The basic blackjack strategy revolves around whether a player should hit or stand or exercise the option of double down or split. The strategy depends on the player’s existing hand value, the dealer’s open card and the number of packs being used and also on the variations to the rules as applicable to the casino. It is impossible to manually calculate the probabilities associated with the various options because of the uncertainties of which cards will be dealt next. However computer software has been used to simulate the outcomes over a large number of games and basic strategies have been formulated. The basic strategy is represented in the form of tables, with separate tables for the different variations in rules and for the number of packs used. The rows indicate the players hand value and the columns the dealer’s open card. The cell corresponding to a row and column indicates the option the player should exercise.
The basic strategy assumes that all cards have equal probabilities of being drawn. However this is not the case. The cards that have been dealt are out of play till the decks are shuffled again. It may so happen that more small value cards are out of play and more high value cards are left in the deck. In that event the basic strategy will have to be suitably modified. If the there are more high value cards left then the chance of the player winning increases and players tend to place larger wagers. In order to assess the nature of cards left in the deck a number of card counting strategies are prevalent.
The plus minus count system is the simplest. Twos to sixes are assigned a value of +1 each and ten value cards are assigned a value of -1 each. All other cards are assigned a value of zero. As the cards are dealt or opened their assigned values are accumulated. The more positive the accumulated total, the greater the number of low value cards that are out of play and therefore the greater the number of high value cards that are left. Hence a more positive accumulated total is favorable for the player. The plus minus count system can be easily implemented in the fast pace of the game. Other systems, though more accurate, are difficult to implement.
Casinos do not like card counting because it increases the player’s edge. Casinos counter card counting using a variety of means. The most common one is to increase the frequency of shuffling.