When reading a blackjack strategy chart, it is important to have an understanding of the different types of charts that are available. There are traditional strategy charts that show the theoretical probabilities of each outcome and there are betting charts that show the actual money that has been wagered on each possible outcome.
The traditional strategy charts will typically use a horizontal or vertical line to indicate the theoretical chances of hitting a specific number, such as 21. A bet placed on this number will result in a payoff if the player hits the number, regardless of what other numbers are drawn.
A betting chart, on the other hand, will show which numbers have been wagered on and which numbers have been hit. This can be helpful in determining whether or not to place a bet on certain numbers, as well as in determining which numbers to avoid.