How Blackjack Works

Dealer Playing Blackjack at a Casino Table
Blackjack also known as 21 is one of the most popular casino games. John Howard / Getty Images

The game of blackjack exists in a gray area in between games of skill and games of chance. Is it a gambling game, like a spin of the wheel or the roll of the dice? Or is it a game that can be learned, mastered, and won by using special systems and methods?

In this article, we'll learn the rules of blackjack, as well as table etiquette for playing at a casino. We'll also talk about odds, counting cards, and why casinos might kick you out if they catch you counting.


Blackjack History

Patrons play blackjack during the grand opening of the Red Rock Casino.
Ethan Miller/Getty Images

Like most games, blackjack wasn't invented at any one time by any one person. Similar games were played in France in the 1700s. One version was knows as Vingt-et-un, which is French for "21." The game traveled to North America with French colonists and spread throughout the continent. It evolved over time, and continues to evolve today.

The game was still called "21" when Nevada first made gambling legal in 1931. To attract more attention to the game, some casinos offered a special bet: A hand that featured the Ace of Spades plus either of the black jacks in the deck (the Jack of Clubs or the Jack of Spades) would pay 10-to-1 odds on the player's bet. Although casinos have long since stopped offering these extra payouts, the name "blackjack" stuck, and today it is one of the most popular table games at casinos around the world.


In the next section, we'll learn the basics of blackjack.

Blackjack Basics

The rules of blackjack are quite simple, which is a major reason for the game's enduring popularity. The object is to get a hand with a value as close to 21 as possible without going over. A hand that goes over 21 is a bust. The players at a blackjack table do not play against each other; they play against the dealer. Each player only has to beat the dealer's hand.

In blackjack, the suits have no meaning. Number cards have a value equal to their number, while all the picture cards (Jacks, Queens, and Kings) are worth 10. Aces can be worth 11 or one, whichever is more beneficial to the person holding the hand. For example, a hand with an Ace and an Eight is worth 19 (the Ace is valued at 11, known as a soft Ace). A hand with an Ace, a Four, and a Nine is worth 14 (the Ace is valued at one, known as a hard Ace, because if it were valued at 11 the hand would bust).


A blackjack table is a semi-circle. The dealer stands at the center of the straight side, and the players sit around the arc of the circle.

Casino tables have betting limits, usually posted as a minimum and maximum bet. To join a game, a player simply sits down at an open seat and places a bet in the small marked area on the table directly in front of him or her.

Now let's see what happens after the bets are placed on the table and the dealing begins.

Blackjack Play

After all bets have been placed, the dealer deals two cards to each player, moving around the table and dealing one card at a time. In a Nevada Deal game, the players' cards are dealt face down. The dealer then deals himself two cards -- one face up and one face down. In a London Deal game, the players' cards are dealt face up, and the dealer deals himself one card face up. In each case, the players are able to see one of the dealer's cards.

Each player in turn decides if his hand is close enough to 21 that it can beat the dealer's hand, based on the one dealer card he can see. If so, he stands, and the play moves to the next player. If the player wants to try to get closer to 21, he requests a hit, and the dealer deals him an additional card. If the player hasn't busted from the first hit, he gets to decide if he wants to be hit again or if he wants to stand. Play never moves to the next player until the current player either busts or stands.


Once all the players at the table have made their plays, the dealer reveals his second card (in Nevada Deal) or deals himself a second card (in London Deal) face up. If the dealer's total is 17 or higher, he has to stay. If his total is 16 or less, he has to hit. The dealer never gets to choose -- he must play by these rules for every hand. If the dealer busts, everyone at the table who didn't bust wins.

If the dealer doesn't bust, the dealer's hand is compared to each player's hand. The higher total wins, netting a 1-to-1 payoff for the player. A tie is a push -- the player gets his bet back, but wins nothing.

Getting a blackjack (an Ace and a card worth 10 as your opening two cards) is like an instant win. It pays at 3 to 2, or one and a half times the original bet. The dealer can also get a blackjack, in which case everyone at the table loses. If both the dealer and a player get blackjack, it's a push.

