What does doubling BJ do to 6:5 BJ?

I'm not sure if anyone has run a sim on this yet, I don't believe I have seen anything on it. Once in a great while, usually as a "joke" I will double down on a natural instead of taking my 1.5 to 1 payout on a 3:2 table and "usually" end up with a 2 to 1 because of the double down. Of course this play is almost always called to the floor but I have successfully gotten away with it quite often when warranted, such as a high count with a dealer showing a 4, 5, or 6.

Can someone with the capability please figure out what would happen to the house advantage on a "basic" (use the most common 6:5 single deck table rules here) 6:5 table if you used perfect basic strategy with the exception of doubling down on naturals a follows:

Double all BJ = x.xx% HA
Double BJ against 4, 5, 6 only = x.xx% HA

If there is an advantage here, can someone figure out the index to use to make the play worthwhile?

It would be nice to see this figured out on single deck BJ that only pays 1 to 1 also for obvious reasons.

I may be whizzing in the wind on this one but I hope someone can come up with some real numbers and not just say, "The house edge increases..."

Free beer tomorrow to whoever posts the data.

Sorry I haven't posted in a while, been playing quite a bit more than posting, and my horizons have been broadened, lol.

You can't be serious

A few previous threads with this question:
http://www.blackjackinfo.com/bb/showthread.php?p=3430
http://www.blackjackinfo.com/bb/showthread.php?p=107175
http://www.blackjackinfo.com/bb/showthread.php?p=63239

Thanks Ken!

Ok, looks like the difference is approximately $52.00 on a $100 bet. So just take your BJ and be happy unless you are using some holecarding or spooking strategy then that can make this a real play.

Thanks for the info Ken!

You have never gotten 2 to 1, so re-think!!!


You win on a double down and you are always paid just 1 to 1. Perhaps it is easier to understand if we state this as being paid just 2 to 2. What this means is on a hand where you are already gauranteed a 150% profit, you decide to double your bet hoping to increase your total win by 33% but instead of no risk you risk double your original bet.

In bigger dollars, a dealer in Vegas told me about a player who got a blackjack with a $400 bet and turned an easy $600 win into an $800 loss by doubling. He hit a 9 for 20 only to watch the dealer, who had a 5 up, turn a 6 in the hole and follow it up with a paint.

Play the worst slot machine in the house, play Keno, and play the big wheel, your odds are much better on all of these than doubling a blackjack.

ihate17

Really only 1:1

Thanks for the good word 17. I do understand it is not a real 2:1, just a 1:1 with added risk. I'll put it in my bag of, "only do this as a really stupid play with very little $$ out" tricks.

Doubling a blackjack is like doubling on 11 you will probably win but if you don't it will be devasting to your EV. In beat the dealer Edward Thorp talked about doubling on blackjack but he did it in the 50's and 60's when casinos would deal out 51 out 52 cards in the deck. He would double in blackjack when all there was left in the deck was 10's. You are risking 350% ev if you lose a 150% ev if you tie and only gaining 50% if you win. The odds of winning to losing have to better than 7 to 1 just to break even on the play.

You lost me at this.