soft doubling 19 vs 7 and 8: plausable?

[Ferretnparrot]

Iv been very curious about deviations ivolving mostly soft 19s but i dont think its too far fecthed to think that soft 20s may be included in this also.

Its been an established fact that at certain counts it is beneficial to double 9 vs 7 and 8 however a soft 19 has no index numbers for soft doubling above 6 i find this curious as all of the final hands would be the same as doubling a 9 except for when you draw a 2 it would give you a total of 21, so doubling a soft 19 will give you better chances of drawing to sums of 21 and the exact same chances of every other hand that you would get for doubling a hard 9, all while the same math applies to the dealers showing card. I understand that 19 is a moderatly strong hand not to be touched but its known that 18 will lose more hands than it wins, and 19 is only one above that, i dont think the idea that there may be a playable index number for doubling soft 19 against a 7 or 8 is too far fetched, posibly even for soft 20 also.

Does anybody have the tools to figure that out?

Soft 18s??

 

[Sonny]

I checked a few of my index generators but they don’t list this play. The EV charts for that play show that you will win twice as much if you stand than if you double A,8 vs. 7:

http://www.bjmath.com/bjmath/ev/ev.htm (Archive copy)

The majority of cards will ruin that hand. Since you already expect to win, why ruin it?

-Sonny-

 

[Ferretnparrot]

Im not talking about the correct play, im talkign about the count at which doubling becomes the correct play, i see its relevant to a hard nine where the correct play is to hit and not double, but at high counts doubling becomes the correct play.

 

[Sonny]

I would imagine that the count would have to be ridiculously high to make doubling A,9 vs. 7 a smart play. The fact that you are breaking a potentially winning hand in order to make this play and you already have a max bet on the table would shoot the index several points higher on a risk-adjusted basis as well.

Basically, it’s a count that you may never see in your life and the gain would be so small that it would make the play almost useless. It might happen, but it won’t really matter if you miss the opportunity.

-Sonny-

 

[jack.jackson]

Plausible yes,Advisable no

It really depends on how high the count is. But at extremely high counts some of the following plays are mathematical correctD7vsbust,8vs2,7,DDS21,DD,A6,A7,A8,A9,vs7:A8vs7,8,:A9vs789 and a few Xtra splits. I forgot which ones.

Note: Usually, it would take 1/2 or even 1/4 deck remaining to reach some of these extreme levels. Oh ya, split X,s on 789,A

 

[Automatic Monkey]

Iv been very curious about deviations ivolving mostly soft 19s but i dont think its too far fecthed to think that soft 20s may be included in this also.

Its been an established fact that at certain counts it is beneficial to double 9 vs 7 and 8 however a soft 19 has no index numbers for soft doubling above 6 i find this curious as all of the final hands would be the same as doubling a 9 except for when you draw a 2 it would give you a total of 21, so doubling a soft 19 will give you better chances of drawing to sums of 21 and the exact same chances of every other hand that you would get for doubling a hard 9, all while the same math applies to the dealers showing card. I understand that 19 is a moderatly strong hand not to be touched but its known that 18 will lose more hands than it wins, and 19 is only one above that, i dont think the idea that there may be a playable index number for doubling soft 19 against a 7 or 8 is too far fetched, posibly even for soft 20 also.

Does anybody have the tools to figure that out?

On the other hand, doubling a soft 19 also gives you a much higher chance of getting a 14 or a 16 than if you stand. Then what? I suppose if you know all the cards left were aces and tens it would be the right play. But if there are any low cards at all left, if you get one you are screwed. If the dealer gets one he gets to draw again.

In general, you only want soft doubles in situations where the dealer has a high chance of busting. That's why you do more soft doubles in H17 games than S17 games; in H17 when you get a stiff and the dealer has a soft 17 he hasn't beat you yet.

 

[davidpom]

Hitting 19 (even soft) would be suicidal enough (i.e. there's only 2 cards that could actually improve your score - the others would simply leave it as is (pictures) or make it worse) for most hands in blackjack I would think.

Doubling this hand would seem insane, on that basis.

Is it plausible to double? sure. But is it wise? I don't think so, unless you've got an EXTREMELY high count - and even then, I'd be personally reluctant.

