Over one hundred variations in the rules exist, either because of local laws, or because of new ideas introduced by individual casinos. Variations effect how much of an edge the house has, so it is a good idea to know the local rules.
The player using basic strategy with a good knowledge of the rules can expect to lose less than 1 per cent of his or her bets, which is better than he or she could do with most casino games. Playing poorly because of ignorance can lead to greater losses. Below are a few of the most common variations.
On each blackjack table you can expect to see “S 17” or “H 17” printed. In the case of S 17, the dealer does not take a new card if he or she has 17 points, regardless of the cards that make up the 17 points. In the case of H 17, the dealer with 17 points stands except if one of his or her original cards is an ace. Two cards that add up to 17, including an ace, are termed a “soft 17.” Two cards not including an ace that add up to 17 are called a “hard 17”.
Number of decks
The fewer decks are involved, the easier it is for the player to keep track of what cards have been dealt. Also, the fewer decks there are, the fewer the types of cards that could still be dealt after the first deal. When only one deck is used, the casino generally uses other rules in its own favor.
Double decks are better for the player than quadruple decks, which are better than six. After six, there is little difference. If a player is dealt an ace with a single deck, there are only 3 more aces available, decreasing the probability of the dealer’s having an ace in the hole. If there are 6 decks, then there are still 23 more aces that might be in the dealer’s hand.
Some casinos offer players to give up half their bets and not play out whole hands, after the dealer has checked his or her hole card in the USA. In some countries, casinos offer “early surrender,” in which a player may surrender his ro her hand before the dealer checks his or her hidden card.
A player may split a pair. If he or she is then dealt a card of the same value, (except if the cards are aces) the player may re split, putting down another bet equal to the first two for the third hand. Some houses allow any number of splits, while others limit the number of re splits.
Hit/Re split Aces
Rare houses will allow re splitting aces. Usually when that is allowed, only one more card will be dealt to each hand, and doubling down is not allowed.
After he or she is dealt two cards, the player may double down, or double his or her initial bet and request only one more card. Additional chips are placed next to the original bet to signal the desire to double down.
The Reno Rule
This rule restricts players to doubling down only with an initial total of 9, 10, or 11, or just 10 and 11. This increases the house advantage since players are not allowed to double on hands such as soft 17.
No Hole Card
Outside the USA, no-hole-card games are played. The dealer in such a game does not draw or consult his hole card until after the players have made their decisions. In this kind of game it is not a good idea to double or split against a dealer’s 10 or ace, since a dealer blackjack will cause the loss of split and double bets, unless a pair of aces is played against a dealer’s 10. Then it is still okay to split. In some casinos, if the dealer later turns out to have blackjack, the layer loses his original bet but not any doubles or splits.
Altered Payout for Blackjack
Sometimes when only one deck is being used, blackjack will only pay 5:6 or 1:1 instead of the usual 3:5, since the player has the advantage of being able to count with only one deck.
Dealer Wins Ties
This variation so favors the house that it is usually only played in charity games.
If the dealer’s known card is an ace, the player has the option of betting that the dealer will get blackjack. This bet is half the player’s original bet, and pays 2:1. Insurance is not a good idea unless the player is counting cards, because the probability that the dealer will get a 10 card is only 4/13. If the player is counting cards and knows that the probability is higher, insurance can be a wise decision.
Some houses allow players to make bets alongside their original bets,and such bets include getting three of a kind, a pair, or many others.