Doubling down on 20
December 24th, 2017 at 5:29:33 PM
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Hi, I'm wondering what the odds are if a player wanted to double down on hard 20 (hoping to get an ace) on a standard six deck blackjack game.?
The game is uk blackjack so dealer stands on soft 17 and players can double any two cards and split any two cards the same value.
Also wondering how the odds of this double would be expressed as a house edge?
Cheers
The game is uk blackjack so dealer stands on soft 17 and players can double any two cards and split any two cards the same value.
Also wondering how the odds of this double would be expressed as a house edge?
Cheers
December 25th, 2017 at 2:21:33 AM
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You can check it here:
https://wizardofodds.com/games/blackjack/appendix/1/
Slightly depends on the dealer's upcard but the EV for doubling hard 20 is between -1.71 and -1.7 (unit bets)
As for the effect on the house edge, just some rough estimates: we get hard 20 without dealer blackjack about 9% of hands, staying will have about +0.65 EV on average while doubling is -1.705
(-1.705-0.65)*0.09*100% = -21.2%
adds 21% to the house edge... I am now curious what made you wonder about that?
https://wizardofodds.com/games/blackjack/appendix/1/
Slightly depends on the dealer's upcard but the EV for doubling hard 20 is between -1.71 and -1.7 (unit bets)
As for the effect on the house edge, just some rough estimates: we get hard 20 without dealer blackjack about 9% of hands, staying will have about +0.65 EV on average while doubling is -1.705
(-1.705-0.65)*0.09*100% = -21.2%
adds 21% to the house edge... I am now curious what made you wonder about that?
December 25th, 2017 at 4:33:41 AM
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Started off as a stupid joke. I'm a casino dealer and I'll suggest it as a joke to the player, explaining that if they double and get the ace, they will be legendary and have STORIES to tell.
Well, I'm now thinking about it as a little side bet called Crazy Ace ©.
Based on the the odds you have provided, for which I'm thankful, if it wins, the casino can offer a payout of 10 to 1? Don't know. What do you think?
Well, I'm now thinking about it as a little side bet called Crazy Ace ©.
Based on the the odds you have provided, for which I'm thankful, if it wins, the casino can offer a payout of 10 to 1? Don't know. What do you think?
December 25th, 2017 at 5:16:37 AM
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Terribly sorry about this. I'm ok and getting the occasional idea, maths is a mystery to me.
How would these odds be represented as a 1 in ? chance of winning?
How would these odds be represented as a 1 in ? chance of winning?
December 25th, 2017 at 7:22:01 AM
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I propose naming this side bet "Stupid Motherf$$ker".
It costs a dollar per round and pays off when you double and win on a natural 20 or a natural 6.
It costs a dollar per round and pays off when you double and win on a natural 20 or a natural 6.
December 25th, 2017 at 1:12:33 PM
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You could have a sidebet that pays more than 100%, but can only be a certain ratio of your main bet and forces you to break from BS.
Does anything like that exist? As in, it's been through field trials?
Does anything like that exist? As in, it's been through field trials?
Its - Possessive; It's - "It is" / "It has"; There - Location; Their - Possessive; They're - "They are"
December 25th, 2017 at 1:57:44 PM
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Quote: piroukayHi, I'm wondering what the odds are if a player wanted to double down on hard 20 (hoping to get an ace) on a standard six deck blackjack game.?
The game is uk blackjack so dealer stands on soft 17 and players can double any two cards and split any two cards the same value.
Also wondering how the odds of this double would be expressed as a house edge?
Cheers
Don't forget Spanish 21, you can't TIE with that 21 in this game. Tying with 21 is such a bummer.
'Emergencies' have always been the pretext on which the safeguards of individual liberty have been eroded.
December 25th, 2017 at 2:02:58 PM
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Quote: bobbartopDon't forget Spanish 21, you can't TIE with that 21 in this game. Tying with 21 is such a bummer.
Player 21's in Spanish 21 are automatic winners. You're thinking of Double Exposure.
DUHHIIIIIIIII HEARD THAT!
December 25th, 2017 at 2:09:40 PM
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Quote: IbeatyouracesPlayer 21's in Spanish 21 are automatic winners. You're thinking of Double Exposure.
I think you just misread what I wrote, either that or I didn't write it very well. Maybe both, but we're on the same page. Btw, I respect your posts.
'Emergencies' have always been the pretext on which the safeguards of individual liberty have been eroded.
December 25th, 2017 at 3:07:47 PM
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Quote: bobbartopI think you just misread what I wrote, either that or I didn't write it very well. Maybe both, but we're on the same page. Btw, I respect your posts.
I got it now. 😉
DUHHIIIIIIIII HEARD THAT!
December 25th, 2017 at 5:37:06 PM
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Quote: noy2222I propose naming this side bet "Stupid Motherf$$ker".
It costs a dollar per round and pays off when you double and win on a natural 20 or a natural 6.
Casino 5 card poker could claim that title. odds of getting a flush are 1 in 508. Can the player's odds doubling on hard 20 on BJ be worse than this?
December 26th, 2017 at 7:02:33 AM
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Quote: piroukayCasino 5 card poker could claim that title. odds of getting a flush are 1 in 508. Can the player's odds doubling on hard 20 on BJ be worse than this?
Kind of apples-to-oranges comparison, right?
Unless..
96/312 x 95/311 chance of getting a hard 20 in the first place, x 24/310 chance of then getting an ace, for 6 deck. 1 in 137.4267 hands is what I get, apples to apples.
