Elements of Basic Strategy

Definitions

A distinction is drawn between hands in which an ace counts for 11 and hands in which there is no ace or the ace counts for 1. The former are called “soft” hands. They range from soft 13 (ace and deuce) to soft 21 (ace and ten, a natural). By contrast, “hard” hands range from hard 12 to hard 21. Below 12, hands are neither hard nor soft, as they will not have an ace (or else they would become a soft hand from 13 to 21). Often these are called “low” hands. Pairs are treated as special cases, so that is why the lowest soft hand is 13 (because a 12 would be a pair of aces, to which different rules apply). This also explains why the lowest of the low hands is a 5 (since 4 or less either involves an ace or a pair). This terminology may seem a little tricky at first, but it will make sense very quickly once you try your hand at applying the principles.

Another set of terms is important for understanding the strategy. There are low cards and high cards. Low cards are two through six. High cards are seven through ace. (This usage is different from the HiLo usage in card counting, in which cards are divided into three groups of high, low and middle.) For purposes of basic strategy, there is a cutoff at 7. It has to do with the fact that 38½% of the cards in the deck are worth ten or eleven points, and any card greater than 7, when combined with a ten or ace, will bring the dealer to a pat hand. Basic strategy is frequently sensitive to whether the dealer shows the threat of a pat hand by displaying a seven or higher.

Not to be confused with a “low card” is a “low hand.” It is a hand adding up to eleven or less. The relevant point is that taking a hit is safe, since busting is not possible.

Splitting and Double Down

Many players imagine that you should split all pairs, and have no idea when to double down. If these two devices were not present, Basic Strategy would be much simpler – just a case of knowing when to hit and when to stand. The dollar benefit of splitting and doubling is the difference between a noticeably negative-expectation game and one that is just about even or maybe a little positive. Splitting or doubling at the wrong time, or worse, failing to split or double at the correct time, are mistakes that will cost the player the extra bit of earnings that keep him or her on even terms with the casino. Double Down is called for when the odds of a victory are significantly higher than usual. The player gives up the chance for multiple hits, which is a concession of some value, in exchange for being able to exploit a game situation in which the cards disfavor the house. Usually this occurs when the dealer’s up card is in the 3-6 range (making a bust more likely) or the player’s hand is in the 10-11 range (making a high pat hand more likely). Splits follow the same kind of thinking. Splitting also doubles the bet by doubling the number of hands being played. Unless splitting improves the chances of winning a hand (or two), it makes no more sense to do it than it does to double down in a bad situation.

For example, splitting 8’s makes sense, as 16 is a weak hand, but splitting 9’s does not always make sense, as 18 is a fairly good hand. The most complicated part of basic strategy is keeping track of when one should double or split (and conversely, when not to do it). The devil, unfortunately, is in these details.

One point of clarity on double down is necessary. Double down is usually only permitted on two cards, before a third card is drawn. If the total in the player’s hand would suggest double down, but it can not be done because it is a three-card hand (or more), then the player should just hit or stand according to what the underlying principle suggests. This is not hard. Basically, with a soft 18 that can not be doubled, stand instead. In all other situations where doubling is recommended, but not feasible, hit instead..

The Sequence of Questions

Basic strategy follows a certain sequence to evaluate a hand.

First, ask, “Do I have a pair?” If so, then ask if you should split the pair or treat it as a single hand.

Second, it you don’t have a pair or choose not to split the pair, ask “Do I have an ace?” If so, do the rules for soft hands apply? The choices are hit, stand or double down.

Third, if you do not have an ace, or if you have one, but it is valued as a 1, then apply the rules applicable to hard hands or low hands. The choices are hit, stand or double down. In only a couple of circumstances does basic strategy recommend surrender, if it is available.

Tables of basic strategy are usually presented in this decision order, that is, the rules for pairs first, then soft hands, then hard hands, then low hands.

The underlying logic of basic strategy does not necessarily follow this same pair-ace-hard hand sequence. It comes from a couple of realizations that one can see by studying the patterns in the table.

Principles of Basic Strategy

Some hands are easy to play, as the rule will be the same, regardless of the dealer’s up card. Others require checking what the dealer is showing. The following principles cover what to do on each occasion.

4.1. Stand with a “pat” hand. This is a hand that’s worth 17 or more.

Exceptions: The exceptions depend on the dealer’s up card. They are:

(1) a pair of 9’s. Nines should be split unless the dealer’s up card is a 7, ten or ace. The 7 might lead to a 17, which the 9’s can beat without splitting. The ten or ace is likely to lead to a 20 or 21, which the split 9’s can not beat, potentially costing the player two bets.

