Last time I had lots of theoretical questions. This time I have a single, completely practical one.
My understanding has long been that the only acceptable way to shuffle at a CCG tournament is the riffle shuffle. Pile shuffling doesn’t randomize the deck, so it’s useful for checking to make sure a deck has the correct number of cards but is otherwise unhelpful. Side-shuffling (a.k.a. slide-shuffling, mash-shuffling, etc.) allows sleeved cards to stick together and stay together, knifing through the unstuck cards and coming out of the process still grouped. Riffle shuffling randomizes the deck and breaks up clumps, so–so far as I knew–it was the best, and indeed only really acceptable, option.
As a result, I was surprised by this video, which I saw linked on ChannelFireball:
The video demonstrates a side-shuffling technique wherein the cards are held off to one side, so that the player shuffling cannot possibly see the cards.
I understand the value in making sure that people aren’t sneaking peeks while shuffling, but I would be much more concerned about the possibility of an insufficiently randomized deck than I would be about my opponent potentially seeing a card, even an important card. As a result, I feel like I would much rather the opponent be riffle shuffling.
Has the received wisdom on this topic changed?
The Law of Game Design 
Not sure what exactly the judge’s rules are, though I’d expect them to be on the look-out for intentionally-poor shuffling.
It’s impossible to state an objective truth about a shuffling technique being good enough or not. In particular, a single twist or combination throws any statistics off entirely.
For example, I cut the top quarter of my deck to the bottom before riffle-shuffling, and that completely changes the result. If you were to riffle-shuffle and side-shuffle your deck once each, that would likely provide a more random result than doing one or the other twice.
Ultimately, this is why you always shuffle your opponent’s deck after she does.
If people want to really statistically serious about shuffling, they should just use shuffling machines. I hear they use them in Las-Vegas (:
Something for the store to provide, in addition to lands! 🙂