But once you already HAVE 2 tens (6 deck), you have a 7.742% chance of getting an ace to go with it, or 1 in 12.99 hands. Which I would think you knew (1 in 13 cards being an ace).
If the House lost every hand, they wouldn't deal the game.
December 26th, 2017 at 7:52:38 AM
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It could be a free bet.
If a player has a 20, offer to pay some multiple of his existing wager if he hits and gets an ace.
If he busts, he just loses his existing wager.
As a free bet, and with a sufficiently high multiplier, you could get lots of suckers to fall for it while maintaining an obnoxiously high house advantage.
If a player has a 20, offer to pay some multiple of his existing wager if he hits and gets an ace.
If he busts, he just loses his existing wager.
As a free bet, and with a sufficiently high multiplier, you could get lots of suckers to fall for it while maintaining an obnoxiously high house advantage.
December 26th, 2017 at 1:54:58 PM
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Is it 1 in 13 still with six decks?
December 26th, 2017 at 7:07:19 PM
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At the point of possibly hitting a hard 20, the odds of an ace are not exactly 1 in 13, because the only two known cards already in play are both 10-vale cards; i.e., non-Aces. (Or rather at least two non-Ace cards totalling 20? I suppose your hard 20 could include an Ace, but I haven't been thinking of the problem that way.) I think that should make the odds very slightly higher than 1 in 13, perhaps the 1 in 12.99 suggested by BBB (if I am remembering her post correctly without looking back.)
December 27th, 2017 at 1:25:05 AM
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It sounds like a waste of space to me. Someone has a good hand and they want to pay extra to destroy it, I don't think so. Sounds like it would slow down the game. There are better ideas than this to investigate.
I am a robot.
December 27th, 2017 at 1:35:26 AM
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Seems Iike this would appeal to someone that plays blackjack like poker. i.e. If they can't raise they fold. There is maybe a few players out there that want to and will double everything. Saw one regularly in the Cannery couple years ago. I think he hated money.😳
December 27th, 2017 at 6:12:19 AM
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Assuming a fresh shuffle and the only exposed cards are 2 ten-value cards and the dealer's upcard (which we'll assume is not an ace), there are 24 Aces and 285 non-Ace cards unseen in a 6-deck shoe. So, odds for an Ace = 24 in 309, or 1 in 12.88.
Further, if the dealer's upcard is an Ace (or if your 20 consists of A-9), then your odds would be 1 in 13.43. And if you had A-9, and the dealer also had an Ace, the odds would be 1 in 14.05.
Of course, the odds will change with each card dealt. I'm no counter, but I would think this type of bet would be easily vulnerable to someone just counting aces.
Further, if the dealer's upcard is an Ace (or if your 20 consists of A-9), then your odds would be 1 in 13.43. And if you had A-9, and the dealer also had an Ace, the odds would be 1 in 14.05.
Of course, the odds will change with each card dealt. I'm no counter, but I would think this type of bet would be easily vulnerable to someone just counting aces.
"Dealer has 'rock'... Pay 'paper!'"
December 27th, 2017 at 8:38:32 AM
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The only way you can make a 2-card hard 20 is with two 10-value cards. Since most casinos do not allow doubling on 3+ cards there are no other possible combinations for this scenario under normal rules (and A+9 is a soft 20, which although still a bad play to double is much safer than doubling on a hard 20).
May 11th, 2018 at 2:13:58 PM
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Thank you, everybody, for all your help, guidance and amusement.
May 11th, 2018 at 4:58:30 PM
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well there is a 1 in 13 chance u win and a 12 in 13 chance u lose... u do the math
May 11th, 2018 at 5:40:11 PM
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Quote: BlackjackGuy123well there is a 1 in 13 chance u win and a 12 in 13 chance u lose... u do the math
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May 11th, 2018 at 8:06:13 PM
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There was a game at Ameristar St. Charles called Double Back Blackjack. Not sure if the Wizard covered this game, can not find it.
But people doubled their 20s a lot in hope to double back for a good hand.
But people doubled their 20s a lot in hope to double back for a good hand.
May 15th, 2018 at 11:44:47 AM
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I never got this hand in FreeBet: you have split your 9's and on the Free portion got an Ace - if I recall correctly you then real money double the 9A. (There was another game you also did this but I forget the exact details but probably knew the dealer had a stiff hand.)Quote: Kellynbnf...A+9 is a soft 20, which although still a bad play to double is much safer than doubling on a hard 20..
August 19th, 2019 at 12:09:08 PM
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Found this forum thru Google as I thought it was one of the worst plays in blackjack and yet saw it not just once but twice happen in real live action in a casino. Even more amusing is both of them got their Aces and won.
Both were women and I asked one of them why??? and she said you can't win if you don't take risks.
Not surprisingly, she was done after a few more hands. I think, the house edge on these games are even higher than what the math says since human stupidity is not factored in.
Disclaimer: both instances happened on virtual blackjack machines (smiling dealer is on a big screen) so dealer can't help them realize how stupid the risks their taking.
Both were women and I asked one of them why??? and she said you can't win if you don't take risks.
Not surprisingly, she was done after a few more hands. I think, the house edge on these games are even higher than what the math says since human stupidity is not factored in.
Disclaimer: both instances happened on virtual blackjack machines (smiling dealer is on a big screen) so dealer can't help them realize how stupid the risks their taking.
