The hand with the highest total wins as long as it doesn't exceed 21; a hand with a higher total than 21 is said to bust or have too many. Cards 2 through 10 are worth their face value, and face cards (jack, queen, king) are also worth 10. An ace's value is 11 unless this would cause the player to bust, in which case it is worth 1. A hand in which an ace's value is counted as 11 is called a soft hand, because it cannot be busted if the player draws another card.
Each player's goal is to beat the dealer by having the higher, unbusted hand. Note that if the player busts he loses, even if the dealer also busts. If both the player and the dealer have the same point value, it is called a "push", and neither player nor dealer wins the hand. Each player has an independent game with the dealer, so it is possible for the dealer to lose to one player but still beat the other players in the same round.
The minimum bet is printed on a sign on the table and varies from casino to casino and table to table. After initial bets are placed, the dealer deals the cards, either from one or two hand-held decks of cards, known as a "pitch" game, or more commonly from a shoe containing four or more decks. The dealer gives two cards to each player including himself. One of the dealer's two cards is face-up so all the players can see it, and the other is face down. (The face-down card is known as the "hole card". In European blackjack, the hole card is not actually dealt until the players all play their hands.) The cards are dealt face up from a shoe, or face down if it is a pitch game.
In American blackjack, if the dealer's face-up card is an ace or a ten-value, the dealer checks his hole card to see if he has blackjack. This check occurs before any of the players play, but after they have been offered insurance (if the face-up card is an ace). If the dealer has blackjack, all players lose their initial bets, except players who also have blackjack, who push. (In some American casinos, the dealer does not actually check the hole card until after the players have all played. At that time, if the dealer turns out to have blackjack, all players who did not have blackjack lose their bets, and players who increased their bets by doubling or splitting lose only the original bet, and have the additional bets returned to them; thus, the end result is precisely as if the dealer had checked the hole card before playing.)
A two-card hand of 21 (an ace plus a ten-value card) is called a "blackjack" or a "natural", and is an automatic winner (unless the dealer has blackjack as well, in which case the hand is a push). A player with a natural is usually paid 3:2 on his bet. Some casinos pay only 6:5 on blackjacks; although this reduced payout has generally been restricted to single-deck games (Current Blackjack News, Pi Yee Press). This reduced payout for a natural increases the house advantage over a player by as much as 1000 percent. The move was decried by longtime blackjack players.
The player's options for playing his or her hand are:
* Hit: Take another card.
* Stand: Take no more cards.
* Double down: Double the wager, take exactly one more card, and then stand.
* Split: Double the wager and have each card be the first card in a new hand. This option is available only when both cards have the same value.
* Surrender: Forfeit half the bet and give up the hand. Surrender was common during the early- and mid-20th century, but is no longer offered at most casinos.
The player's turn is over after deciding to stand, doubling down to take a single card, or busting. If the player busts, he or she loses the bet even if the dealer goes on to bust.
After all the players have finished making their decisions, the dealer then reveals his or her hidden hole card and plays the hand. House rules say that the dealer must hit until he or she has at least 17, regardless of what the players have. In some casinos a dealer must also hit a soft 17 (a combination of cards adding up to either 7 or 17, such as an ace and a 6).
If the dealer busts then all remaining players win. Bets are normally paid out at the odds of 1:1. Players who push (tie) with the dealer receive their original bet back.
Some common rules variations include:
* Only one card for split Aces: a single new card is added to each Ace and the turn ends. They are thus regarded as 11-point cards. No other denomination is subject to this process.
* Multiple splits: If a player splits 2 cards and receives a third card of identical value, the hand can be split again, resulting in 3 hands. However, some casinos only allow a single split of the first 2 cards.
* Early surrender: Player has the option to surrender before dealer checks for Blackjack.
* Late surrender: Player has the option to surrender after dealer checks for Blackjack.
* Double-down restrictions: Double-down may only be allowed on certain combinations of cards (usually totaling 9, 10 or 11).
* Double-down after split: Double-down may not be allowed after splitting cards. The split hands are played normally otherwise.
* Split any tens: Players may split any 2 cards which are both worth 10 points, such as a Jack and Queen. This rule is rarely used, since 20 is a very strong hand which is unlikely to be split.
* European No-Hole-Card Rule: the dealer receives only one card, dealt face-up, and does not receive a second card (and thus does not check for blackjack) until players have acted. This means players lose not only their original bet, but also any additional money invested from splitting and doubling down. A game that has no-hole-card doesn't necessarily mean the player will lose additional bets as well as original bets. In some Australian casinos for example, a player beaten by a dealer blackjack may keep all split and double bets and lose only the original bet, thus the game plays the same as it would if there were a hole card.
Each blackjack variation has its own set of rules, strategies and odds. It is advised to take a look at the rules of the specific variation before playing. Many countries have legal acts and laws, which determine how a casino game of Blackjack must be played. Over 100 variations exist.
If the dealer's upcard is an Ace, the player is offered the option of taking Insurance before the dealer checks his 'hole card'.
The player who wishes to take Insurance can bet an amount up to half his original bet. The Insurance bet is placed separately on a special portion of the table, which usually carries the words "Insurance Pays 2:1". The player who is taking Insurance is betting that the dealer was dealt a natural, i.e. a two-card 21 (a blackjack), and this bet by the player pays off 2:1 if it wins. It is called insurance since if the dealer has a blackjack, the bet wins the same amount of the player's Blackjack wager, such that if insurance is taken and the player doesn't have blackjack but dealer does, no money is lost. Of course the dealer can end up not having blackjack and the player can still win or lose the blackjack bet.
Insurance is a bad bet for the non-counting player who has no knowledge of the hole card because it has a house edge of 2 to 15%, depending on number of decks used and visible 10-cards . Essentially, taking insurance amounts to betting that the dealer's hole card is a ten or face card. Since in an infinite deck, 4/13 of the cards are tens or face cards, an unbiased insurance wager would actually pay 9:4, or 2.25:1; since the bet only pays 2:1, the house has a strong advantage. However, if the player has been counting cards, he may know that more than a third of the deck is ten-value cards, in which case insurance becomes a good bet.
If a player has a natural (an ace and a ten or face-card) and the dealer is showing an ace, the dealer usually asks the player "Even money?" instead of offering insurance. If the player accepts the offer, he is immediately paid 1:1 for his natural, regardless of whether the dealer has blackjack. Thus, accepting "even money" has exactly the same payout as buying insurance: if the dealer does not have blackjack, the player would forfeit the insurance bet and win 3:2 on the natural, thus receiving a net payout equal to the original bet; if the dealer does have blackjack, the player would push on the natural and win 2:1 on the insurance wager, again receiving a net payout equal to the original bet. Since taking "even money" is equivalent to buying insurance, it is likewise a bad choice for the player, unless he has been counting cards and knows the deck has an unusually high proportion of ten-value cards.
In casinos where a hole card is dealt, a dealer who is showing a card with a value of Ace or 10 may slide the corner of his or her facedown card over a small mirror or electronic sensor on the tabletop in order to check whether he has a natural. This practice minimizes the risk of inadvertently revealing the hole card, which would give the sharp-eyed player a considerable advantage.