What is CDZ (Card Distribution Zone)?

CDZ (Card Distribution Zone) is a concept referring to the portion of the shoe from which cards have been dealt. In multi-deck blackjack, the composition of remaining cards in the shoe directly affects the EV of every action.

Blackjack Counting Calculator tracks the exact card counts seen so far and computes EV based on the remaining composition. This is more accurate than generic basic strategy tables, which assume a full shoe. As cards are removed, the optimal play for certain hands can change — for example, the threshold for doubling down or taking insurance may shift.

Understanding CDZ helps explain why Blackjack Counting Calculator's recommendations may sometimes differ from a printed basic strategy card: Blackjack Counting Calculator is responding to the specific shoe state you have observed, not a theoretical average shoe.