(2) “soft” 17 and “soft” 18 should be doubled (if possible) if the dealer’s up card is a 3, 4, 5 or 6. Otherwise, soft 17 should be hit and soft 18 should stand. However, if the dealer shows a 9, 10 or ace, soft 18 should be hit, just like soft 17. (Do not fret -- this is basic strategy’s most Byzantine rule.) The low up cards mean that the dealer can not reach 17 without taking another card, thus opening the door for a dealer bust. That explains the double down recommendation. Otherwise, if the dealer shows a 7 or better, Soft 17 is a low pat hand with no risk of busting and a good chance for improvement, so hitting it makes sense. On the other hand, soft 18 is a reasonably strong pat hand, so it would be best to leave well enough alone, unless the dealer shows a shot at a 19 or higher. In such a case, it makes sense to hit soft 18.

In summary, stand on 17 or better, except remember that soft 17, soft 18 and double 9’s are special cases.
4.2. Stand with a “stiff” hand if the dealer shows a low up card. The strategy here is that the dealer might bust. A stiff hand is any hard hand (over 11) that is not “pat,” (under 17). For example, a 10-5 combination for 15 is a stiff hand. This rule applies when the dealer’s up card is less than 7, that is, 2 through 6. To make it to 17, the dealer will have to draw at least one card (unless the up card is a six and the hole card is an ace). The “hit” to the dealer opens the way for a dealer bust. For example, with a 5 showing, the dealer will need two cards and a minimum of 12 points. If the two cards yield more than 16 points, that is a victory for the player. The odds are better than even (60% or so) that one of those cards will be a ten. Any other card over 7 would then bust the dealer. Monte Carlo computer simulations indicate that standing on a stiff hand is always a better bet than hitting when the dealer shows less than a 7 as the up card.

Exception: If the stiff hand is a 12 and the dealer shows a 2 or a 3, it is better to hit than stand. Even though this is risky, any card other than a 10 or a 9 will improve the player’s hand; moreover, the odds that the dealer will bust are reduced because a 2 or 3 is so low.

Hit a stiff hand if the dealer shows a high up card (7 or above including ace). Even though there is a palpable risk of busting, the higher card in the dealer’s hand has an equally palpable risk of creating a 17 or higher, and the dealer will thus have already won the hand without having to draw a card. There is a chance, of course that the dealer might not already have a pat hand. Millions of simulated blackjack hands show, however, that the downside of taking a hit is less “down” than standing and having the dealer win without having to hit the hand.

Exception: If “surrender” is an option in the casino you are in, do so if you have a 16 against a 9, 10 or ace. Surrender a 15 against a 10. The loss of a half bet is a better expectation than the less than 50% chance you have of winning.

Hit soft 13 through soft 16 (unless a double down is called for). This principle deals with soft hands that are not “pat.” The dealer’s up card is only important for knowing if a double down is called for. As mentioned above, a dealer up card of 3 through 6 requires that the dealer draw at least one card to reach 17. The chance that the dealer will draw more than 21 is reasonably good. Furthermore, doubling is not that a big risk, as a hit on soft 13 through 16 cannot cause a bust, and a middle-size card could create a strong hand. This is what generates the exception:

Exception: Do not simply “hit” but double down on soft 13 through 16 (if possible) when the dealer shows a low card other than a deuce. (The deuce is not included in the exception because the dealer is less likely to bust with the two showing.)

Hit all hands of 11 or less (unless a double down is called for). You can’t possibly bust at 11 or less, and you can’t win without hitting, unless the dealer busts. So the rule to hit a hand of 11 or less is fairly obvious. The exception is somewhat tricky.

Exception: (a) double down all elevens except against an ace. If the one card dealt after doubling is a ten, you have 21. It’s possible to catch a low card, too, but in the long run, more money is made by all elevens except against a dealer’s ace. (b) double down all tens, except against a ten or an ace. The same thinking applies. With a 10 you’ll have 20, which is a good hand – good against anything but 20 or 21, which is why you don’t double if the dealer shows a ten or an ace. (c) double down all 9’s against low cards except the deuce. If the dealer shows a 7 or more, play it straight, but if the dealer shows a low card, double. The nine could become a strong hand, and the low card means the dealer might bust. Don’t double against a deuce because it is too low to be relied on to cause a dealer bust.

These five principles cover all situations except pairs: They address pat hands, stiff hands and low hands. Even though checking for pairs is the first step in the sequence of evaluating a hand, it comes at the end of the discussion from a logical point of view. Pairs are less common than the other hands, and the underlying thinking strongly mirrors the principles just stated.

