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The 10 Commandments of Blackjack Gambling

| August 27, 2015 12:00 am PDT
Man At Blackjack Table|Man At Blackjack Table

I’ll be the first person to admit that I’m not the best blackjack player in the world. But I have been reading about, writing about, and playing blackjack for the last 20 years. In that time, I’ve picked up some essential tips about gambling on 21.

I share them here as “commandments” with my tongue planted firmly in my cheek. You can, of course, play the game any way you like. But if you’d rather play smart, obey these tips to the letter.

1. Thou shalt not play 6:5 Blackjack.

One of the best rules in blackjack is the 3 to 2 payout when you get an ace and a ten on your initial hand. This is called a “natural” or a “blackjack”. But you’ll find more casinos than ever offering games where the payout for this hand is only 6 to 5.

Here’s how that works:

In a normal blackjack game, you bet $100. You get a natural. Your payout is $150.

In a 6/5 blackjack, you bet $100. You get a natural. Your payout is only $120.

Casinos offer other rule changes that favor the player in exchange for the reduced payout, but these rules are never good enough to account for that lower payoff on a natural.

Here are some examples of those favorable rules:

  • Single deck game
  • Dealer stands on soft 17
  • Player can double after splitting
  • Player can double on any 2 cards

These rule changes do have an effect on the house edge. A single deck game has a house edge 0.61% better than a single deck game. The dealer standing on soft 17 instead of hitting has a house edge of 0.2% better. Being able to double after splitting is good for almost 0.15%. Being able to double on any two cards is worth about 0.2%, too.

In fact, if you combine all the rules variations I listed, you’ll get a net gain of 1.2%, which is significant.

Here’s the problem, though:

6/5 blackjack gives the house an extra 1.35% edge.

And most casinos don’t give you ALL the good rules. They just give you enough good rules to convince you to try their 6/5 game.

Don’t do it. Even if you’re an excellent card counter, overcoming that extra 1.35% is tough.

Want to know how much that would actually cost you?

Assume an average 3/2 blackjack game offers the house an edge 1%. The 6/5 version has a house edge of 2.35%, instead.

Assume 60 hands per hour at $10 per hand. That’s $600 in action per hour.

You’ll lose, on average, $6 per hour playing the standard game.

But if you play 6/5 instead, you’ll lose an average of $14.10 per hour.

Just say no to 6/5 blackjack. If enough players refuse to play, the casinos might stop offering it.

2. Thou shalt not deviate from basic strategy.

On any given hand, you’ll have the following possible choices:

  1. Surrender
  2. Double
  3. Hit
  4. Stand
  5. Split

Some of these options are only available on certain hands. For example, you can only split if you’re dealt two cards of the same rank. In some casinos, you’re only allowed to double down on certain totals.

You’ll notice that I didn’t include “insurance” as one of the options—that’s not a mistake. Insurance is an optional side bet that you should never take unless you’re counting cards. It’s not a choice about how to play your hand.

Based on the cards in your hand and the dealer’s up card, only one of those five choices is the best choice—the option that offers you the highest possible expected value.

Basic strategy outlines the mathematically best way to play every hand in every possible situation. You can learn basic strategy elsewhere on this site, or you can just buy a strategy card in the gift shop of the casino.

Either way, you should NEVER deviate from basic strategy. Some of the choices might seem wrong to you somehow. That doesn’t matter. Make the mathematically correct decision anyway.

You might have a hunch about how the hand is going to play out. Ignore your hunches, and follow basic strategy instead.

The difference between using basic strategy and just guessing at how to play each hand is huge.

Want to know how huge?

Assume you’re playing perfect basic strategy in an average game. The house has a 1% edge. You’re playing 60 hands per hour at $10 per hand. Your mathematically expected loss per hour is $6.

If you’re just playing your hunches, the house edge is between 3% and 4%. We’ll assume that your hunches are especially lucky, and the house edge is only 3%. Your mathematically expected loss per hour is $18.

Blackjack is entertainment, just like going to a movie. Suppose you went to a movie theater, and the counter person told you that you could buy a ticket to a movie for $6 or $18, your choice. No difference between the movie, your seat, or anything else.

You wouldn’t choose the $18 ticket, would you?

Ignoring basic strategy is the same as buying the $18 ticket.

3. Thou shalt not take insurance.

A common beginner mistake is to take insurance. But insurance is actually one of the worst bets you can take.

Here’s how insurance works:

The dealer has an ace as her up card. She asks you if you want to take insurance.