Blackjack Options

There are a few extra options for the players at a blackjack table:

  • Doubling Down - After the initial deal, the player can double the amount of his original bet; but he must take an additional card (and only one card) from the dealer. If he wins, he wins a 2-to-1 payoff on the total amount of the doubled bet.
  • Splitting - If the player is dealt a pair in his opening two cards, he can split them into two separate hands. Any two cards that are each worth 10 (Tens, Jacks, Queens, or Kings) are considered a pair for the purpose of splitting. Both hands are played independently of each other, and a new bet equal to the original bet must be placed on the new hand. If another pair is dealt onto one of the two hands, it may be split again, resulting in three hands. Some casinos limit the number of splits a player can make on one play. A split hand cannot become a blackjack, even if an Ace and a 10-value card make up the hand -- it still counts as 21, but not as a natural blackjack.
  • Doubling after Splitting - Some casinos allow a player to double down on one or more split hands.
  • Surrender - Once the dealer has checked and found that he does not have blackjack, players can surrender their hand and get half of their bet back. This option is offered most frequently in casinos outside the United States. The option to surrender before the dealer has checked for blackjack is known as Early Surrender.
  • Insurance - Whenever the dealer has an Ace showing, he offers the players the chance to buy insurance. Buying insurance is like betting that the dealer will have blackjack. If the dealer does have blackjack, the player is paid at 2-to-1 on the insurance bet, which can be up to half the amount of the player's original bet. Many inexperienced blackjack players think buying insurance is a great idea, but most experts agree that it is a bad bet.
  • Five-card Charlie - Some casinos reward a hand called Five-card Charlie. If you keep hitting until you have five cards, and on the fifth card you still haven't busted, you win. Five-card Charlie pays 2 to 1, but the rule does not apply after you've split (see above) or if the dealer has a blackjack.

Now we'll take a look at the unwritten rules of blackjack.


Table Etiquette

Although the game itself is simple, there are casino rules and traditions that are important to follow in order to avoid a reprimand from the dealer.

  • Once you've place your bet, don't touch the chips. The dealer might think you're trying to sneak extra chips into your bet because you have a good hand.
  • If you're doubling down, place the additional chips next to the original chips that you bet, not on top of them. The dealer doesn't always count your bet ahead of time, so he might think you're adding more than double to your bet when you mix the two together.
  • In a London Deal game, in which you get your cards face up, do not touch your cards. Casinos prohibit this to prevent players from marking the cards in some way.
  • If you're playing Nevada Deal, you'll have to pick up your cards to look at them. Never touch them with two hands, and don't handle the cards more than necessary. Always keep them above the table, in plain sight.
  • Making your play at a blackjack table is not quite as simple as telling the dealer, "Hit me," or "Stand." In a crowded, noisy casino, it would be very easy for the dealer to misunderstand what you say, or hear the play at another table and think it was yours. That's why hand signals are required.
  • The dealer's eyes will be on the cards almost all the time. When you want another card, say, "Hit me," and make a brushing or scratching motion behind your cards. (If you're holding your cards, you can brush them against the table behind your bet.) Imagine that you're making a slight, subtle, upside-down "Come here" motion, and you'll get the idea.
  • The signal for standing is a small wave of the hand while saying, "Stay," or "Stand." Imagine that someone has just offered you a large slice of pie, but you just ate and you're stuffed. That "No, thanks" hand motion is similar to the signal for stand. (Alternately, slide your cards face down under your bet.)
  • It's vital to pay attention at the table. One story goes: A gambler looked away for a brief moment when a waitress asked if he wanted a drink. He inadvertently left his winnings from the previous hand in the betting circle (a substantial amount), and turned around to find the dealer had dealt him in with a $500 bet. Before he had a chance to complain, he glanced down to find he had been dealt a natural blackjack. That was a surprise happy ending, but his inattention at a key moment could easily had led to a huge loss.
  • Tipping the dealer, known as toking, is customary but not required. The usual practice is to place the chips you're tipping with on the edge of the betting area between you and the dealer. You're actually betting the tip for the dealer. If you win the hand, the dealer gets twice the tip. If you lose, the dealer gets nothing.
  • It's a good idea to exchange your cash for chips at the casino's cage before you start playing. However, there is usually a cash box at the blackjack table. You can place the money you want to play with on the table, and the dealer will exchange it for chips. In some casinos, you might even be allowed to bet with cash, but your winnings will be returned as chips. The dealer can't and won't change your chips back into cash -- it's back to the casino cage for that. The dealer will, however, allow you to trade in stacks of small-denomination ships for larger-denomination ships.

