Basic Blackjack Strategy

Contrary to what many gamblers may think, blackjack is not just a guessing game. Most casino games are guessing games. But with any blackjack hand there is a correct strategy and an incorrect strategy. Basic strategy is the correct strategy. The correct strategy is the mathematically optimal strategy—that is, it will maximize your wins and minimize your losses on each hand over time.

You may have noticed that many other popular card games have no basic strategy. There is, for example, no basic strategy for poker. A poker player plays his hands according to whether or not he thinks his opponent is actually holding a strong hand or may be bluffing, and whether he himself is holding a strong hand or may want to attempt a bluff.

A basic strategy cannot exist for any card game as long as your opponent can make decisions, whether those decisions are good or bad, on how to play his hand. For hundreds of years, there was no basic strategy for blackjack because it was not a casino game where the dealer had to show one card and play his hand according to house rules. Instead, it was more of a poker-style game where both of the dealer’s cards were hidden, the dealer could play his hand however he wanted, and players could attempt to bluff the dealer with their own play.

When the American casinos changed the rules of twenty-one to expose one of the dealer’s cards and require the dealer to adhere to a strict hit/stand strategy, an important thing happened. They fundamentally changed the game from a poker-style game based more on psychology, to a purely mathematical game—as far as the player’s strategy was concerned.

Why Basic Strategy Works ... The "Odds"

For our purposes, we’re going to start with an assumption that today’s dealers are dealing an honest game. No sleight-of-hand, no chicanery. We’re not going to forget the First Rule of Professional Gamblers, but we’re going to momentarily disregard it so that we can deal with the logic of the game, and reveal the basic strategy that will kill most of the house’s mathematical edge. The fact is that most of the games you find in casinos these days are dealt honestly, and if you bump into a game that’s not on the level, you’re not even going to try to beat it.

For the honestly dealt game, mathematicians—using high speed computers—have analyzed every possible hand you might hold versus every possible dealer upcard to devise the correct basic strategy for the game. One thing that likely shocked some of the first mathematicians to do these computer analyses was that a nearly perfect basic strategy had actually already been figured out and published by four GIs who had desk jobs and a lot of time on their hands in the mid-1950s. They had no computers, but they’d spent three years using old-fashioned mechanical adding machines to run through all of the possible outcomes of the hands dealt. This may have been the best value Uncle Sam ever obtained from four GIs’ salaries!

We also know that some pretty good approximations of correct basic strategy had been figured out by various professional gamblers in Nevada years before computers came on the scene. These guys figured out the strategy by dealing hands to themselves on their kitchen tables. Thousands, tens of thousands, even hundreds of thousands of hands were required for some decisions. These guys, like most professional gamblers ever since, never published their strategies because they were pros. Blackjack was their livelihood, and they’d spent hundreds of hours figuring it out. Why would they tell anyone else what they knew?

One thing that is certain is that the casinos did not know the proper strategy for the game, and neither did the players who had read the most highly regarded books on the subject. Many of the old Hoyle’s guides advised players to always stand on totals of 15 or 16, no matter what the dealer’s upcard, to split tens and never split nines, and to stand on soft 17. The "smart" players of the time, meaning those who had read one of these books on gambling by one of these reputable authorities, typically made all kinds of plays that we know today to be very costly.

Many people don’t get the logic of basic strategy. Let me give an example. When my hand totals 14, and the dealer shows a 10 upcard, blackjack strategy says to hit. That is the mathematically correct play. Sometimes you will hit that 14 and draw an 8, 9, or 10 and bust. Then the dealer will turn over his hole card, a 6, and you will realize that if you would have stood on your 14, the dealer would have had to hit his total of 16, and he would have busted with that 10. So, by making the "mathematically correct" play, you lost a hand you would have won if you had violated basic strategy.

Some players will argue that there really isn’t a basic strategy that is always correct. Blackjack, they insist, is a guessing game.

To understand basic strategy, you have to start thinking like a professional gambler, and that means you have to understand the concept of "the blackjack odds."

Let me explain the logic of basic strategy using a different example that illustrates how the mathematics of probability and statistics works. Let’s say I have a jar with one hundred marbles in it. Fifty of the marbles are white and fifty are black. You must reach in blindfolded and pull out one marble, but before you do so, you must place a $ 1 bet on whether that marble you pull out will be white or black. If you pull out the color you guessed, you win $ 1; if not, you lose $ 1.

Is this a guessing game?

Absolutely. How could you possibly know which color marble you’re going to pull out in advance? If you win, it’s just good luck, and if you lose, it’s bad luck.

But what if you know that ninety of those marbles are black, and only ten marbles are white? Now, would you bet on black or white before you draw? Any intelligent person would bet on black. It is possible, of course, to pull out a white marble, but you’re much less likely to pull out a white marble than a black one. This may be a guessing game, and you could still lose $1 if you do happen to pull out a white marble, but if you bet on black, the odds are in your favor.

A professional gambler makes his living by always thinking in terms of "the odds", and only betting when the odds are in his favor. With this bet, the gambler would bet on black because the odds are 9 to 1 in his favor. If you bet on white, the odds are 9 to 1 against you.

So, getting back to that total of 14 you had when the dealer showed a 10 upcard, you may lose if you take a hit, but the odds are against you if you stand.

If you make your decisions by playing your hunches, you may win some hands, but you will lose more hands in the long run. There is only one correct decision for any given play, and that decision is based strictly on the math. Whether or not you should hit or stand, or double down or split a pair, depends on what the laws of probability show your expectation to be for each of these possibilities. Depending on the rules and the number of decks in use, basic strategy will usually cut the house edge to no more than about 0.5 percent over you. This makes blackjack the least disadvantageous game in the casino, even if you are not a card counter. It also worth mentioning that in online blackjack the card counting argument completely fails, since decks are shuffled after each hand, and the correct basic strategy becomes even more important.