Double-Up Blackjack Variation

Just ran across a new variation. Plays like a typical Vegas shoe game--6 decks, dealers stands H17, Double any 2, DAS, split 3 times except Aces with the following wrinkles. In addition to the normal double bet you also have the option to "double-up" which is an additional bet equal to the original but without taking an additional card. You can also do this after splitting. For example, if you split Aces and got a face card on each you could then double your bet on each or your 21s. You must win this additional bet, dealer takes ties. To make up for this gift to the player the dealers 16 (hard or soft) pushes with all players hands except 21 (won by player). Anybody have the software to figure house advantage on this game? On what hands should you "double up"? What are the variation to basic strategy? It seems to me that this game should be very vulnerable to counting with every increase in the true count adding more than usual to player advantage. I did pretty well against it using Hi-Lo.

I assume if a dealer 16 pushes with all hands, that the dealer stands on 16 AND 17 (or just hits soft 17?).

Quote: thecesspit

I assume if a dealer 16 pushes with all hands, that the dealer stands on 16 AND 17 (or just hits soft 17?).

Here's a good YouTube video explaining the game. I see printed on the felt that the dealer hits soft 17. However, the dealer stands on any soft or hard 16.

And here is a report from Score Gaming's website also explaining the rules and reporting the house edge, which is very low at 0.313%!

An infinite-deck model shows the playing strategy is very similar to the regular H17 game, and Hi-Lo would be adequate for counting it. And here is the double-up strategy: Always double-up 21 and 20. Double-up 19 vs 2-8. Double-up soft 18 vs 7 and hard 18 vs 5 and 7.

Sorry for resurfacing this thread but I played this game last weekend and found it really enjoyable. It's been in Stockton for some time now.
I had a quick look at a strategy and came up (infinite deck) with this (where you've split Aces use the hard total to decide whether to Double Up your resulting score). This tables assumes UK rules except Double Up bets don't lose against BlackJack. Also you can re-split as many times as you like, which may be why my figure is slightly lower than that above.
NB Stockton does not hit soft 17, so I used this table.

		A	2	3	4	5	6	7	8	9	10
HARD Hit/St/DD/DU	21	DU	DU	DU	DU	DU	DU	DU	DU	DU	DU
	20	DU	DU	DU	DU	DU	DU	DU	DU	DU	DU
	19	DU	DU	DU	DU	DU	DU	DU	DU	-	-
	18	-	-	-	DU	DU	DU	DU	-	-	-
	17	-	-	-	-	-	-	-	-	-	-
	16	H	-	-	-	-	-	H	H	H	H
	15	H	-	-	-	-	-	H	H	H	H
	14	H	-	-	-	-	-	H	H	H	H
	13	H	-	-	-	-	-	H	H	H	H
	12	H	H	H	-	-	-	H	H	H	H
	11	H	D	D	D	D	D	D	D	D	H
	10	H	D	D	D	D	D	D	D	H	H
	9	H	H	H	D	D	H	H	H	H	H
	8	H	H	H	H	H	H	H	H	H	H
SOFT Hit/St/DD/DU	11	du	du	du	du	du	du	du	du	du	du
	10	du	du	du	du	du	du	du	du	du	du
	9	du	du	du	du	du	du	du	du	-	-
	8	h	-	d	d	d	du	du	-	h	h
	7	h	h	h	d	d	d	h	h	h	h
	6	h	h	h	h	d	h	h	h	h	h
	5	h	h	h	h	d	h	h	h	h	h
	4	h	h	h	h	d	h	h	h	h	h
	3	h	h	h	h	h	h	h	h	h	h
Split	10	-	-	-	-	-	-	-	-	-	-
	9	-	X	X	X	X	X	X	X	X	-
	8	H	X	X	X	X	X	X	X	X	H
	7	H	X	X	X	X	X	X	H	H	H
	6	H	H	X	X	X	X	H	H	H	H
	5	H	D	D	D	D	D	D	D	H	H
	4	H	H	H	H	H	H	H	H	H	H
	3	H	H	H	X	X	X	X	H	H	H
	2	H	H	X	X	X	X	X	H	H	H
	A	X	X	X	X	X	X	X	X	X	X

This table same except dealer hits Soft 17 (but not Soft 16!)

