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Seven standard "riffle" shuffles are needed to effectively randomize a 52-card deck.
(lemmy.dbzer0.com)
this post was submitted on 01 Jan 2025
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I always thought riffle shuffles were super ineffective. Most of the cards remain in each others vicinity. What is a better way?
You're essentially splitting the deck and recombining the two halves imperfectly multiple times in a row. Like if a riffle was perfect, you would get the cards from both halves equally distributed, but nobody can do it perfectly, so they actually end up properly randomized. After 7 imperfect riffles, the entire deck is unpredictable.
After 4 perfect ABAB riffle shuffles, you would end up with the same order as you started with. If your shuffles are imperfect, your deck becomes more random every time.
I read ABAB as “Assigned Bitch at Birth” and immediately was like “hey that’s me”
I don't know much about card tricks, just that many appear to use non-random cuts and those ABAB shuffles to get cards where they need to go. This one 'The Hotel' might even be easy enough for me to learn:
https://youtu.be/P-6gCH1hRGs
It's the best way, period. Even as inefficient as it may seem, inexpertly done, seven shuffles and you're good.