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  #1  
Old March 20th, 2007, 12:18 AM
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Automatic Monkey Automatic Monkey is offline
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Default Blackjack Switch Basic Strategy Research

Two basic strategies for this game can be found on Arnold Snyder's Blackjack Forum Online site:
http://www.blackjackforumonline.com/...icstrategy.htm

And another one by "The Wizard of Odds" Mike Shackleford can be found here:
http://wizardofodds.com/blackjackswitch

Both differ from standard H17 strategy, and there are minor disagreements between the two. Time to monkey around with it.

The reason BJ Switch strategy differs from standard BS is the push-on-dealer-22 rule. It's hard to visualize how this would make a difference, but apparently it does. So I used my CVData simulator to find an ideal basic strategy.

Methodology:

First, I programmed the push-on-22 rule into a CVData sim, by calling it a negative bonus, where if the player doesn't bust and the dealer busts with 22, the player pays his win back to the house. What an ugly rule! Then I applied the brute-force method of deducing plays. It works like this- you start with the hit-or-stand 16 plays, have two players playing agains the dealer, with the only difference being one always hits on 16, and one always stands on 16. By subtracting the resulting win rates for each player on the 16 plays, you can determine against what dealer upcard it is better to hit or to stand. Then you run another sim for the 15's and the 14's, down to the 12's. This is arduous but necessary.

Once you have the correct basic strategy for hit-or-stand, you do the same thing with the hard and soft doubles. You can do these all at once, just one sim. Finally, you run another sim for the splits. At this point you have enough information to provide a complete basic strategy for the game.

Note: these results do not take into account the benefit of switching! That's a whole different topic, but it should be independent of the way you play each hand after you have switched, which is the purpose of a basic strategy. I ran a sim comparing the Monkey Basic Strategy vs. the Bishop Basic Strategy, the Wizard Basic Strategy, and standard H17 multideck Basic Strategy.

Here are the results:
Code:
Strategy	Advantage	SD/100 hands	Effect of dealer push-22 rule
Monkey BS	-9.170%	          10.70	                  -6.111%
Wizard BS	-9.337%	          10.24	                  -6.090%
Bishop BS	-9.370%	          10.21	                  -6.035%
Straight H17 BS	-9.246%	          10.83             	  -6.267%
The actual strategy does make some changes for the push-22 rule but not as many as the other two strategies do. Here is it:

Code:
Blackjack Switch- LV rules- 8D
	Hard Hit/Stand- Dealer’s Card
	2	3	4	5	6	7	8	9	10	A
16	S	S	S	S	S	H	H	H	H	H
15	S	S	S	S	S	H	H	H	H	H
14	S	S	S	S	S	H	H	H	H	H
13	H	S	S	S	S	H	H	H	H	H
12	H	H	H	S	S	H	H	H	H	H
Always hit on 11 or less, always stand on 17 or more.H= Hit     S= Stand     
	Hard Double- Dealer’s Card
	2	3	4	5	6	7	8	9	10	A
11	D	D	D	D	D	D	D	D	D	H
10	D	D	D	D	D	D	D	D	H	H
9	H	D	D	D	D	H	H	H	H	H
8	H	H	H	H	H	H	H	H	H	H
Never double on 12 or more, never double on 7 or less.D= Double     H= Hit     
	Soft Double and Soft Hit/Stand- Dealer’s Card
	2	3	4	5	6	7	8	9	10	A
A9	S	S	S	S	S	S	S	S	S	S
A8	S	S	S	S	D	S	S	S	S	S
A7	S	D	D	D	D	S	S	H	H	H
A6	H	D	D	D	D	H	H	H	H	H
A5	H	H	D	D	D	H	H	H	H	H
A4	H	H	D	D	D	H	H	H	H	H
A3	H	H	H	D	D	H	H	H	H	H
A2	H	H	H	H	D	H	H	H	H	H
D= Double    H=Hit   S= Stand   
	Split- Dealer’s Card
	2	3	4	5	6	7	8	9	10	A
A,A	S	S	S	S	S	S	S	S	S	S
10,10	X	X	X	X	X	X	X	X	X	X
9,9	X	X	S	S	S	X	S	S	X	X
8,8	S	S	S	S	S	S	S	S	X	X
7,7	X	S	S	S	S	S	X	X	X	X
6,6	X	X	S	S	S	X	X	X	X	X
5,5	X	X	X	X	X	X	X	X	X	X
4,4	X	X	X	X	X	X	X	X	X	X
3,3	X	X	X	S	S	S	X	X	X	X
2,2	X	X	X	S	S	S	X	X	X	X
S= Split   X= Don’t split
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  #2  
Old April 5th, 2007, 01:38 PM
phantom007 phantom007 is offline
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Default Nice Study......