		A	2	3	4	5	6	7	8	9	10
HARD Hit/St/DD/DU	21	DU	DU	DU	DU	DU	DU	DU	DU	DU	DU
	20	DU	DU	DU	DU	DU	DU	DU	DU	DU	DU
	19	-	DU	DU	DU	DU	DU	DU	DU	-	-
	18	-	-	-	-	DU	-	DU	-	-	-
	17	-	-	-	-	-	-	-	-	-	-
	16	H	-	-	-	-	-	H	H	H	H
	15	H	-	-	-	-	-	H	H	H	H
	14	H	-	-	-	-	-	H	H	H	H
	13	H	-	-	-	-	-	H	H	H	H
	12	H	H	H	-	-	-	H	H	H	H
	11	H	D	D	D	D	D	D	D	D	H
	10	H	D	D	D	D	D	D	D	H	H
	9	H	H	H	D	D	H	H	H	H	H
	8	H	H	H	H	H	H	H	H	H	H
SOFT Hit/St/DD/DU	11	du	du	du	du	du	du	du	du	du	du
	10	du	du	du	du	du	du	du	du	du	du
	9	-	du	du	du	du	du	du	du	-	-
	8	h	-	d	d	d	d	du	-	h	h
	7	h	h	h	d	d	d	h	h	h	h
	6	h	h	h	h	d	h	h	h	h	h
	5	h	h	h	h	d	h	h	h	h	h
	4	h	h	h	h	d	h	h	h	h	h
	3	h	h	h	h	h	h	h	h	h	h
Split	10	-	-	-	-	-	-	-	-	-	-
	9	-	X	X	X	X	X	X	X	X	-
	8	H	X	X	X	X	X	X	X	X	H
	7	H	X	X	X	X	X	X	H	H	H
	6	H	H	X	X	X	X	H	H	H	H
	5	H	D	D	D	D	D	D	D	H	H
	4	H	H	H	H	H	H	H	H	H	H
	3	H	H	H	X	X	X	X	H	H	H
	2	H	H	X	X	X	X	X	H	H	H
HE=0.2628%	A	X	X	X	X	X	X	X	X	X	X

I finally got around to analyzing this game. My numbers don't agree with Charlie's and we're trying to find our point of departure, but I'm pretty sure it has to do with the peeking rule. Please visit my new page on Double Up Blackjack and let me know what you think. As usual, all questions, comments, and especially corrections are welcome.

Quote: Wizard

... corrections are welcome.

The two tables of "strategy after splitting aces, when the only options are to stand or Double Up" both have the same title, "Dealer Stands on Soft 17." From the previous information on the page, the reader will know that the table on the left should be "Dealer Hits on Soft 17."

So, if a dealer hits to 16, and a player Doubled Up there 20. Does the main wager and the Double Up wager push? Or does the Double Up wager lose?

In your analysis at WoO you say “The effect of the dealer standing on a soft 17 is worth 0.43% the player's way, according to my calculations.” Does this make the game +0.11% (with hit soft 17 being -0.32%), or are you saying it is +0.43% overall? I wanted to be sure I was interpreting this correctly. Thanks!

Quote: kuma

In your analysis at WoO you say “The effect of the dealer standing on a soft 17 is worth 0.43% the player's way, according to my calculations.” Does this make the game +0.11% (with hit soft 17 being -0.32%), or are you saying it is +0.43% overall? I wanted to be sure I was interpreting this correctly. Thanks!

My interpretation is that the rule S17 is worth .43% to the player. So if the game is -.32% + .43% then the game would be +.11% with a player advantage (using perfect strategy).

This game has an unusual aspect. The Double UP bet is lost if you tie the dealer even though your original bet is a push.

What follows is a rambling game theory discussion
Now consider the case when you are dealt a hard 20 and dealer has a 10. This happens about 2.85% of the time from a fresh shoe - the most commonly occurring hand in BJ.

Let's say Dealer checks for BJ and gestures for you to act. Wizard's strategy calls for you to DOUBLE UP your bet (which I agree with.)

But isolate the DOUBLE UP wager and consider. The dealers other card is not an Ace, because that would be BJ. If its a Ten-valued card (T,J,Q or K), you lose the DOUBLE UP wager! Damn! If its a 7,8, or 9 you win the DOUBLE UP wager. If its a 6 you push the DOUBLE UP wager. And if its a 2,3,4 or 5 it depends upon the third card drawn by the dealer (and on additional cards as needed). You will tie when any of those hands make a 16, and lose when they don't make 16 and do make a 20 or 21.

