Blackjack 40X Double Down

Saw a new side bet today at an off strip casino. Consists of side bet available that can equal up to 10% of your main bet. If you get a double down, you have the option to increase the side bet up to 40X. If you split your hand and receive 2 double downs you can 40X the side bet on each hand.

Example 100.00 hand bet. Can bet up to 10.00 on side bet. No double available or split resulting in a double opportunity you lose the 10.00

If you have a double opportunity or split opportunity you can bet up to 40X the side bet amount.

The only info I can find on this is here

http://www.bigbetgaming.com/40x.html

Figured I would post this as a couple members here had spotted the game during the WOV Spring Fling. Maybe we can get a discussion going on this.

My initial thought is you have an opportunity to double way more frequently than once every 40 hands. More like once every 8-9 hands. How favorable the double is, is another question. This just seems highly exploitable. There are no restrictions as to the dealer up card having to be anything nor do you have to have a hand specific double.

When is the bet paid out?

Quote: MaxPen

My initial thought is you have an opportunity to double way more frequently than once every 40 hands. More like once every 8-9 hands. How favorable the double is, is another question. This just seems highly exploitable. There are no restrictions as to the dealer up card having to be anything nor do you have to have a hand specific double.

Thanks for posting the info. To me, it's complicated, and I need to know more info about the side bet. If I assume the side bet either lets you double or you lose it, then this is definitely a horrible bet...

EV = (AvgDDAdvantage)*(400) + 100*(HE) + (NoDouble%)*(10)

Throwing some 'rough' figures in the mix just to get some numbers flowing... Let's assume your average advantage from doubling down is about 4%, ignoring pushes ( https://www.blackjackinfo.com/double-down-probabilities/ ).

An example from this chart: If you have A-5 against a dealer 5 you'll win 53.2% of the time and lose 46.8% of the time (again, ignoring pushes). So you're looking at a 3.2% edge. I took a rough eyeball of the average advantages and came up with this number, so do believe me when I say, this is a rough estimate...

Also, you should expect to get a DD about a little less than 1 out of 10 hands (9.67%), according to https://www.blackjackinfo.com/knowledge-base/blackjack-general/need-blackjack-double-down-statistics/ . This results in a 90.33% chance of NOT getting a double down.

EV = (.004)(400) + 100(-.005) + (-.9033)(10)

EV = 1.6 + (-.5) + (-9.033)

EV = -7.933... So in the scenario MaxPen provided... where you flat bet $100, $10 on the side bet, then $400 (max) on the double down when you get them... You can expect to lose $7.93 per HAND! The absolute KILLER is that you auto lose the side bet when you don't have a double down (which you only get just under 10% of the time). Max, can you confirm that's all the side bet is? ...an auto loss unless you have a double down hand?

I would think optimal play strategy would have you doubling down on more than the 'traditional' double downs. You would start doubling down on plays that are just slightly negative EV, willing to lose a few cents in EV to save automatically losing the $10 side bet. And you would double these negative return situations for far less than that 40X max. I guess you would double for whatever the minimum is, presumably 1x side bet.

Quote: kewlj

I would think optimal play strategy would have you doubling down on more than the 'traditional' double downs. You would start doubling down on plays that are just slightly negative EV, willing to lose a few cents in EV to save automatically losing the $10 side bet. And you would double these negative return situations for far less than that 40X max. I guess you would double for whatever the minimum is, presumably 1x side bet.

Ha, this would be quite fun to see someone doubling 'just about everything' for the min. I still think the result would be negative, but again that's just a slightly educated guess.

Let's also not forget if the PB see's you doing this (playing not 'normal' blackjack) they can just ask you to leave... which apparently some places do quite frequently =P (more to come in my trip report later this week).

You auto lose the side bet if there is no double down. You can 1-40x the side bet, not the main bet, if there is a double down. There are no restrictions as far as I know on what qualifies as a double down. The bet is complete at end of each hand.

Side bet would be potentially exploitable by counting for aces and small cards which would contribute to the probability of being dealt a double down opportunity, but with an excess of aces and small cards that leaves the player in an unfavorable situation for winning the double down bet.

But .... if EV< -0.2, (such as -0.7933!, which I think is a highly credible estimate) then it is a non-starter.

The advantage on double down bets is usually small - expected value is often (usually) less than +0.1. The largest advantage (I think) is doubling on 6-5 vs a dealer 6 - about 68%, but that is the exception not the rule.

Can I double down on 16 for $1? Double down 12v2 for $1?

Quote: Avincow

Can I double down on 16 for $1? Double down 12v2 for $1?