Now you know how to play blackjack. Next, we'll learn how to win.


Basic Strategy

Playing a basic strategy in blackjack requires no card counting, although it does require some memorization. A basic strategy involves:

  • looking at the cards you hold
  • looking at the dealer's face-up card
  • determining the odds that either you or the dealer will bust

Before we get into the details of a basic strategy, it's important that we know the odds. Blackjack, like all casino games, is set up so that the house has an advantage. If you were to play exactly like the dealer (stand on 17 or higher, hit on 16 or less), it stands to reason that there would be no house advantage. Both you and the dealer would win an equal number of times. However, the dealer plays after the players, which means that when you and the dealer both bust, you still lose. Taking into account the payout bonus for getting a blackjack, it works out to roughly a 5.5 percent house advantage. That means that if you were to play blackjack for a very long time (eight hours a day for several years), you would end up losing about 5.5 percent of your money.


So how does a basic strategy work? Entire books have been devoted to the subject, but all basic strategies revolve around the fact that there are more cards worth 10 in the deck than any other value -- 16 out of 52 cards are worth 10.

Knowing this, a basic-strategy player assumes that the dealer's second card will be worth 10, even though many times it isn't. Based on the dealer's "up card" (the card the players know the value of), the dealer's hand can be placed into two categories:

  • hands that are likely to bust the dealer
  • hands that are likely to give the dealer a good hand

If the dealer is showing a Two, Three, Four, Five, or Six, he is more likely to bust. The Five and the Six are the cards most likely to lead to a busted hand for the dealer. In this case, the player doesn't have to take big risks to try to get closer to 21 -- he simply needs to avoid busting himself.

If the dealer is showing a Seven or anything higher, there is a significant chance he will make a good hand of 18, 19, 20, or 21. If the player has a hand with a lower value than 18, he might want to be more aggressive and take another card, risking a bust to try to get a better hand.

So, getting more specific, here are four easy rules on when to hit and when to stand:

  • If your hand is 11 or less, always hit. You can't possibly bust, so the extra card will only help your hand.
  • If your hand is 17 or greater, and the dealer is not showing a Seven or higher, always stand. The risk of busting if you hit is very high.
  • If your hand is 12 to 16, and the dealer is showing an up card likely to bust (see illustration above), always stand. Although this is a weak hand, it will still win if the dealer busts.   Exception - If the dealer has a Two or a Three showing, hit if you have 12.
  • If your hand is 12 to 16, and the dealer has a Seven or higher showing, always hit. The dealer is far more likely to get a better hand than yours unless you can improve it. There's a risk of busting, but in this case you have to take that risk.

Exception: If you're holding a soft Ace, you can be more aggressive than these rules indicate. You might even hit on a 17, depending on what the dealer is holding.

Although basic blackjack strategies can get infinitely more complex, those four rules are the core of most of the strategies in use today.

If you're wondering what card counting is, and if you're even allowed to do it, we'll explain it all in the next section.

Card Counting

Card counting is really just an extension of the basic strategy. It doesn't require a photographic memory or a degree in mathematics. Although the first card-counting systems were developed and published in statistical journals by mathematicians, the actual counting isn't that hard. The hard part is keeping from getting thrown out of the casino.