I've been too busy and lazy to do the math, but over all I think that the DOUBLE UP/STAND decision on 20v10 is a surprisingly close call -maybe an EV of +0.14 for DOUBLE UP. It therefore may be possible that 20v10 could be an index play (STAND when the deck is rich in Tens and, ideally, when its depleted in 7,8,and 9s).* Just kinda cute that the most frequently occurring hand is so affected by this unusual rule. And that the DOUBLE UP wager on 20v10 has a bit less benefit than one might initially think.

* I don't believe such an index play is of anything but theoretical interest. But I do note that that whenever the TC is positive and high, the 20v10 hand should occur more frequently than 2.85%. Also, given a high positive TC the expert player will have made higher wagers, thus increasing the potential significance of a DOUBLE UP index play on 20v10. Just saying.

Quote: gordonm888

* I don't believe such an index play is of anything but theoretical interest. But I do note that that whenever the TC is positive and high, the 20v10 hand should occur more frequently than 2.85%. Also, given a high positive TC the expert player will have made higher wagers, thus increasing the potential significance of a DOUBLE UP index play on 20v10. Just saying.

This is an odd hand. At low counts the dealer may draw to 20 and 21 more frequently. At high counts the dealer may just flip another 10 (with more money at risk, as you mention). I think there are a number of index plays that would be of great interest as it relates to this double-up option, including hands other than 20 vs 10, although I agree this one is especially perplexing without the data. I was surprised basic strategy was to double-up 20 vs 10. Some of these double-up possibilities just are not real intuitive, and hard to guess at (deviate from basic strategy) without having firm indices. It would be very interesting to see.

Does anyone have any idea what it is worth to the player if the Double Up bet pushes and does not lose when the player and dealer tie? 6 deck CSM h17. Thanks.

The house edge calculated by Charles Mousseau of 0.313%. It doesn’t specify if it was ENHC?
If it was not ENHC, then is it just a case of adding the 0.11% penalty cost of ENHC rule to the 0.313% HE?

Quote: PsychicSpy

Does anyone have any idea what it is worth to the player if the Double Up bet pushes and does not lose when the player and dealer tie? 6 deck CSM h17. Thanks.

I realize this is a somewhat old post, but in general,

The push should not change the HE at all. This is because the incidence of a push, using Optimal Strategy, has been calculated into the HE, at a rate it should occur over the long run.

Quote: Jacblacc911

The house edge calculated by Charles Mousseau of 0.313%. It doesn’t specify if it was ENHC?

Sorry, I don't know whether his calculation included ENHC or not.

Quote:

If it was not ENHC, then is it just a case of adding the 0.11% penalty cost of ENHC rule to the 0.313% HE?

I would think that is correct. It's a blackjack game, the side bet doesn't change the dealing of it (such as making the dealer take an extra card sometimes to resolve the sidebet, that they wouldn't take to complete their bj hand). So you should be able to simply add that factor, if it wasn't originally calculated to he dealt with ENHC.

For the Wizard:

In point number 6 of your rules to this game in question, you state:

‘’In the UK, the dealer does not take a hole card. However, if the dealer gets a blackjack, the player will only lose his original wager and any other bets he lost due to splitting and then busting. The player will not lose any additional wagers from doubling, splitting (except for busted hands after splitting), or Double Upping’’

Standard UK rules almost always includes ENHC where the player will lose all bets, splits and doubles against dealer BJ. Therefore it is common practice to NOT split AA vs Ace, NOT double 11 vs Ace and NOT double 11 vs 10 (except at the index).

Therefore does your point at number 6 refer to Non ENHC rule (dealer BJ doesn’t take all)?
And if so, your HE calculation of 0.32% for this game is WITHOUT the ENHC rule?

Further, if I knew the various advantages of other specific rules, for example: late surrender (0.08) or RSA (0.07), can I just adjust the HE accordingly?

RSA is actually worth about .14% as you're swapping an AA for two (or more) chances to both get better hands and if you do then DoubleUp.

Double Up Blackjack is now on field trial at Binion's. These days Binion's is not known for its good payouts but the game's developer, Score Gaming, is still showing the Mousseau analysis with an HE of 0.313% (assuming perfect play). If true, it would be worth memorizing the WOO charts and checking it out.

The trial ends on 09/15/19.

Is Double UP BJ currently played anywhere within the US?

Question on rules:
Is the ability to Double UP restricted to only 2 card hands? e.g. if you have a 7-5v7 and hit it and draw an 8 to make 20, are you then allowed to double up your 3-card 20?

Yes, I know for sure it is in Michigan, California, and has a few Vegas installs. From operators I have spoken to, it does very well where it has been placed. The "double up" is restricted to 2-card hands 20 or less.