Basic BS question

#1
Im sorry if this information is located somewhere else, however my search of the forums didnt turn it up. When you have 12 or 13 and the dealer has a 2 showing I understand you're supposed to hit and I(think) I understand why. My question however is why dont you hit 12 or 13 against a 3? Thanks.
 

positiveEV

Well-Known Member
#2
Because against a 2 and a 3, the EV of hitting a 12 is higher than the EV of standing. With a 13, the EV of standing is higher than the EV of hitting because you have a higher risk of busting.
 
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#4
Myzery87 said:
Im sorry if this information is located somewhere else, however my search of the forums didnt turn it up. When you have 12 or 13 and the dealer has a 2 showing I understand you're supposed to hit and I(think) I understand why. My question however is why dont you hit 12 or 13 against a 3? Thanks.
FIRST - LEARN BS!! (12 vs 2 or 3 = HIT). zg
 
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bj bob

Well-Known Member
#5
BS is no BS

Myzery87 said:
. When you have 12 or 13 and the dealer has a 2 showing I understand you're supposed to hit and I(think) I understand why.
I think you have it backwards here. You hit when you have a 12 and the dealer shows a 2 or 3. This, as Zg said , is basic strategy 101 and should be studied until absorbed like a suntan in Vegas. If the charts seem too overwhelming, just break them down into the major fragments, i.e. First learn the hit/ stand section, then move over to the hard double section and so forth.
To answer your question regarding 13, if you hit a 13 v. 2 you will lose an extra 2 bets/100 and a 13 v. 3 will lose an extra 4 bets/100. Believe us! All the math has already been thoroughly documented and proven, so save yourself mucho tiempo and just memorize the charts.
 

EasyRhino

Well-Known Member
#6
Here's the deal. The deuce gets called a dealer ace because he has nearly equal odds of reaching any possible total (17-21, or bust). The odds are a little higher that he'll bust, but not particularly high.

This means that if you stand on any number lower than 17 vs a deuce, you're probably going to lose.

Now let's say that you have a twelve. You run a substantial risk of busting when you hit, bu the possibility of improving your hand makes it worthwhile.
 
#7
At the casino a while ago, I was sitting beside a guy who, like many other ploppy's, stood on 12 against a 2 or 3 every time. I, of course, hit it, and after hitting it about 5 times, this conversation starts:

Him: Why do you hit that, you should be staying you know?
Me: No, I play basic strategy, and it's a hit.
Him: No, I'm pretty sure it's not a hit. Anything over 11 with the dealer showing 6 or under is always a stay.
Me: Hey dealer, what does your basic strategy card say for a 12 against 2 or 3?
Dealer: It says it's a hit, sir.
Him: Well that doesn't make much sense, the math shows that it's a stay.
Me: Actually, there's about a 2% edge for winning if you hit rather than stay.
Him: Well that's hardly any edge, what's the point?

Then I just stopped talking.
 
#8
Thanks for the info, as many times as I've looked at that chart Im surprised I got that backwards. Is there any place that shows the math or explains it behind the chart? While Im not disputing the accuracy of the information certain things just seem odd to me (splitting 8s against a 9-A). Im using the 8 decks, H17, DAS, No Surrender, Peek chart.
 
#9
Myzery87 said:
Is there any place that shows the math or explains it behind the chart? While Im not disputing the accuracy of the information certain things just seem odd to me...
Its not based on math, per'se - its all based on computer simulation. zg
 

KenSmith

Administrator
Staff member
#10
Actually, it is based on math, not simulation. Each possible drawing combination is examined, and weighted by the appropriate probability. Whichever strategy has the highest expected return is the basic strategy play.

Of course, I don't think that's actually what you were asking. I think what you meant was "Why don't these make intuitive sense?" Well, they just don't.
 

GeorgeD

Well-Known Member
#11
KenSmith said:
Actually, it is based on math, not simulation. Each possible drawing combination is examined, and weighted by the appropriate probability. Whichever strategy has the highest expected return is the basic strategy play.

Of course, I don't think that's actually what you were asking. I think what you meant was "Why don't these make intuitive sense?" Well, they just don't.
Could you say based on math but proven by sinulation?
 

KenSmith

Administrator
Staff member
#12
No, the best way to determine optimal strategy uses combinatorial analysis, not simulation. There's no question of how many hands are necessary to be statistically significant, and no nasty questions about the integrity of the random number generator. Instead, the answer is just calculated outright.
 