If you say yes, you put up a second bet equal to half of your original bet. If the dealer has a 10 in the hole (a blackjack), you win 2 to 1 on the insurance bet. You still lose your original wager.

If you’re playing for $10 per hand, insurance is a $5 bet that pays off $10. But you lose your original $10 wager if the dealer has a blackjack, which is basically a tie—a win of $10 combined with a loss of $10 is a net gain of 0.

On the other hand, if the dealer doesn’t have a blackjack, you lose the $5. You might win or lose the hand, but that $5 is gone.

The question you should ask yourself is this:

What are the odds that a dealer actually has a 10 in the hole?

The answer is actually simple. A deck of cards has 13 ranks:

  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10, J, Q, K
  • Ace

The 10, J, Q, and K are all listed on the same line because they all have the same value—you have 4 possible 10s. You have 9 other possibilities.

Your odds of the dealer’s hole card being a 10 are 9 to 4. You have 9 ways to get a result of anything BUT a 10, and only 4 ways to get a result of 10.

Those aren’t good odds. Basically, your chances of winning that insurance bet are only about 30.7%. You shouldn’t take bets that pay off 2 to 1 if your chances of winning are only 30.7%.

Here’s why:

You take insurance 100 times for $5 each time. You win about 30.7% of those bets, but you lose about 69.3% of those bets.

When you win, you get $10. In those 100 hands, you’ve won about $300.70 (30.7 X $10).

When you lose, you lose $5. In those 100 hands, you’ve lost $346.50 (69.3 X $5).

Your net loss is almost $50 for every one hundred insurance bets.

The ONLY time you should take insurance is when you’re counting cards. Depending on the system you’re using, you can get an edge taking insurance when the “insurance index” is at a certain level. For example, if you’re using the Hi-Lo Card Counting system, the insurance index is 3—you would take insurance if the true count is 3 or higher. Otherwise, you’ll turn insurance down, too.

NEVER take insurance unless you’re counting cards.

4. Thou shalt not split 4s, 5s, or 10s.

Of course, if you’re following the commandment about playing according to basic strategy, you’ll never make the mistake of splitting 4s, 5s, or 10s, but even so—some players get confused on these hands.

Why wouldn’t you want to split 10s?

You’d get 2 chances to get a blackjack. That sounds like a good deal to a lot of players.

The problem is that 12 times out of 13, you’ll miss that ace. You might still have a good hand, but a total of 20 is way better than two hands with a 1 in 12 chance of getting a blackjack.

Why wouldn’t you want to split 5s?

In this case, you’re trading the opportunity to double down on a total of 10 for 2 inferior hands. In fact, a 5 is one of the worst hands you can start with. No additional card is going to turn a 5 into a good hand. It takes multiple good cards to do that.

If you have a 5 and you get dealt a 10, then you have a total of 15. That’s nothing to get excited about. If you’re dealt an 8 or 9, you have a total of 13 or 14. I don’t know anyone who’s going to get excited about either of those totals.

In fact, the best you can hope for with a 5 as your first card is to be dealt a 6, giving you a total of 11. Even then, you have another card to come, and most of the time it won’t be an ace.

Why wouldn’t you want to split 4s?

A pair of 4s is similar to a pair of 5s, except you don’t get to double down most of the time. With a pair of 5s, you can double down and hope for an ace or a 10. But with a pair of 4s, if you double down and get a 10, you have a respectable total of 18.

But if 4 is a starting card, you’re in the same boat as if you had a 5. The best you can hope for is a 7, which gives you 11, but you still have to hope for that 10 on the next card.

So follow basic strategy. But even if you don’t follow basic strategy, never split 4s, 5s, or 10s. In fact, memorizing that covers a tiny percentage of basic strategy decisions already.

5. Thou shalt always split aces and 8s.

Basic strategy says you should do this. Here’s why:

If you have a pair of aces, you’re looking at a soft total 12. That’s not a hand to be excited about. It’s not terrible, but it’s not exciting.

On the other hand, if you split those aces, you get 2 chances at hitting a blackjack. You’ll miss most of the time, but you’ll hit your natural a little less than a third of the time.

If you have a pair of 8s, you’re looking at a hard total of 16. That’s not such a great hand. Against half of the dealer’s up cards, you’ll want to stand—but you’ll often lose to a higher total from the dealer. The other half the time, you’ll have to hit, but in those cases, you’ll bust a lot of the time.

