Hit, Stand or Double Down
Blackjack's precursor was "twenty-one", which originated in French casinos around 1700, and did not offer the 3:2 bonus for a two-card 21.
When 21 was first introduced in the United States it was not very popular, so gambling houses tried offering various bonus payouts to get the players to the tables. One such bonus was a 10-to-1 payout if the player's hand consisted of the ace of spades and a black Jack (either the Jack of clubs or the Jack of spades). This hand was called a "blackjack" and the name stuck to the game even though the bonus payout was soon abolished. As the game is currently played, a "blackjack" may not necessarily contain a jack or any black cards at all.
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 too many. Cards 2 through 10 are worth their face value, and face cards (jack, queen, king) are all 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 they lose, 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.
The minimum/maximum 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 blackjack, if the dealer's face-up card is an ace or a ten-value, the dealer checks their hole card to see if they have a 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.
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. 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.
signal: (handheld) scrape cards against table; (face up) touch finger to table
- Stand: Take no more cards, also "stick" or "stay".
signal: (handheld) slide cards under bet; (face up) move hand horizontally
- Double down: Increase the bet 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", and is not always permitted.
signal: place additional chips next to (not on top of) original bet, make "one finger" sign
- Split: Double the bet and have each card be the first card in a new hand. This option is available only when both cards have the same rank or, depending on the locality, value.
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. This option is not always available.
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 player's 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.
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.
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.
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.
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 may give the sharp-eyed player a considerable advantage.