I guess what will dictate things to some extent is your playing style. If you're a particularly aggressive player and happy to take higher risk, then double your soft 19 anytime the dealer shows an 8 or below (when the count dictates that). It's equivalent to splitting your tens against a dealer 9 or below. You won't catch me doing it personally. Yes, at the time of hitting you do have an edge by 1 or 2 points (or more or less depending on the count at the time), but as you'll likely end up hurting your hand more often than helping it, why do it at all? And why give the casino double the cash?

 

[Ferretnparrot]

I thought of this because i was playing a few weeks ago i saw a true count of +12 and i had this hand i really wondered and didnt double it but i still want a number so next time it happens ill be prepared. I wont be satisfied untill i get a number.

 

[EasyRhino]

For the record, doubling A,8 vs. 5 or 6 is a fairly "standard" index play in high counts.

But there's a big difference between a dealer's upcard being 6 or 7.

 

[k_c]

Im not talking about the correct play, im talkign about the count at which doubling becomes the correct play, i see its relevant to a hard nine where the correct play is to hit and not double, but at high counts doubling becomes the correct play.

Using my old infinite deck analyzer, I get a Hi-Lo Index of about +17 for A-8 versus 7. In general infinite deck indices usually turn out to be reasonably close to published indices.

k_c

 

[Ferretnparrot]

Wow thats really hi but thats awsome to know thanks kc

 

[jack.jackson]

Using my old infinite deck analyzer, I get a Hi-Lo Index of about +17 for A-8 versus 7. In general infinite deck indices usually turn out to be reasonably close to published indices.

k_c

Hey k_c do you have a number for A9 vs A? Im guessing +23

 

[zengrifter]

I checked a few of my index generators but they don’t list this play. The EV charts for that play show that you will win twice as much if you stand than if you double A,8 vs. 7:

http://www.bjmath.com/bjmath/ev/ev.htm (Archive copy)

The majority of cards will ruin that hand. Since you already expect to win, why ruin it?

-Sonny-

Revere had indices for those with his two RAPCs. He used extreme indices like those to argue the sophistication of his advanced systems. zg

 

[k_c]

Hey k_c do you have a number for A9 vs A? Im guessing +23

I get double >+23 for S17, double >=+23 for H17. Pretty unlikely to see a count that high though.

k_c

 

[Ferretnparrot]

I get double >+23 for S17, double >=+23 for H17. Pretty unlikely to see a count that high though.

k_c

well using the hi low you cant get a tc higher than 20 as there would be no more small cards left to remove!

 

[Cardcounter]

Can it be mathimatically correct?

You asked if doubling a soft 19 vs a 7 or an 8 can be mathamatically correct yes it can but only in extreme situations such as you keep carefull track of the cards and realize that there are only 10's left in the deck which mean that the dealer has 17 or 18 and that you will have a 100% chance of drawing a 10 giving you hard 19! That would only be possible in a 1 deck with really good penetration a game that is really hard to find! In burning the tables the author told how he got kicked out for doubling down on a 5 because he knew that all the rest of the cards in the deck where 10 value cards and that the dealer was going to bust after that hand the pit boss came over took the deck spread it over the table and saw that they where all tens and said sir you can no longer play blackjack here.
In my opinion it is either a really stupid play which would be the case if more than just 10's existed or an extremely advanced play!

 

[jack.jackson]

Revere had indices for those with his two RAPCs. He used extreme indices like those to argue the sophistication of his advanced systems. zg

Did you use the 17 point count(Ace reckoned) "72" or his 14 point coint (non-reckoned)APC, "74"

 

[k_c]

well using the hi low you cant get a tc higher than 20 as there would be no more small cards left to remove!

If remaining cards consisted of nothing but tens and aces, true count would be +52. +52 is the max Hi-Lo true count possible.

However, in my infinite shoe method I assume the probability of drawing a 7, 8, or 9 remains constant and equals 1/13 so true count can be a maximum of +40 (10/13 tens and aces, 3/13 sevens, eights and nines.)

k_c

 

[QFIT]

When you are talking about such an oddball index, the value can change substantially depending on penetration and exactly how you go about calculating the TC. The below chart is for 5/6 penetration with half-deck estimation for the first four decks and quarter-deck estimation for the last two decks. This resulted in a +18 index. But I got a +21 index with a 4.5/6 penetration and half-deck estimation.