If card counting in blackjack is just keeping track of high cards vs low, does that mean if I could remember all the different cards used (i.e. how many 5s, how many 7s) I would be really good at blackjack?

Question

This would break online casinos because you could easily do that with electronics. Assuming the casino itself is playing fair.

If you could perfectly keep track of how many of which cards are left in the decks, and everytime make the most mathematically sound bet, would the house still have an edge?

(I assume the correct answer will start off saying I don’t understand how card counting works – fair enough, but what about the basic explanation of it did I misinterpret?)

In: Mathematics

Answer 1

Yes. In card counting you assign a value to each card played. (Simple strategy is 2-6 is +1, 7-9 is 0, 10s/Ace is a -1) 

 then higher current totals means getting played a higher value card is more likely and getting blackjack more probable. Computers would do this much better.  

 Its not a sure win but you improve the margins of winning. (General best-strategy blackjack has a return of 97.5%, with counting it can increase to 102.5%. So a loss into a profit)  

 Casinos counter this with using multiple decks and shuffling them frequently. With 4 decks the odds average out again. It doesn’t matter how good you are at counting, there’s just too many cards in play to make a difference. 

Then shuffling frequently makes any advantage very short term. You can’t get a good enough picture of the cards left before they shuffle again. 

 Also, they’ll just ban you. Casinos don’t like to lose money.