Another issue with pairs is that casino rules about them can vary. The inquiry is whether a given casino allows pairs to be re-split after splitting once (if another card of the same rank is drawn) and whether the casino allows a double down on the split pair hands. In Las Vegas it is common to find the rule that re-splitting is allowed at least once and often twice (i.e., up to 4 hands at once) and double down is allowed on the split hands. Because this makes splitting more attractive, the principles in basic strategy for splitting pairs recommend splitting more often under these rules than when the casino vetoes re-splitting and/or double down on splits. The following rules reflect the more common Las Vegas rule that re-splitting and double downs on split hands are OK.

The rules for splits can be summarized as follows:

Split all aces and 8’s. Splitting aces gives two chances for a natural. Splitting 8’s takes a weak hand, perhaps the weakest one, and gives two chances for a decent hand. There are no exceptions.

Never split tens or five’s. Two tens is a 20, and principle 3.1 applies: Stand on pat hands, particularly a 20. The “five’s” rule is the opposite of the “eight’s” thinking. Ten is a rather good hand, and, if it is hit, might generate a winner. Splitting the fives gives two chances for relatively weak (almost the weakest) hands. Remember, by not splitting fives, they are a “ten” and hence should be doubled against anything but a ten or an ace (principle 3.5, exception b). There are no exceptions.

Two’s, three’s, sixes and sevens should be split against low cards and sevens. The one exception to this rule is that sixes should not be split against a seven, as twelve is the easiest stiff hand not to go bust on, and 7 gives the dealer a chance for a pat hand. If not splitting, the hit rule (principle 3.5) applies.

Exception: Do not split sixes against a seven.

Split four’s only against a five or six. Otherwise, hit a pair of fours. The thinking is similar to that for fives. Eight (double 4) is a good number, as it could easily go to 18. Splitting fours leads to two hands that could easily both be stiff. Against a five or six this is worth a risk, as the dealer could wind up easily with a fifteen or sixteen and then bust.

Insurance

Dealers offer insurance bets when the dealer’s up card is an ace. A player can make a side wager of one-half a bet, which will pay 2:1 if won. The bet is that there is a ten under the dealer’s ace. If the dealer has a natural, winning the side bet neutralizes the loss on the main bet for the player. If the dealer does not have a natural, a half bet is lost, but the main bet will still be up for grabs. Dealers and pit bosses have different ways of describing the insurance bet to make it sound like a good deal. It is not. The math differs according to the number of decks in play. Let’s assume 52 cards for ease of the concept. If it’s a new shuffle and you are the only player and do not have a natural or a ten in your hand, then there are 16 cards in the deck that can give the dealer a natural. The deck has 49 cards to choose from. The probability that the dealer’s hole card is a ten is less than 33%, which would be the breakeven probability to pay off a 2:1 bet at a zero edge. The negative edge is small in this circumstance, but it never gets any better. If you have one of the tens in your hand, or if there are other players at the table with tens, the edge worsens noticeably.

Another aspect of insurance is that it is a side bet. There is no assurance that the player will win the main bet just because the dealer has no natural, so it needs to be evaluated on its own merits, without any relation to what is actually going on in the game.

For these reasons, basic strategy recommends never making the insurance side bet, or any other side bet for that matter. The consensus of the experts is that those bets are for suckers. (If cards are being counted, it may be possible to know when the composition of the deck favors the dealer, so the insurance bet will have a positive edge.)

No Double Down on Splits

Many different rule variations from those presumed above are possible. The most common Las Vegas variation would be “no double down on splits.” In such a case, the principles above need to be revised slightly. The exception to principle 4.8 would also say, “Do not split two’s and three’s against two’s and three’s.” Principle 4.9 would say, “Never split four’s.”

No Surrender

If surrender is unavailable, just hit 16 against 9, 10 or ace and 15 against a 10. Dealer Hits Soft 17. Changes to basic strategy are small. This rule variation favors the casino. Even though the dealer may bust more often, the house also wins more hands in the 20-21 range from not standing on 17. This is enough to compensate for the extra busting, and more. The most important rule adjustments are to surrender a pair of 8’s against an ace and hard 17 and hard 15 against an ace. Less critical tweaks involve double down: add it to the play for 11 against an ace, soft 19 against a 6, and soft 18 against a deuce.

Limits on Double Down

Some casinos restrict double down to a point total of ten or more, or rules of similar import. The basic strategy does not change; however, be aware that the house edge just swung a couple of percent in the wrong direction.

The following table is a summary of the principles of basic strategy, arrayed in the evaluation sequence. For review, look over each of the 9 elements of the basic strategy and see if you can identify where this is reflected in the table. The actions are indicated by symbols and colors for ease of reference. Double down is shown as an asterisk, meaning that if it is not possible to double down, just perform the action indicated in the entry for that combination of player’s hand and dealer up card.