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Comment by travisjungroth | Hacker News Reader

Sort the cards into suit piles. Turn them face down. Shuffle the suit piles until you don't know which is which (maybe challenging). Take off 1, 3, 3, and 5 cards from piles. You'll have the deck as described.

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Shuffling piles is difficult to do in a way that nobody, including the dealer, knows which is which. And it requires more table space. It also requires an additional shuffle of the final deck. If the final shuffle is not good enough you can guess which one was the short suit by looking at the sequence of the dealt cards (the deck was not cut, and the last 2 cards are the same suit? chances are the dealer is bad at shuffling and it's the short suit). Maybe passing a tray with four piles and letting each player to swap two piles without letting other players see which piles were swapped is good enough. But it's still fiddly.

Normal shuffle and discarding face down is easier to explain and faster to do. And it can be done where the table is not available or is not big enough. Starting with a 44-card deck and discarding 5 down to 39 should make it more similar to the original 40-card version, but 39 is not divisible neither by 5 nor by 4, so one player will always be one card short.

Being one card short might not actually be a problem in practice if the game is played across several rounds. It may even add some interest to the game by creating an asymmetry.

I love how detailed this is but the engineering problem has been solved with card shuffle machines. You can buy one on Amazon for $20. Put the cards face down and hit shuffle (repeat a few times).

I think you can assume decent shuffling for the sake of the problem. And with cards dealt around, you don’t see two cards in a row. You’d have to be pretty bad to get usable info from cards at position n and n+4 being the same suit.

edit: People can be pretty bad at shuffling though. Overhand shuffles are awful and info would be available. But I think this game naturally sorts the cards pretty well by the end of gameplay, so even the method proposed before me would be vulnerable to info from bad shuffles.

Two player blind shuffle. All players except one turns away. Remaining player shuffles. All players except a different one turns away. Remaining player shuffles. Now no one knows which pile is which.

> All players except one turns away.

A bit trusting!

Assuming at least 3 players, only have 1 player turn away during each round of shuffling.

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