Casinos started using multiple decks in a blackjack game to keep card counters from winning, but this move didn’t deter them as they translated their running count to a “True Count.” The true count or count per deck is a way to keep track of the cards remaining per deck.
A running count of +5 with six decks remaining means that there is still less than one high card remaining per deck, so the player doesn’t have an advantage yet. When there are multiple decks in play, the number of high cards remaining isn’t the only thing to look out for, but also the concentration of such cards compared to low ones.
A running count of +5 with one deck remaining means there are five extra 10’s and Aces remaining in the deck, giving the player an advantage over the house.
Gamblers can determine the true count by dividing the running count by the number of decks remaining. If the running count is +10 and five decks still remain, the true count is 2.
Using both basic strategy and card counting lets gamblers place good bets to ensure that they can win against the casino. The true count informs people how to change their playing strategy.