The number of decks has an impact on card counting and the house edge. Wouldn't it be great if just 1 deck of cards was used in a game of blackjack? It would be so easy to employ blackjack card counting techniques and eliminate much of the house edge in the process.Īs fate would have it, casinos typically feature 6 to 8 decks of cards in blackjack games. NUMBER CARDS AND PICTURE CARDS IN BLACKJACK WHY IS AN ACE VALUED AT 1 OR 11 IN BLACKJACK?.NUMBER CARDS AND PICTURE CARDS IN BLACKJACK.