Declumping a Deck

Jason Klaczynski is a well-respected member of the Pokémon TCG community who has been playing the game since its release in 1998. In addition to being a two-time World Champion and the winner of the Top Cut Invitational, he has an extensive history of writing Pokémon articles for

So, you’re playing at a Pokémon TCG tournament and your opponent plays a Pokémon Communication. He shows you a Cleffa, places it on top of his deck and begins searching for a Pokémon. As he searches, you see him spreading cards out in his deck, rearranging them.

“What are you doing?” you ask.
“Oh, I’m just declumping,” he explains.

Declumping? What is declumping? Well, the truth is, declumping is just a made up word that players use instead of stacking, which is a blatant form of cheating. Now, to be fair, declumping is done a little bit differently than stacking. When you attempt to cheat by stacking a deck, you typically are placing cards you want to draw on top of your deck in a certain order. Declumping is very similar in that players are placing their cards in a desired order, but not necessarily at the top of their deck.

Exactly what happens when a player declumps? One of the most common situations that results in a player declumping his deck is when he is searching his deck and notices several of the same card next to each other. It might be three Rare Candy; it might be five Energy Cards; it might be two, three or four Magnemites. In most turns of the game, you typically don’t want to draw into three consecutive Rare Candy or five consecutive Energy cards, and the player knows this, so his instinct is to spread those energies apart; that way, he will reduce the chance of drawing an unfavorable hand with a cluster of these cards.

So, why is this wrong? Well, the reality of randomness is that cards indeed can get paired next to cards with the same name. Sometimes five energy do get paired in a row. Sometimes three Rare Candy or three Junk Arm do end up right next to each other. Random doesn’t mean a perfect, even distribution. Random means every possible sequence of cards is equally possible – even those really ugly ones. A declumper may argue that they are further randomizing their deck by spreading these cards out – that three Rare Candy next to each other is not random – but this could not be further from the truth. You cannot artificially create randomness by moving cards to your liking.

However, there is one retort a declumper can use that does make sense. In fact, it makes a lot of sense! They can argue, “Well, if I’m shuffling my deck after I move these cards around anyway, what does it matter?” At this point, it’s important we realize that we are playing Pokémon in the real world.

When it comes down to it, the reality is that mid game shuffling in Pokémon isn’t exactly thorough, and, to be honest, I’m not sure that’s a bad thing. Two mathematicians, Persi Diaconis and Dave Bayer, wrote a famous paper about the amount of shuffling needed to randomize a deck. Their conclusion determined that five to seven riffle shuffles (with proper technique) were needed to randomize a deck. If you’ve played in a Pokémon TCG tournament before, I am sure you can attest that you and your opponent at some time in a game did less than 5 riffle shuffles after looking through the deck. Having to riffle your deck a minimum of five times can become time-consuming, especially for a novice player who is not only slow, but needs to shuffle more times to randomize his deck because of his poor shuffling form; that’s why I say that maybe it actually isn’t a bad thing that players don’t spend too much time shuffling mid game.

Unfortunately, humans are not shuffling machines.

But wait, how can I argue against declumping but then advocate not thoroughly shuffling your deck? It seems hypocritical, no? Well, this is why I said it’s important to remember Pokémon is played in the real world. If we expected thorough shuffles from every player after every search, a huge percentage of Pokémon TCG games would not be able to finish in the 30 minutes + three turns we are allowed. In the Pokémon TCG (and probably many other card games) there is an unwritten rule, or perhaps etiquette, to be forgiving of modest mid game shuffles because you trust your opponent is not manipulating or memorizing his deck.

Now wait, why did I mention “memorizing”? Well, when you look through your deck, whether or not you start moving cards around, the deck becomes unrandom. Just because you don’t start making your own sequences of cards by rearranging cards does not mean there are not some sequences of cards already in there that could be maintained by poor shuffling. Given that your deck is random when you begin searching it (assuming no effects changed this), if you simply play a search card and retrieve the card(s) it instructs you to, you cannot gain an unfair advantage by doing only a modest shuffle afterwards. The deck was random beforehand, you simply removed a few cards from it, and a few quick shuffles again leaves you with no way to know where any card is going to end up in correlation to any other card – as it should be. For the most part, Pokémon TCG players will be forgiving when you do a modest three to four riffles afterwards because it was obvious that you were not rearranging cards in an order to benefit you, nor were you trying to memorize what order your cards were in. Yes, technically you should do a few more shuffles, but, like I said, Pokémon is played in the real world, and you have to take a few things in the game with a grain of salt in order to keep the game friendly, fair and fun.

Some people who advocate declumping might insist that they do shuffle thoroughly, though! Let’s be real. If they thought they shuffled thoroughly enough to randomize the deck, why would they bother changing the order of cards before shuffling in the first place? Simply doing a sufficient shuffle would give all of those cards an equal chance of being next to any other card in the deck. Don’t let a declumper fool you; they move these cards apart because they expect their shuffling methods to not pair them back together as much as they should through natural probability. Needless to say, this is an unfair advantage. Even if this were the case, and your opponent really was shuffling sufficiently after each declumping, this simple rearranging of cards is at best going to be a waste of time. Some may argue that it wastes only a few seconds, but why even waste a few seconds? The mere act of rearranging cards that have nothing to do with the written instructions of your card is going to make any competitive player suspicious of your intentions and then cause them to waste additional time shuffling your deck after you do.