Counting cards is not cheating. The casinos tried to get laws passed that would make counting a crime, but the courts declared that counting is simply a skillful use of the information available to the player. Which means it's okay to count, right?


Not so fast. Casinos are private property. They can throw you off their property for any reason at all, including playing a game so well that they start to lose money. And once you've been kicked out, returning can result in a trespassing charge. We'll explain how to avoid getting caught in a minute, but first you need to learn how to count.

The basic strategy is based on odds that take into account all the cards in the deck. There's a slight flaw with that strategy, however: After a hand is played, the dealer puts the used cards in the discard tray, and deals the next hand with the remainder of that same deck. Approximately half to three-quarters of a deck might be used before the dealer reshuffles. That means that there are a lot of cards in the discard tray that a basic strategy is still accounting for. Card counting systems calculate the odds of a 10-value card being drawn based only on the cards still in the deck.

One common card-counting system assigns a value to certain cards in the deck:

  • Twos through Sixes are given a +1 value.
  • Tens through Aces are given a -1 value
  • Sevens, Eights, and Nines are valued at zero.

As the player sees the cards being played (and subsequently discarded), he adds those values together. From a starting point of zero, this "running count" fluctuates between negative and positive values. If the first hand dealt from a deck has a Two (+1), a Nine (0), a King (-1), an Ace (-1), a Ten (-1), and a Jack (-1), the running count is -3.

The higher the running count, the more low-value cards have gone into the discard tray. That means there is a higher percentage of high-value cards still in the deck. Why is that important? Recall how the basic strategy is based on the assumption that the next card will be a 10-value card. If you know that there is a greater percentage of 10-value cards in the deck than usual, that assumption -- and therefore the overall basic strategy -- becomes that much stronger.

So how does card counting change the rules of the basic strategy? It doesn't. What it does change is how much you bet.

A typical "system" player (someone who uses a card-counting system) will bet the table minimum when the deck is fresh. When the running count hits a certain level, such as +4 or higher, the player then makes a much larger bet or doubles down aggressively. The higher the count, the bigger the bet. The system player uses these beneficial odds to make a big win or two while the deck is "hot." If the count drops below zero or the deck is shuffled, he returns to the minimum bet.

In the next section, we'll explain how the casinos try to stop the counters and how the counters try to hide their advantage.

Casinos vs. Counters

Casinos have taken a number of steps to negate the advantage gained by counting cards since the first counting systems were introduced in the early 1960s. In many ways, these "countermeasures" have worked, and the card counter of today doesn't have as much of an advantage.

The first attempt to stop counters was a clumsy move in which casinos sharply limited the players' ability to double and split. The result was a drastic decline in players at the blackjack tables, so the rule change was revoked. The casinos' next attempt was the real counter-killer.


Until card counters arrived, blackjack was played at casinos in much the same way you might play it at home -- with a single deck of cards. To make it harder to keep track of the cards in the deck, casinos soon switched to a multideck game, with two decks shuffled together. Today, most casinos use six, eight, or even more decks shuffled together. This is why few dealers deal by hand. It's too hard to handle that huge stack of cards. Instead, they use a plastic box called a shoe.

With so many cards in the deck, each card represents a smaller percentage of the deck, so counting provides a smaller advantage. Methods have been devised to account for multideck play (see sidebar), but the fact remains that it makes things a lot harder for card counters.

The casinos didn't stop there. They also burn (discard) more than one card, or burn cards after every play. Usually, the burn cards go into the discard tray, and the player never sees them. This is obviously a major hindrance for the card counter.

Blackjack dealers also tend to shuffle the deck more often. This resets the count and prevents the counters from getting a favorable deck with a high count. If a player suddenly makes a large bet after betting the minimum for many hands, the dealer may suspect a counter and shuffle immediately.

