Double Down on a 6:5 Blackjack? Read This First…


Bad Choice

The plague of 6:5 blackjack has been well documented here. (See 6 to 5 Blackjack? Just say No! and The Casino Floor as a Minefield.)

If you have any other game choices available, you should not be playing a game that pays only 6:5 on blackjack.

Yet some players do play these games. Don’t worry, I’m not going to chastise you if you sometimes play these games. But I do want to make sure that you are not making a bad game even worse…

How to Give Away Money

Several players have told me that when they are playing a 6:5 game and are dealt a blackjack, they choose to double down on the blackjack as an eleven instead. Ack! No. No. No. Let me explain just how bad an idea this is.

Let’s say you are a $10 player, and are dealt a blackjack at a 6:5 game. Assuming that the dealer doesn’t also have a blackjack, you’ll win $12 on the hand. Guaranteed, with no chance of losing money. This hand is worth $12. Period.

If you decide to double down on the blackjack instead, you’re risking another bet with the hope of winning $20 instead of $12. But you’re giving up the guarantee of a win. Let’s see how that works:

A Bird in the Hand

Let’s take the best possible scenario, a single deck game where the dealer stands on all 17s. We are dealt a blackjack against a dealer upcard of 5. If we let the dealer pay the blackjack, we collect our 6:5 guaranteed win of $12. That’s our “bird in the hand”. For doubling to be a better strategy, our yield on the double down needs to average more than $12. And it’s not even close. Let’s look at what happens when we double.

Two in the Bush

Now we are doubling our bet to $20 and drawing one more card. Remember, I chose the best possible hand for this… (Ace,Ten) vs a dealer 5.

This is a very strong double down hand, but even so, it will win only 63% of the time. 7% of the time we will push, and 30% of the time we will lose. (Here’s how to calculate the value if you are interested: (63% – 30%) X $20 = $6.60. Actually, I rounded off the percentages a bit so the exact answer is slightly different…)

The value of this doubled bet of $20 works out to just $6.82. That’s only a little over HALF the value of the 6:5 blackjack.

In this case, A Bird in the Hand is definitely worth more than Two in the Bush. Every time a $10 bettor chooses to double down on his blackjack, he’s giving the casino an extra five bucks and change. Don’t do it!

6:5 Blackjack sucks. Don’t make it even worse. Do Not Double Down on Blackjack!

9 comments on "Double Down on a 6:5 Blackjack? Read This First…"

  • Kairo said:

    Palace Station has many 6-5 tables now and the 3:2 tables are sometimes full. So I played their 6:5 game for the first time with the tie side bet (half of main bet, pays 10:1 on push). Unless my math is horrible, one should actually double on blackjack for some dealer up cards (if not all?). So using your math, with a dealer up card of 5, the $50 pay out on a tie 7% of the time would add $3.50 to the $6.82. If you take the 6:5 blackjack you only get $7 because you lose the tie side bet ($12-$5). Then the question becomes, Bet $15 to win $7 or double down to bet $25 to win $10.32 with a 5 up card? How does it work out for the other up cards? The tie side bet actually lowers the house edge on a regular 3:2 game but obviously you don’t double blackjack on 3:2 even with the side bet. But I’m curious if the tie side bet substantially lowers the house edge on a 6:5 game if you double some blackjacks?

  • Sam Tanner said:

    I’ve been playing blackjack for a while and counting for about 5 years. I recently (about a year ago) decided to up my game a bit and learn how and when to deviate from basic strategy as dictated by the count.

    I believe it’s Stanford Wong’s book that said that although there are about 50 variations from basic strategy the only 3 of any importance and significance in winning are: (1) taking insurance when the count is +3 or more; (2) stay on 16 vs. dealer 10 when the count is 0 or higher and (3) stay on 15 vs. dealer 10 when the count is +4 or higher.

    I’m embarrassed to say that I also just discovered that there are some basic strategy variations depending on whether or not the dealer stays on 17 or hits. A player mentioned that to me and I wasn’t sure if I should believe him or not because I thought that I had researched this before and couldn’t find any difference or even find mention of a difference. I decided to research it again and discovered your website. With the ability to plug in the casino rules (# of decks, hit or stay on soft 17, etc.) on your site I learned that in fact there is a difference.

    Then I dove deeper into your sight and started going through your course. This is where I have been devastated. I discovered that my whole method of money management was wrong.

    I don’t know where I learned it from but I’m quite sure that I didn’t just make it up. I would multiply my bet by the true count. If I’m playing $25 and the count was +4 I’d bet $100.

    Now I see that not only must you increase your bet by .38% of your bankroll but that percentage is based upon your current bankroll (so as you make lose money that bankroll changes and therefore that betting unit changes).

    I’m devastated! I worked my butt off to learn basic strategy. I learned to count and think that I’m quite good at it. I have the patience to grind it out at a table and play for hours and days at a time to enhance my odds. But: (1) I don’t think that I’m smart enough to calculate .38% of my bankroll as I’m playing and (2) I don’t have enough money to play based upon those guidelines.

