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 some players but still beat the other players in the same round.
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.
The player's options for playing his or her hand are:
Hit: Take another card. signal: (hand held) scrape cards against table; (face up) touch finger to table
Stand: Take no more cards, also "stick" or "stay". signal: (hand held) slide cards under bet; (face up) move hand horizontally
Double down: Increase the wager to a maximum of double the original bet and take exactly one more card. For example, if the player's original bet was $25, the player could increase the bet by up to an additional $25, for a new total bet of up to $50. Increasing the wager to less than twice the original bet is called "double down for less". signal: place additional chips next to (not on top of) original bet, make "one finger" sign
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 rank. signal: place additional chips next to (not on top of) original bet, make "two fingers" sign
Surrender: Forfeit half the bet and give up the hand. signal: make 'chopping' motion over bet (signal is rare, usually just done verbally)
Hand signals are required in most casinos, so that in case of a dispute, a video record exists of the players decisions.
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.
Each Casino 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. Not all rules are posted. The player has to ask, either before-hand or when the situation occurs.
Dealer soft 17 In fact, there are two slightly different dealer strategies. In the "S17" game, dealer stands on all 17s. In the "H17" game, dealer hits on soft 17s; of course, he stands on hard 17s. (In either case, the dealer has no choice; he must or must not hit.) The H17 game is substantially less favorable to the player. Which game is customary depends on locality. Las Vegas Strip rules are about equally split.
Number of decks All things being equal, fewer decks are more favorable for the player. (This is true for basic strategy players, even without card counting.) In fact, all things are not equal; multi-deck games almost always have otherwise better rules than single-deck games.
Late surrender The player may "give up" and get back half his bet, before taking any other action. (In some places, this is posted, "surrender is available", while in other places, it is available, but it is not posted.) In some cases (15 vs. ten, 16 vs. 9, 16 vs. ace), this is slightly favorable. In one important case (16 vs. ten), it is definitely favorable.
Resplit to nn (In other words, the option to split exists for a two-card hand from a split the same as the first two cards.) The simplest rule is "resplit infinite"; this means that the player may continue to split so long as he receives same-value cards and is willing to put up the additional bet. More typically, the rule is "resplit to four." These rules are practically identical, since even four hands is fairly unusual.
Resplit aces In general, after splitting aces, the player gets only one card even with the above rule. With this rule in effect, an exception is made: if the second card is an ace, the player can resplit. (Of course, this is always favorable.)
Double after split In other words, the option exists to double for a two-card hand from a split the same as the first two cards. Generally, the player should play a hand after a split the same as the first two cards. However, this rule does slightly change which hands should be split in the first place.
Double on 10 or 11 only Often called "Reno" rules. (Also seen is "double on 9, 10, or 11 only".) It is annoying to many players because doubling soft hands is considered part of the game.
European no-hole-card rule The dealer does not receive a hole card. If the dealer is later found to have blackjack, the player loses his original bet and any additional bets (doubles or splits).
In some places, the dealer does not receive a hole card, but if the dealer is later found to have blackjack, the player loses only his original bet but not any additional bets (doubles or splits). This has the same advantage as the usual game and it should not be considered "European no-hole-card rule".
Altered payout for natural In some places, a natural pays 6:5 or even 1:1. This reduces or removes one of the main advantages for the player. Many players feel that this is tampering with a basic rule of the game.
Dealer wins ties This is catastrophic to the player. It is sometimes seen in "blackjack-like" games.
Five Card Charlie With this rule, the player always wins when five cards have been drawn without busting.
Insurance 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 because it, in effect, can protect the original bet if the dealer has a blackjack. If you bet the full half of the original bet, you win the same amount of the player's Blackjack wager. In this case, 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, and the insurance bet is forfeit.
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.