If someone continues to win at the blackjack table despite all these obstacles, the casino will simply apply "heat." The pit boss or several security guards may arrive at the table and take a sudden interest in the winning player, watching him carefully and closely. As a last resort, they may simply escort the counter out of the casino and ask him not to return. Well-known counters will have their picture posted, so casino security will know them by sight. As Michael Benson put it in his blackjack strategy book, "You can tell that you are getting to be a good blackjack player not just when you go home with more money than you started with, but when casinos begin to keep an eye on you."

The system players aren't left defenseless, however. While casino pit bosses are able to easily spot individual counters by their sometimes slow play and obvious betting patterns, blackjack teams have walked away from the casinos with millions of dollars before the casinos caught on. One legendary team from the Massachusetts Institute of Technology practiced in mock casinos and refined its techniques over the years, winning big before they were discovered. (You can read about the strategy in Bringing Down the House: The Inside Story of Six M.I.T. Who Took Vegas For Millions, by Ben Mezrich.) Here is an example of a typical blackjack team making a run at a casino:

One player, the spotter, sits at the table playing the table minimum. His bet never varies. At the same time, he's counting cards carefully, but not obviously. Because his bet never changes, the pit bosses never suspect him of counting. If the casino is very busy, a back-spotter might be used. Typically, this is a female team member, made to look like a player's girlfriend, standing behind him and rubbing his shoulders as he plays. The whole time, she's keeping up the true count.

Meanwhile, another team member is hanging around nearby, but he's not playing blackjack. Taking advantage of common stereotypes that pit bosses encounter, this player might be a young man who looks like he could be the son of a rich, foreign businessman -- a big spender (known among casino owners as a "whale"). When the true count shows an advantageous deck, the spotter gives a subtle signal to the big spender. A hand in a pocket or arms folded across the spotter's chest are enough to bring the big spender over to the blackjack table. Acting like a drunk, reckless rich kid, the big spender lays down a huge bet as soon as he reaches the table and keeps betting big until the spotter signals that either the count is getting low or the pit boss is getting suspicious. Then the big spender stumbles away with his winnings, and no one on the team ever changed their betting pattern or did anything else the casinos usually look for in catching counters.

Now, counting is hard, but cheating at blackjack is even harder. In fact, it's usually the players getting cheated, not the casinos.


There are few options for the solitary player who wants to cheat at blackjack. Marking cards is one possibility, but with constant video surveillance it's nearly impossible to avoid getting caught. A player switching his cards with hidden cards is another choice, but the dealer will usually call "Card down" the instant a card moves below the table.

Working with the dealer opens up many more possibilities for cheating. The dealer holds the cards most of the time, and is often incredibly adept at sleight of hand. Skilled dealers can stack the deck, deal whichever cards they want, and decide exactly who will win and who will lose at the table. An agreement with a player to split the winnings could be very profitable for both the dealer and the player.


More common, according to blackjack expert Lance Humble, is the dealer who cheats on behalf of the casino. There are a number of reasons for this. If a dealer has had a bad run and lost a lot of house money, he may be tempted to deal in his own favor to put some money back on the casino's side of the ledger.

In the days when organized crime was more openly involved with casino gambling, many gamblers told stories of players who walked up to a table and instantly started winning on huge bets. Meanwhile, the dealer and pit boss would look on as if nothing was wrong. Humble's suspicion is that these players were criminals known by the dealers, and the dealers were also being paid off by crime lords. The dealer would make sure to deal himself poor hands while the connected player was at the table.

Humble even tells one story in The World's Greatest Blackjack Book of a dealer who manipulated the play just because one of the players annoyed him. The obnoxious player got on everyone's nerves, and after several hands, the dealer started announcing, "good," or "bad," as he dealt each player their cards. The annoying player was always told "bad." For more than a dozen hands, he lost every play, while the "good" players raked in their winnings.

With casinos springing up in every state, blackjack is more popular than ever. While there are professional blackjack players, and there is even a World Series of Blackjack, for the overwhelming majority of players the game is a much better way to lose large amounts of money than to make any.

For more information on blackjack and related topics, check out the links on the next page.

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