    I usually take about $1,000 to play. Based upon that bankroll, unless I’m doing something wrong, the count has to get to +8 until I’m directed to even bet what is typically the minimum ($25) where I play (Maryland Live or Tropicana in AC). Even with a $3,000 bankroll the count has to get to +6 before you can even double your bet. To be able to double your bet when the count is +2 your bankroll has to be around $13,000.

    Please guide me:
    1. Am I now calculating the betting increment correctly?
    2. Am I correct in stating that you need a lot more than $1,000 when counting?
    3. Is there not an easier way to calculate the optimum bet?
    4. Is my method of multiplying my bet by the true count way off base (I suspect it is)?
    5. Is it correct that taking insurance at +3 or more, staying on 16 vs. 10 at 0 or more and staying on 15 vs. 10 at +4 or more are the only variations from basic strategy while counting that make any significant difference in your winning?

    • First, relax! It’s not as bad as you think. But there is both good news and bad news.

      I’ll start with this 0.38% thing… It comes from the GameMaster’s Blackjack School lesson 8, located here:

      The GameMaster School is an excellent resource (that’s why I host it here with his permission!), but I do have my quibbles with it.
      And in my opinion, the approach he uses to teach how to size your bets is confusing and intimidating. His “exact” table of how to figure an optimal bet goes into too much detail for someone just learning to count. I understand that he wants to put real numbers to the concepts, but he really should put a warning above that first table that says “Don’t worry about all these crazy exact numbers… We’ll round them off for easier actual bet sizes in a moment.”

      And indeed, that’s exactly what he does further down the page. He used all that math to arrive at an actual betting spread of $5/$10/$20/$40/$50/$60, as the true count increases from +1 up to +6.

      Now the bad news, about bankroll concerns. The edge in card counting is small, so that means you need a big bankroll to handle the inevitable losing streaks.
      You say that you usually take about $1000 to play, which is probably your trip bankroll, not a lifetime bankroll. You should use a total, or lifetime, bankroll to decide how much you can afford to bet, with the realization that a run of bad luck will put you out of commission until you can raise another trip stake.

      But there is no doubt that $1000, even as just a trip bankroll, is insufficient to safely play a game with a $25 minimum bet. You need to find a lower minimum game. Unfortunately that often means worse conditions and rules. It’s a trade-off. You may have to backcount worse shoe games that have a $5 minimum to find a viable opportunity.

      A little more good news: It is not necessary to readjust your bet sizings constantly. In fact, you can reasonably decide your betting limits for a trip before you go, and don’t worry about them after that. If you’re unlucky, yes, you may run out of money for the trip. But we’re talking trip bankroll here, and your bet sizing should really be based on your total bankroll, which should not see dramatic percentage changes in a single session.

      As for your question 4, about multiplying your bet by the true count, that’s not a bad approach, and it actually is not much different than the GameMaster’s bet ramp from $5 to $60. Can your linear ramp be tweaked for slightly better performance? Probably, but it’s not worth stressing over. Your approach has the benefit of simplicity, and there’s nothing inherently wrong with it.

      Now, on to strategy variations… The three index numbers you mention are by far the most important. Once you are ready to expand your game and use more indexes, search for “Illustrious 18”, and you’ll find the 18 most important numbers. The “I-18” will get you at least 80% of the value of strategy variations. If you want to go further yet, consider my indexes available on these strategy cards:
      (If any readers aren’t sure what I’m talking about, that last link has a brief intro as well.)

      So, the bottom line is… It takes a bigger bankroll to safely tackle the $25 minimum games you are currently playing. You are almost certain to encounter a losing streak in the multiple thousands of dollars occasionally at this game. If you’ve been lucky enough to build that big a cushion first, your bankroll may never look back. If not, well, you’ll be back to raising another stake. The problem with moving down to lower stakes is twofold: One, the games are usually worse, requiring more discipline and bigger spreads. Two, the profit potential is lower in the smaller games, and it’s hard to stay motivated when your hourly earn rate is so low.

      So, it’s time to decide whether you’re willing to down-shift in games, and spend a lot of time grinding for small stakes to build up a bank, or take a risky stab at the higher earning games with the knowledge that any losing streak may wipe you out. As long as you understand the choice, there are good reasons to make either decision.

      • Ploppy Mcplopperson replied:

        Ken is this bet ramp ok? +1 $10 +2 $50 +3 2X$50=$100 +4 2X$75=$150 +5 or higher im maxing at 2X$100. Played at this particular casino for 2-3 months; been doing well with no pit critter sweat.

        • Author Ken Smith replied:

          There’s nothing wrong with that bet ramp if you’re getting away with it. 20:1 will definitely win the money! I like big spreads. Especially if you have the flexibility to travel a bit. And some out-of-the-way casinos are just clueless.

      • Jimbo replied:

        Whoa here. I understand that varying one’s bet raises a red flag that you are probably a card counter. How does one camouflage bet variations to avoid being caught?

  • Jewell Ledwell said:

    I just started blackjack in casinos last week. Thanks for all the tips.

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