In addition, there is another retort I hear from people who declump their deck, but this one holds a lot less water than the previous one. One might say, “What does it matter if I am rearranging my deck? You are allowed to shuffle my deck anyway!” Well, in a nutshell, all this is saying is, “Yes, I am stacking my deck, but it doesn’t matter since you are allowed to undo it, anyway!” When it comes down to it, you have an obligation to play fairly; it is not my obligation to force you to. Just because I can shuffle your deck to thwart your attempt to gain an unfair advantage doesn’t mean what you are doing is fair or acceptable.

It is your obligation to play fairly.

Before we go any further, there are a few disclaimers I should throw out there.

1) It is not considered manipulative or cheating to move cards in your deck to help you make a decision a card instructs you to do. For example, when playing a Pokémon Collector, there is nothing wrong with moving your initial choices to the front of your deck as you prepare to select them. You are not trying to manipulate your deck to give you an unfair advantage; you simply are preparing your choice.

2) When I write regarding the unwritten rules of Pokémon that you shouldn’t memorize the order of your deck, that doesn’t mean you aren’t allowed a lengthy search. You absolutely are allowed to look through your deck to see if certain cards are prized. Judges typically allow more time for your first deck search than they do mid and late game. However, this is one of the situations where you should be expected to shuffle adequately afterwards.

3) Under current organized play rules, you cannot be penalized for declumping a deck. Well, why not? Michael Martin (otherwise known as PokePop), a well-respected veteran judge, explained the reasoning on the PokeGym forums:

“Just to note, it almost was made a part of the tournament rules that “declumping” would have been illegal. The sole reason argued against it and why it was not made against the rule was the difficulty in enforcement (‘I wasn’t declumping, I was moving a card that I was considering getting with my search and I changed my mind’).

So declumping is definitely not a good thing and while allowed (with sufficient randomization afterward), it is frowned upon.”

And he’s right – it is difficult to prove what someone is doing when he is rearranging cards in the deck.

So, the whole reason I wrote this article is to explain to you that even though you technically can declump your deck, you shouldn’t do it. At the end of the day, you are performing an action that is frowned upon by judges and players alike. The next time you are about to declump your deck, take a second to think about exactly what you are doing. Although it may not seem like a big deal, it impacts the game in more ways than one.


12 responses to “Declumping a Deck”

  1. Lukas Gindt

    Nice to see another article after such a long time. Even though your last one was about the history of the pokemon trading card game and not play itself ;). Great Job.

  2. Skyler Knopp

    Interesting and insightful, this was an enjoyable read. Thanks Jason!

  3. Anonymous

    A much larger problem for the community is cheating with your decklist. Deckchecks is an activity simply limited to the national champoionship – especially here in Europe. Bragging ’bout running 5 DCE’s in Luxchomp wasn’t rare back in the SP days, and I can’t really see it not being a case today. This has been an element bugging me excessively in my short time of competitive play, yet I can’t really do anything about it. The judges don’t seem to take this issue seriously, and keep on limiting deckchecks to topcut at nats. This isn’t just a moral problem – points are being stolen from us, “fair” players…

  4. Anonymous

    How sad is it that I actually own that shuffle machine? It was terrible.

    1. Skyler Knopp

      It really really was.

  5. Dylan

    Lol Josh, so do I….

  6. Jason P. Annichiarico

    Jason, I have one and only one question. When are you going to drop this topic? Also, what is your yearly income?

    1. DavidPenn

      You said only 1 question and you ask 2. Lol.

  7. Ross Gilbert

    Is it REALLY that bad? I’ve read this start to finish and…… meh.

    As long as it doesn’t waste time i have never complained about delcumping. I’m not going to do it regularly but i have done it now and again, never moreso than it’s been done against me.

    I don’t see the big deal. I’m not a huge fan of games where my opponent draws 7 energy in a row and that’s why i win. No fun that way.

    I’m all about the fun and if it makes it more fun….. 😀

  8. Anonymous

    I really don’t see the big deal about declumping. It seems like it would just save time shuffling, and I’d say slow playing is far worse.

  9. AM004

    This one was good and all, but bring on the Rotom Tricks article!

  10. The End

    declumping is definitely cheating, let me explain first I am guilty of this as well if you take a deck of playing cards you will notice that they have queen’s, king’s, jack’s, and numbers along with their suits (C.H.S.D) if you want you can arrange cards in the order that you want them to go just like in pokemon and fool the opponent by “randomizing” the cards by just riffle shuffling and 100% of the time always draw the perfect hand heres the example

    follow this pattern(playing cards)

    Clubs, Hearts, Spades, Diamonds

    then memorize what your placing for their suit and example

    8Cl,10He, KSp, KDi, KCl, KHe, 8Sp, 8Di, etc.

    with the rest of the deck no matter how much you shuffle your deck you will always have what you want and give people what you want them to have in pokemon you can even manipulate what’s in your prizes and where it is if you want them there

    only got caught once and that was when I was starting off and didn’t know as much, but now I’ve instead stopped and know the suddle moves that people use in tournaments, also used it on Magic players in my areas FNM whenever I wanted a quick buck
    so I leave you with that little tip that Declumping and having a cold deck are not so far apart if you know the moves…