of Mash Shuffling increases." is a non sequitur. I wrote it three different ways because I can't afford to continue another comment discussion. I'll leave the rest to voters.
    – Rainbolt
    Commented Mar 27, 2015 at 15:57
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    Here's one reason why pile shuffling is not randomization, even if a player does not remember the position of any of the cards: if a player has a 60 card deck with 20 lands (for simplicity), and before starting to shuffle, they put all of their lands on top, and then they do a 10 card pile shuffle, they will be guaranteed to have 2 lands every 6 cards. Even without knowing where any single card is, they know the layout of the deck. With a little math, someone could keep track of where all the lands are across an arbitrary number of pile shuffles.
    – murgatroid99
    Commented Mar 27, 2015 at 21:40
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    This is sort of true in that if you were going to inadequately shuffle, adding a random pile shuffle might well improve the randomization slightly. But the whole point is that you're supposed to shuffle adequately, so it doesn't matter.
    – Cascabel
    Commented Mar 28, 2015 at 1:03

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