Avoid Single-Deck 6-to-5 blackjack Like the Plague

Up and down the Las Vegas strip, some single-deck blackjack games are beginning to pop up again. They're often advertised with a beckoning "hook" such as "The good old days are back", or some such thing.

There's one huge problem with the game this time around, though, and that is – blackjack pays only 6-to-5 odds rather than 3-to-2! This means if you bet $10 and are dealt a blackjack, the dealer pays you just $12 rather than the customary $15.

If that sounds like no big deal, understand that, on average, you'll be dealt a natural blackjack once every 21 hands. Even at a crowded table, you'll get in about 63 hands per hour. So if you're dealt your fair share of three blackjacks during that time, the house will short you by $9 per hour. For a $10 bettor, that's huge.

Blackjack is such a close game that the house advantage is usually measured in tenths of a percent. But 6-to-5 for blackjack costs you an extra 1.4% all by itself.

Does the fact that the game is played with only a single deck make up for it? Not even close. If it were a regular six-deck shoe with 3-to-2 blackjacks, a $10 bettor's disadvantage from playing with those five extra decks would earn the house about $3.50 after 63 hands. But taking away $9 for three blackjacks during that same time period makes the single-deck game much worse.

A reader of this column wrote me to ask about ways to compensate for the short blackjack payoff in this game. On a recent visit to Vegas, he and his friends complained to the blackjack dealer about the rule. She advised them to double down on blackjack and to take insurance on blackjack against a dealer's Ace as a countermeasure. What about this strategy? Are these good moves?

The answer is, don't do either unless you're mad at your money! Let's examine these plays one at a time.

Doubling on B/J: If the dealer doesn't have an Ace up and you just take the 6-to-5 payoff, you're making an automatic profit of 120% on your bet. Now if you double down, you're in effect, doubling with 11. You might win double your bet – and you might lose double. But the real question is, how much do you average?

It turns out that doubling will net you a mere 40% average profit on your original bet. That is, you'll win two bets 60 times and lose two bets 40 times out of 100, after adjusting for the occasional push. Where doubling down on 11 is normally a strong play, it's nowhere near as strong as being paid a 120% profit. So doubling down on blackjack would send you to the poor house even quicker.

Insuring a B/J: Paying 6-to-5 on blackjack is such a ripoff that in most games of this type, the house won't even allow you to take even money against an Ace up. If they did, you'd make a guaranteed 100% profit on the hand every time.

So how much would you average if you just took your chances with your blackjack? Letting the chips fall where they may, you'll win $12 when she doesn't have it and push when she does for an 83% average profit. That's why they won't give you even money here – which in a regular game would be a sucker play.

But you could still go around the back door just by taking Insurance. That way, your $10 bet will net $7 when the dealer doesn't have a 10 in the hole, and $10 when she does have it. Problem is, that works out to only a 79% average profit.

Therefore, you do even worse by taking Insurance on your blackjack. And it works out that way because Insurance is not a bet on your hand at all, but a bet on the dealer's hand – and a bad bet at that.

So then, in the 6-to-5 single deck blackjack game, avoid doubling down on blackjack and avoid taking insurance on your blackjack. In fact, just avoid the game altogether.