This is actually a shrewd question. On a double down bet the player is not actually required to double the size of his bet - e.g., in instances in which the player has insufficient chips/funds to double down he can increase his original bet by what he has (by any amount up to doubling his bet). So, can a player declare double down and not augment his original bet (or augment it for only $1) but instead just leave his side bet in play for the double down situation, thereby avoiding the automatic loss of his side-bet?

(Addition on editing). On rereading the posted rules several times it is unclear whether or not the player loses their original sidebet when they do double down. The rules state that the player may add to a double down bet an amount up to 40X the side bet -but this sounds as if the sidebet itself may be forfeited anyway. What happens to the original sidebet when a double down situation occurs?

I am not a 'math guy' so I haven't done the work....I'll leave that to you guys. :) But even if you could manipulate the side bet wager, doubling for the minimum on many slightly negative situations, while doubling for 40x on positive situations, and it worked out mathematically, that the whole 'scheme' ended up being slightly +EV, you are going to run into the same 2 negatives that you do with all side bets. 1.) side bets slows the game to a crawl. Winning pennies by manipulating the side bet will cost you many dollars in lost rounds on the main game. 2.) as Romes alluded to, if you start playing an unusual strategy, where you are doubling on unusual hands and doubling for 1x here and 40 x there, you are going to draw attention. Drawing attention is always a negative in my world. :(

Because of this attention thing, I only have one side bet that I play sparingly, where the side bet becomes profitable correlating to count . It's unusual in that the side bet opportunity takes place during the round of play rather than placing the wager before the round of play. That has the advantage that my side bet is on the felt for a shorter time and I like that. But I treat the side bet just like playing my regular game for longevity concerns. If the count is strong enough that the side bet has become profitable, that will 'trigger' my exit from the game at the next shuffle, just like placing my max bet and showing my spread will trigger my exit at the next shuffle.

Quote: MaxPen

You auto lose the side bet if there is no double down. You can 1-40x the side bet, not the main bet, if there is a double down. There are no restrictions as far as I know on what qualifies as a double down. The bet is complete at end of each hand.

I think I'm not understanding.

If the side bet has been placed (before the cards come out), the player has the option, when doubling, to double the main bet, and double the side bet up to 40x the original side bet?

The side bet is taken by the house if no double is made?

The side bet is taken by the house if the dealer's hand totals higher than the player's hand, but not over 21?

The side bet is taken by the house if the player busts?

The side bet is pushed if the dealer's hand equals the players hand?

The side bet is paid when the player's hand totals higher than the dealer's hand, or the dealer busts?

What happens if the player doubles the main bet, but elects not to double the side bet?

Quote: Dieter

...What happens if the player doubles the main bet, but elects not to double the side bet?

Presumably the side bet is then taken... it sounds like it's either doubled (for up to 40x) or lost.

Quote: Romes

Presumably the side bet is then taken... it sounds like it's either doubled (for up to 40x) or lost.

Correct. I will go sometime this week and clarify everything according to the store offering it.

Quote: MaxPen

Correct. I will go sometime this week and clarify everything according to the store offering it.

Only thing I would be concerned about, MaxPen, is this store, has a reputation for sweating normal card counting action at relatively low limits, so I can't imagine, unusual play on the side bet will go unnoticed. And it's one of those situations where the loss of one property will mean trouble at others. So be careful.

BTW, I played with our blind friend last week. His attitude hasn't changed from his recent experiences. He is still unfriendly and at times unpleasant to be around. Not that this is justification for the sleazy actions of the casino in taking advantage of him and his handicap. I wish we could name that casino publically, but I know we can't.

So, what about the splits, with up to 40x on both hands? Is a split bet increase (beyond what you have to put up to split) just categorically a bad idea, or might those hands (some or all) be worth the bet? Maybe at a reduced amount, since its 1-40, not 40x or lose your bet?

Seems like a huge amount, 40x. Even if it tops out at 4x your base bet (which you've already put up double for, right?), what a huge amount - scary unless I had a really good math eval of it that showed best strategy. Which so far, you guys are indicating it's not going to have one.

My friend, an aggressive black chipper played at this store and tested out the waters of this side bet. He only bet it at positive counts for a chance to double. I told him this was flimsy but he wanted to test it out and use it for cover. There seems to be a high tolerance level so far given that it is still new unlike blasting LL and KB at other stores. He mentioned that he played this store for several hours (i guess blasting the side bet was good cover) and actually won about 5k from the side bet alone. They didn't even seem to care about his action given that he was blasting the side bet.