On the other hand, an 8 isn’t a bad first card. You’ll get a total of 18 if one of the four 10s in the deck comes up next. If you get a 9, then you’ve got a respectable total of hard 17.

But the main reason you always split 8s—indeed, the main reason you always split aces and never split 4s,5s, and 10s—is because it’s the highest expected value play in that situation.

Pay attention to commandments 4 and 5, and you’ll have much of the basic strategy for splitting pairs memorized.

You’re well on your way, now.

6. Thou shalt not imitate the dealer’s strategy.

Common sense might seem to indicate that if the house has an edge using their strategy, maybe you could get an edge—or at least eliminate the house’s edge—by using an identical strategy.

What common sense forgets is that the house isn’t playing by the same rules.

Here’s why:

The dealer checks for a total of 21 before allowing the players a chance to play their hands. If she has a 21, she wins, and you don’t even get to try to get a push.

If she doesn’t have a 21, all the players have to play their hands before the dealer plays hers. If a player busts, the dealer wins instantly. Even if the dealer busts later, she won those bets from the players who acted before she did.

That’s a huge advantage, and it’s the main reason that imitating the dealer’s strategy makes no sense. Stick with basic strategy, please.

7. Thou shalt not criticize other players’ decisions.

The players who criticize the other players’ decisions are irritated because they’re proceeding from a faulty assumption. They think that a player who acts before them and makes a mistake has hurt their chances of winning. In reality, this isn’t the case.

The math changes a little bit every time a card is dealt, true. But that doesn’t always mean that a player’s mistake hurts you. Depending on the cards, it might help you just as often.

Blackjack critics never chastise other players when this happens, though.

8. Thou shalt not reinvent the wheel.

Basic strategy has already been invented. It’s a wheel.

Card counting has already been invented. It’s another wheel.

Trying to come up with a new system of getting the best odds against the dealer in blackjack is a futile endeavor. We already know how to minimize the house’s odds. We even already know how to get an edge against the casino.

Instead of trying to come up with some new way to minimize the house edge or get an edge over the casino, just learn the basics.

Basic strategy works.

Card counting works.

You don’t have to reinvent the wheel to win more at blackjack.

9.  Thou shalt not stand on soft 13 through 17.

Soft hands throw a lot of players off. They don’t have to, though. Just memorize basic strategy, and don’t deviate from it.

In some cases, the correct strategy for a soft 13, 14, 15, 16, or 17 will be to hit. In other cases, doubling down is the correct strategy.

Standing on these totals is never the correct strategy.

10. Thou shalt not kill the golden goose.

If you find a way to get an edge over the casino, don’t do stupid stuff to eliminate that edge. For most people, this means using some restraint when counting cards.

Here’s an example of killing the golden goose:

You find a casino offering a good game. You estimate that you have an edge of 2% over the casino in this situation. You play blackjack for 8 hours and make a nice profit.

You come in during the same shift the next day, and play for 8 more hours.

You keep playing until they notice you’re always winning, and they ban you from the casino.

Good-bye, golden goose.

In reality, you won’t get away with counting cards at the same table for more than 45 minutes. You shouldn’t even try. Stick with short 30-45 minute sessions when you find a positive situation.

When your session is up, move on to another profitable session at another casino.

Don’t hit the same casino during the same shift every day, either. Mix it up.

Your goal as a card counter is to remain as forgettable and anonymous as possible. The last thing you want is to be recognized by the staff as a “regular”.

You might have seen the movie 21. If so, you probably think you should act like a drunk or a rich gambler from a foreign country in order to get away with placing a really big bet and making a big score when the count is in your favor.

That’s not how it’s really done—not for most people, anyway.

If you do get some heat from the casino, don’t argue. Collect your chips and leave. You don’t even want to stick around long enough to cash in your chips.

You can come back in and cash your chips during a different shift later that week.

Then stay out of the casino for 6 months. When you return, don’t play during the shift when you got heat. After a year, you might be able to hit that shift again, but don’t try any sooner than that.

A lot of card counters who lack patience get banned for life.

That’s so unnecessary.

Just exercise some restraint.


Blackjack isn’t the most complicated game in the world. But it’s easy to make mistakes that can cost you a lot of money over time. And if you aspire to be more than a recreational player, you have to get your percentage of mistakes to near zero to succeed.

Most of the “commandments” on this page are intended to increase your enjoyment of the game, not decrease it. I’ve never met a blackjack gambler who didn’t prefer winning over losing. These tips will increase your odds for the former and decrease your odds for the latter.



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