Online blackjack variants are popular at Internet casinos because they offer average returns that are very close to 100%. This comes with a catch. In order to achieve these returns players have to wager using optimum strategy. Optimum strategy involves choosing the correct blackjack move from those available. Players who do not use the optimum strategy can end up with extremely low average returns.
The problem with optimum blackjack strategy is that it cannot be logically reasoned out while playing at the online casino. In order to arrive at the optimum strategy an extremely large number of deals have to be simulated on the computer. The strategy so arrived at has to be known to the player. Memorizing this strategy is not convenient and it can lead to errors. Therefore software providers have devised a blackjack strategy card that displays the optimum strategy in an easy to read manner.

The two factors that critically impact optimum blackjack strategy are the value of the player’s current hand and the dealer’s face up card. The strategy card indexes the optimum move with reference to these two factors. There are other factors that also determine optimum blackjack strategy such as the number of decks used in the game and whether or not the dealer is allowed to hit on a total of soft 17. It is not convenient to include each and every factor in the strategy card. Also the other factors remain unchanged for a given online blackjack variant. Therefore software providers usually include a separate strategy card for each blackjack variant that has been specially developed for that variant.
The blackjack strategy card has a tabular structure. The columns of the table indicate the dealer’s face up card. The rows of the table indicate the player’s current hand value. The cell at the intersection of a given column and row indicates the optimum move to be made when the conditions of that row and column are met. When the dealer’s face up card is a four and the player holds a seven and a six, having a hand value of 13, the corresponding cell on the strategy card will say “stand”. The full move name cannot be fitted into the strategy card. Therefore codes have to be used. The blackjack strategy card is double coded for safety. It uses the letter S for “stand” and the letter H for “hit” and so on. Also, the cell may have a yellow background for “stand” and a red background for “hit” and so on. The codes used will be explained at the bottom of the strategy card. Land casinos do not allow players to take strategy cards with them. However there is no such restriction while playing blackjack at online casinos. In fact the best software providers include these strategy cards along with their blackjack variants. If the card has not been made available with the game, players can download it from various online blackjack sites on the Internet.

The best software providers have gone one step ahead as far as the use of the blackjack strategy card is concerned. It is inconvenient to toggle between the main game screen and the strategy card before making every move. Therefore software providers allow blackjack games to be played on auto play, with the software ensuring that the optimum moves are selected each time.