#13
KenSmith said:
Actually, it is based on math, not simulation.....the best way to determine optimal strategy uses combinatorial analysis, not simulation. There's no question of how many hands are necessary to be statistically significant, and no nasty questions about the integrity of the random number generator. Instead, the answer is just calculated outright.
Roger that. And on general principal I am partial, likewise, to algebraic-derived indices sans simulation.
BUT it occurs to me that correct BS was ultimately ONLY arrived at via computer simulation. Yes? zg
 

ihate17

Well-Known Member
#14
Why certain basic strategy plays look strange to folks

Myzery87 said:
Thanks for the info, as many times as I've looked at that chart Im surprised I got that backwards. Is there any place that shows the math or explains it behind the chart? While Im not disputing the accuracy of the information certain things just seem odd to me (splitting 8s against a 9-A). Im using the 8 decks, H17, DAS, No Surrender, Peek chart.
I call them underdog plays. Hitting your 12 vs 2 or 3, or the most famous one, splitting your 8's against 9,10, or Ace.
In these cases no matter if you hit, stand or split you are an underdog on the hand. Remember, just because that dealer is showing a 2 does not mean that she has 12 and even if she does there is a very good chance that she will not bust. The math basically shows that by hitting your 12 or splitting your 8's, over time you will lose less money than by staying in both cases(or also taking a hit in the case of the 8's).
So you look at it and say that it does not make sense because I can bust on the 12 or get 2 18's on the 8's and lose anyway, but you will lose less.

The vast majority of people who think they know how to play blackjack seem to follow the most logical parts of basic strategy but do not grasp these reduced negative consequence plays and other plays such as hitting your soft18,and splitting 9's at the proper times.

ihate17
 

SystemsTrader

Well-Known Member
#15
Myzery87 said:
Is there any place that shows the math or explains it behind the chart? Im using the 8 decks, H17, DAS, No Surrender, Peek chart.
Here's the math which will help you understand why you hit instead of stand. As Ihate 17 said these are defensive plays which will still make you a loser, just that you will lose less over the long run.

T,2 vs 2
stand -0.288712
hit -0.252610

9,3 vs 2
stand -0.285771
hit -0.255298

8,4 vs 2
stand -0.285175
hit -0.254479

7,5 vs 2
stand -0.282938
hit -0.253645

T,2 vs 3
stand -0.248340
hit -0.232264

9,3 vs 3
stand -0.247695
hit -0.236468

8,4 vs 3
stand -0.242858
hit -0.233497

7,5 vs 3
stand -0.242053
hit -0.232647
 

MGP

Well-Known Member
#16
zengrifter said:
Roger that. And on general principal I am partial, likewise, to algebraic-derived indices sans simulation.
BUT it occurs to me that correct BS was ultimately ONLY arrived at via computer simulation. Yes? zg
NO. CA is what determines the correct "basic" strategies. Simulations can only confirm.
 
#17
MGP said:
NO. CA is what determines the correct "basic" strategies. Simulations can only confirm.
That almost sounds contradictory. And I thought that it was Thorp's computer-power that revealed SOME of of the errors in the Los Alamos BS... and then it was Braun's even faster computer in '66 that revealed the final mistakes.

Are you saying that I can't simply run a simulation to figure out BS?

Like say 20m hands 88v10 SPLIT, 20m hands 88vs10 STAND, etc.?? zg

Ps - If not, then I'm really showing my ignorance!
 

EasyRhino

Well-Known Member
#18
Where are Smith and Renzey when you need them?!

My understanding is that for computing basic strategy, combinatorial analysis (or as I like to call it: "math I don't understand") will yield the most pure results.

And modern computers make combinatorial analysis much faster than in the adding machine days of the four horsemen.

However, developing effective counting strategies was, as far as I know, impossible without computers.
 

ScottH

Well-Known Member
#19
Using straight math will yield the perfect answers, and simulations will get really close. If you simulate enough hands it will get to the same answer, but like Ken said the best way is math because there is no questions about the program used, how many hands are necessary, etc. If you just look at every combination, then you just know the answer without quesion.
 

mdlbj

Well-Known Member
#20
When I'm sitting at a table and am presented with any given hand at any given count, I know what I'm going to do. Thinking about what percentage of busts, hits etc is a waste of time. Just play BS for the table rules and the correct deviations and you will not have a worry.

It may be a shock to the math jockeys here but, it really does not matter if you win the hand or not because, you know you are playing with the advantage and in the long run, you will come out ahead.

Stomach that and you will reach the next level.
 
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