If you can tell the difference, then by definition you didn't shuffle well. A mana-woven deck that you don't shuffle properly is going to seem more like a well shuffled deck because it plays nicely and doesn't give you obviously repeated stuff all in a row. A clumped deck that gives you tell-tale all-land or no-land streaks is frustrating to play, so you're more likely to realize you've done something wrong. But both decks are improperly shuffled, and could get you in trouble at a tournament.

Yes, both beginning states (land woven or clumpy) could be considered manipulating the deck. But if you're actually shuffling properly, so that any card has equal probability of ending up in any position in the deck when you're finished, the starting state is completely obliterated and doesn't matter. And it doesn't take thirty shuffles. Seven or eight should be plenty to fully randomize a sixty card deck, assuming a well-performed riffle or mash-together-edgewise-with-sleeves)

Riffling is terrible for your cards.
Going back to the source of all this, I don't care if an opponent shuffles my deck afterwards. It's specifically if they try to riffle shuffle that makes me mad. Mash shuffling doesn't bother me.

Exactly. But what the pro-weave arguers fail to understand is that even a completely-randomized-shuffled-deck will have streaks. There will be clumps of 4 lands in a row or 6 nonlands in a row, because that's how randomness (not uniformity) works. They won't be there because they stayed clumped from their pre-randomized state, but because they happened to end up together as a result of the shuffle. And that's what seed-shuffling is negating - by starting with a streakless state and shuffling less than enough to truly randomize, the end result is a more-streakless deck than a full randomization would be.

More streakless != more random. Quite the opposite. If your shuffle would have been inadequate to remove the streaks from the initial state of 36 nonlands then 24 lands, the exact same shuffle is inadequate to remove the seeded-streakless-bunches you deliberately planted in your deck pre-shuffle. The second state isn't more random just because it's more favorable.

Some do. I dislike the practice, because it looks like it legitimizes pile shuffling. When I count my deck, I count it out into piles of ten, one pile at a time. It makes it obvious I am counting and not actually pile shuffling.

I feel like I should make a video of myself riffle shuffling an unsleeved deck, because people talk tons about how it bends cards and in nearly twenty years of playing this game I have yet to see damage accrued from how I shuffle. Is my method some bizarre non-damaging riffle-like shuffle? Are they just talking about fools who do the vegas-style high bridge that does absolutely bend cards? Seriously, my observed experience is not matching up with the data I get from the magic-playing community.

If a deck is sleeved, though, I mash it. Mash shuffling as I know it. is impossible with unsleeved cards (THAT is guaranteed to mess everything up), but riffling as I know it is virtually impossible with sleeved cards. while mashing is similar and easy.

Full sentences help get your idea across. Why what? Why am I fixated with the number 3? Heck if I know. Maybe I'm OCD.

there's actual math papers covering this topic out there, many of which are behind paywalls/registration walls so i am not linking to any of them, but the well-known formula is k = 3/2 log2 n, where n is the size of the deck and k is the approximate number of riffle shuffles needed to randomize the deck sufficiently

basically, it takes 3/2 log2 60 = 9 riffle shuffles to sufficiently randomize a 60 card deck (the answer is actually 8.86 something, but i want to see someone shuffle a deck 0.86... times and tell me how that works out), and similarly 10 riffle shuffles to sufficiently randomize a commander deck and 8 riffle shuffles for a 40-card limited deck

How do you know if your opponent's been mana weaving?

In the case where I taught a new player that was cheating and mathematically why, you see them do it between games, right in front of you.

This is very true. Randomness is, by nature, lumpy. But we human beings are *terrible* judges of randomness, and we mistakenly equate even distributions with random ones.

I had a friend in gradutate school who did research in this area, and he had an experiment he always liked to do with the undergrad psychology students. He would ask everyone in the class he was TA'ing to write down the outcomes of 200 coin flips, either by actually flipping a coin 200 times, or by faking the results, but without telling him which. The next day, he would collect the papers, and, by the end of the class, he would have sorted them into piles -- real outcomes, fake outcomes -- and he was right the overwhelming majority of the time.

I asked him how he did it. and he told me that he literally did one thing, and one thing only -- he checked each sequence to see if it contained a run of either 7 heads in a row, or 7 tails in a row. If it did, the sequence was probably real. If it didn't, it was probably fake.

Flip a coin 200 times, and you're likely to get at least one run of 7 heads or tails in a row. But, ask a human being to fake 200 "random" coin flips, and they won't make streaks that long, because we think that such streaks look too "non-random."


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@ Grifter -- Your points in response to mine were all totally reasonable, and I'm happy to stand corrected.

With that being said, it still bugs me when people shuffle my deck. I'll concede that I don't have a rational basis for feeling that way, but it does bug me.

That's on me, I guess.

Oh yeah, my High School Physics professor did that too. Only we had to make up one, then actually flip a coin, and present both to our teacher. I made sure to have a sequence of at least 9 in our made up one, but the teacher still figured it out. Faking random is tough man.

I quoted the whole thing, so a reasonable assumption could be that I was talking about the whole thing.

specifically, why do you have a complex, multi-step process (one that ends by not shuffling nearly enough, by the way) instead of just picking up all your cards at once and skipping straight to step 4, the only step that actually does anything? as has been said repeatedly, either you're wasting time or you're cheating, so why do it?

Concur.

I've been playing magic since The Dark, sleeveless and riffle shuffle (but I do use a low bridge) and I have yet to see shuffle based damage. Play wear, yes; shuffle bending, no. Though the few people trying to perform a mash shuffle on unsleeved cards have damaged at least one card every time.

I will concede that I also had over a decade of Riffle Shuffle experience before starting magic (Pinochle and Euchre growing up) and adapting to the thickness of a magic card was not difficult (double Pinochle decks fresh from the box...that's difficult). Also, if it matters, I only play casual.

The agreement I make when I play a new opponent is "I won't riffle shuffle your sleeved cards, if you don't mash shuffle my unsleeved ones."

And I weave my decks when they are first built.

Mana weaving isn't wasting time if it maless you feel better about your deck. Morale is important.

I answered this already, sort of.

Did you miss the post I made about running 3 of every nonland card?


I offered a possibility that could explain this.

Wrong. Proper randomness does not depend on the initial state. You are thinking about a deck state that would give you a keepable hand, not about a randomized deck.

We had a looong discussion about the shuffler and randomness on the defunct forums. So:

A proper shuffle is a shuffle that ensures that the shuffled state has no relation to the state before you started shuffling.

But there is no such thing in paper. What you should aim for is:

A proper shuffle is a shuffle that makes it reasonably probable that the shuffled state has little or no relation to the state before you started shuffling.

Therefore, if you shuffle properly, it just doesn't matter how you picked up your cards after the game. But this is counter-intuitive. You tend to think that land clumps won't redistribute, or some similar things. But it's a fact that, if you know how to riffle, you put all the lands on the bottom, and in a few riffle shuffles you get to a mana-weaved deck. Also, a random distribution means there will be mana clumps.

You see that digression? See it?! That's exactly what I don't want to have to deal with in the middle of a match.

It's a fairly common feeling, no doubt--you're probably in very good company. Opponents shuffling your deck is after all an anti-cheating safeguard at heart, and having those kinds of things enforced tends to feel like an accusation.

Can I bring handsanitizer and make my opponent clean their hands before touching my cards?

With the exception of Ancient Tomb, I think the Expedition lands look inferior to their original counterparts. I like Tomb because it reminds me of Dragonstone, from Game of Thrones. And being I play Dragon Stompy...yes.

Oh come on, the expedition Godless Shrine is the bee's knees!