The curious case of the unshuffled decks of cards

Tikay10

There was a delicious article in Cardplayer recently, later picked up on 2+2, of a "Live" casino in Philadelphia where the deck of cards went unshuffled for 16 hands in a poker tourney before anyone noticed.

In fact it was better than that. The cards were, in effect, a brand new unshuffled deck each time. You know how a new deck of cards looks, all nicely arranged in suits & ranking;





They were using an auto-shuffler - one of these;




If you've never seen one of those operate, it goes like this. It contains 2 decks of cards. The dealer presses a button & the lid opens, dealer removes one deck then closes the lid. Dealer then cuts the deck. (This is crucial).

The hand is then dealt normally, once it is over, dealer scoops up all the cards, presses a button to open the auto-shuffler lid & places the used deck inside, then takes the 2nd deck from the auto-shuffler, closes the lid, presses a button to start the automatic shuffle, then cuts the new deck & deals.

The auto-shuffler, rather oddly, has TWO settings. One is to shuffle, the other is to sort. And "sort" means like this......





Unfortunately, the auto-shuffler had accidentally been set to "sort"......

Tikay10

Now it gets (arguably) interesting.

As the auto-shuffler had been set to "sort", the cards ALWAYS came out in the same order, except for two variables – where the dealer cut the deck (which can often be similar, around halfway perhaps) & the button moving every hand.

So a typical deal might look like this, I think;


Player A (Small blind) 9c 4d

Player B 10c 5d

Player C Jc 6d

Player D Qc 7d

Player E Kc 8d

Player F Ad 9d

Player G 2d 10d

Player H (button) 3d Jd

Flop & board would now come (allowing for burn cards)….

Kd As 2s

Turn

Kd As 2s 4s

River

Kd As 2s 4s 6s

Tikay10

One thing which is odd is that a typical board might very well appear like this…..


4h 5h 6h 8h 10h


And yet nobody noticed for 16 consecutive hands.

And unless I’m reading it wrong, not one player got dealt a pocket pair for 16 consecutive hands.

Of course, if you KNEW the deck was coming out unsorted every hand, & nobody else did, it was very exploitable.

Anyway, in the hand I have shown above, bearing in mind you all KNOW what the board is going to be, what hand would you most wish to have?

Tikay10

Incidentally, the Casino was fined $100,000 for this & a few other anomalies & irregularities.

TommyD

That's crazy that no one noticed. If I noticed just give me any ace to luckbox a flush early while I try to work out the math at the table to work out what's coming where.

Incidentally, this reminded of this from QI https://youtube.com/watch?v=SLIvwtIuC3Y


To save those at work with a click, it's the math of the 52 factorial that states it is nearly impossible that any shuffled deck has been in that exact order before, ever.

Maths is big.

SidV79

Tikay10 said:

One thing which is odd is that a typical board might very well appear like this…..


4h 5h 6h 8h 10h


And yet nobody noticed for 16 consecutive hands.

And unless I’m reading it wrong, not one player got dealt a pocket pair for 16 consecutive hands.

Of course, if you KNEW the deck was coming out unsorted every hand, & nobody else did, it was very exploitable.

Anyway, in the hand I have shown above, bearing in mind you all KNOW what the board is going to be, what hand would you most wish to have?

7s Ah in the cut off

goldnballz

Very interesting!

Mind boggling video that

Tikay10

Type your comment

TommyD said:

T

Maths is big.

Ali G asked what was the biggest number in the world, & was told "infinity".

He retorted "how about infinity plus1?"

Phantom66

Ideally you want 2h3h but seeing as how it as an unsorted deck you can only hope to have the Ah for the nut flush.

Tikay10

Phantom66 said:

Ideally you want 2h3h but seeing as how it as an unsorted deck you can only hope to have the Ah for the nut flush.

Our problem is that in this situation it is impossible to be dealt suited connectors. It's also impossible to be dealt a pocket pair.

Phantom66

I bet they would have spotted it sooner had it been Omaha

Tikay10

Phantom66 said:

I bet they would have spotted it sooner had it been Omaha

You may be right, but I can't figure out why. Very hard for the players to get dealt suited rundowns, or even any rundowns, both of which are what Omaha players want to be dealt.

Phantom66

I just thought with 4 cards there is more chance of seeing the pattern in your own hole cards and I doubt there would be much action which would be suspicious.

Tikay10

Phantom66 said:

I just thought with 4 cards there is more chance of seeing the pattern in your own hole cards and I doubt there would be much action which would be suspicious.

Morning @Phantom66

I could not quite grasp why this was so last night, but I think I get it now, & yes, you were correct.

If we continue with the hand shown near the top of the thread, but extend it to Omaha, here are the hands dealt, & the Board;

Player A (Small blind) 9c 4d Qd 7s

Player B 10c 5d Kd 8s

Player C Jc 6d As 9s

Player D Qc 7d 2s 10s

Player E Kc 8d 3s Js

Player F Ad 9d 4s Qs

Player G 2d 10d 5s Ks

Player H (button) 3d Jd 6s Ah

Board (allowing for burn cards)

3h 4h 5h 7h 9h


There are a couple of playable hands there – certainly the 2 players holding suited aces & paint – but I think you are right – at this point, the players would surely realise something is amiss by the texture of the board cards.

Incidentally, at first sight, if all 8 players saw this flop, none of them would flop much except player H, & as he held the Ah, I guess he could play the bare ace thing & take it down. (I think the bare ace thing in Omaha went out of fashion about 15 years ago - these days you'd get called with ANY flush).

SidV79

Phantom66 said:

Ideally you want 2h3h but seeing as how it as an unsorted deck you can only hope to have the Ah for the nut flush.

I thought the same but the 3h gets burned before the flop is dealt