I had wondered where you went after CC.com just seemed to vanish one day.
Good Cards!

ph007.
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  #3  
Old April 5th, 2007, 04:00 PM
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halcyon1234 halcyon1234 is offline
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Wouldn't it be easier to write a recursive algorithm for this? Loop through each possible player hand, and for each hand, test each dealer upcard, and for each dealer upcard, test each dealer downcard, and for each dealer downcard, test each possible next card (or stand or bust), and for each next card, test the next card, etc, etc.

That way you'll get an EXACT count of, for each have vs. upcard, how many wins/lose/pushes will come from it.
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  #4  
Old April 5th, 2007, 07:42 PM
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Automatic Monkey Automatic Monkey is offline
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Quote:
Originally Posted by halcyon1234 View Post
Wouldn't it be easier to write a recursive algorithm for this? Loop through each possible player hand, and for each hand, test each dealer upcard, and for each dealer upcard, test each dealer downcard, and for each dealer downcard, test each possible next card (or stand or bust), and for each next card, test the next card, etc, etc.

That way you'll get an EXACT count of, for each have vs. upcard, how many wins/lose/pushes will come from it.
Easier, hell no! It took me just a couple of hours to do it on a sim. What you're proposing is a combinatorial analysis, accurate for sure but not easy. It took a lot of work to develop the first BS for blackjack using such methods.
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  #5  
Old April 6th, 2007, 01:23 AM
aka23 aka23 is offline
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I added a blackjack switch decision calc to my website a few days ago at http://www.beatingbonuses.com/bjscalc.htm .

I noticed that the switching decisions differ in some cases from the calc on Wizard of Odds at http://wizardofodds.com/blackjackswitch . I believe the reason for this is the Wizard of Odds calc assumes an infinite deck and uses EVs before the dealer peaks for blackjack. Note that the EVs used in the Wizard of Odds calc are not the one in the table listed on the site, which assume 8 decks and are after dealer peaks for BJ.
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  #6  
Old April 6th, 2007, 10:13 AM
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Sonny Sonny is offline
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Quote:
Originally Posted by phantom007 View Post
I had wondered where you went after CC.com just seemed to vanish one day.
Good Cards!

ph007.
Welcome ph007! And congratulations on your POM. Now I’m looking forward to “story time” with a security guard.

-Sonny-
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  #7  
Old April 7th, 2007, 11:57 AM
Maverick Maverick is offline
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Default Index plays

Geoff says index plays alone would give you an edge at this game. But then he won't say what that is.

I have written him about counting tags. With the BJ paying double and the push on 22, I would think the tags would be different. Do you have any thoughts about counting BJ Switch and possible index plays?

This is one of the games at a favorite comp station.

Maverick
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  #8  
Old April 7th, 2007, 01:06 PM
Kasi Kasi is offline
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AM - Would your BS be the same for the Playtech game?

AKA23 - would u have a list of 5 or 10 plays that give different switch decisions than the Wiz website?

Maverick - Do you mean Geoff Hall?
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  #9  
Old April 7th, 2007, 01:54 PM
Maverick Maverick is offline
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Quote:
Originally Posted by Kasi View Post
Maverick - Do you mean Geoff Hall?
Yep.
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  #10  
Old April 7th, 2007, 02:10 PM
Kasi Kasi is offline
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Quote:
Originally Posted by Maverick View Post
Yep.
Thx.

In the game u play (is it in Nevada?) does the dealer check for BJ after you have made your play/switch decision allowing for you to switch to a BJ before he checks?

If not, what would u estimate to be the HA?
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