Need help with some SP21 indices

duanedibley

Well-Known Member
#1
So I made a nice little chart with all my Sp21 indices, and then I misplaced my copy of "The Pro's Guide to Spanish 21", and I thought I'd be OK since I had my chart, but now I realize that some of my notation is ambiguous, so I need some help clearing up a few indices.

My game is 8D, S17, LS, No Redoubling. If I remember correctly I just copied the S17 strategy/index charts directly from the book.

Here are the indices I am confused about. I will write what I think they are, so please correct any mistakes you see. To save time I won't mention any hit with N or more cards clauses, since I am not confused about those.

16 vs T: If Surrender is an option: Hit if TC < 2 / otherwise Surrender
If Surrender is not an option: Hit if TC < 3 / otherwise Stand

17 vs A: If Surrender is an option: Surrender if TC > -6 / otherwise Hit
If Surrender is not an option: Hit if TC < -3 / otherwise Stand

A6 vs 4: Double if TC > -5 / otherwise Hit

A7 vs 4: Double if TC > -5 / otherwise Stand

And are there any indices for 88 vs 9/T/A, or do we always split?

Any help would be greatly appreciated!
 

daddybo

Well-Known Member
#2
duanedibley said:
My game is 8D, S17, LS, No Redoubling. If I remember correctly I just copied the S17 strategy/index charts directly from the book.

16 vs T: If Surrender is an option: Hit if TC < 2 / otherwise Surrender
If Surrender is not an option: Hit if TC < 3 / otherwise Stand

17 vs A: If Surrender is an option: Surrender if TC > -6 / otherwise Hit
If Surrender is not an option: Hit if TC < -3 / otherwise Stand

A6 vs 4: Double if TC > -5 / otherwise Hit

A7 vs 4: Double if TC > -5 / otherwise Stand

And are there any indices for 88 vs 9/T/A, or do we always split?

Any help would be greatly appreciated!

Here ya go...

8D, S17, LS, No Redoubling.

16 vs X: Surrender -2 Stand +3
17 vs A: Surrender -6 Hit -3
17 vs A: Forfeit +2
A6 vs 4: Double -5 else Hit
A7 vs 4: Double -5 else Hit to -11
8-8 vs 9 split -11 else hit .. split against all other up cards.
 

duanedibley

Well-Known Member
#4
OK I found a couple more indices I am confused about. I have indices of -3 for 9 vs 6 and 11 vs 9. It seems that this means just hit at -3 or below (Double at -2 or greater). Is this correct?

If so why does basic strategy say to Double in these situations, when we are Hitting at a neutral count of -4?
 

FLASH1296

Well-Known Member
#5
Katarina explains what to do when Basic Strategy conflicts with the indices.
In short, If it is early in the shoe use Basic Strategy.
 

daddybo

Well-Known Member
#8
duanedibley said:
OK I found a couple more indices I am confused about. I have indices of -3 for 9 vs 6 and 11 vs 9. It seems that this means just hit at -3 or below (Double at -2 or greater). Is this correct?

If so why does basic strategy say to Double in these situations, when we are Hitting at a neutral count of -4?

9 vs D6: hit to -3 else double
11 vs D9: hit to -5 else double
You double on the index value or greater ... if it's less you hit it.

Flash said it right. When the index conflicts with Basic Strategy near the top of the shoe... use Basic strategy... deeper in the show use the index. Although I would imagine, it's a close call either way. Basic Strategy is usually calculated for a complete deck. That's why you use indices to find you advantage as the cards are played.

Note: All numbers are from Walker's book APGTSP21
 

FLASH1296

Well-Known Member
#10
I cannot fathom the following, but perhaps as a group we can figure this out.

For a Basic Strategy Surrender decision to be correct the hand must have an equity worse than -.50.

That is precisely the same as saying the hand loses > 75% of the time.

Forfeiting a doubled hand in Spanish21 is the same as Surrender.

Katarina's text holds that a stiff hand against a dealer's 7 up wins > 25% of the time;

yet she advises that the Basic Strategy play is to NOT forfeit that hand.

That seemingly fails the test of the hand having a better equity than -.50%

Can someone help me here and clarify how this could be possible ?
 

daddybo

Well-Known Member
#11
FLASH1296 said:
I cannot fathom the following, but perhaps as a group we can figure this out.

For a Basic Strategy Surrender decision to be correct the hand must have an equity worse than -.50.

That is precisely the same as saying the hand loses > 75% of the time.

Forfeiting a doubled hand in Spanish21 is the same as Surrender.

Katarina's text holds that a stiff hand against a dealer's 7 up wins > 25% of the time;

yet she advises that the Basic Strategy play is to NOT forfeit that hand.

That seemingly fails the test of the hand having a better equity than -.50%

Can someone help me here and clarify how this could be possible ?
Flash... Are we talking about Forfeiting or Surrender? It seems to me it would make a difference. I would argue that "foreiting a doubled hand" is not the same as surrender. at any rate see below.

Walker states "...all hands verses 2-X have EW> -0.5, so it is never profitable for the basic strategy player to surrender against 2-X."

Am I understanding your question?
 

FLASH1296

Well-Known Member
#12

No you are not.

My clumsy verbiage at fault, no doubt.

Basic Strategy is to "forfeit" your doubled hands (same as surrender)
when it becomes a stiff and you are facing a dealer's 8 or >

I hold that I should hoist the white flag if I have a [doubled]
stiff facing a dealer 7, as I cannot take another card.

NOTE: Late Surrender is rare in Spanish21,
with only 17 vs. Ace being a Basic Strategy Surrender.
With Forfeiture, you already know your final holdings.
You cannot hit your doubled hand; ergo your chance of winning is precisely equal to
the dealer's bust percentage. With a stiff hand there are no pushes.
If the dealer's bust percentage is less than 25% you ought to give up your hand.
 

daddybo

Well-Known Member
#13
FLASH1296 said:

No you are not.

My clumsy verbiage at fault, no doubt.

Basic Strategy is to "forfeit" your doubled hands (same as surrender)
when it becomes a stiff and you are facing a dealer's 8 or >

I hold that I should hoist the white flag if I have a [doubled]
stiff facing a dealer 7, as I cannot take another card.

NOTE: Late Surrender is rare in Spanish21,
with only 17 vs. Ace being a Basic Strategy Surrender.
With Forfeiture, you already know your final holdings.
You cannot hit your doubled hand; ergo your chance of winning is precisely equal to
the dealer's bust percentage. With a stiff hand there are no pushes.
If the dealer's bust percentage is less than 25% you ought to give up your hand.

Okay, I'm showing the bust rate for the 7 up card to be 26.6%. But your reasoning seems correct if it is indeed less than 25%.
 

FLASH1296

Well-Known Member
#14
Oh the ignominy !

The shame of it all !

:cool:

You are 100% correct.

Maybe I should delete these stOOpid posts of mine.

Where did I get the notion that the dealer bust % for a 7
was slightly UNDER 25% when it is slightly OVER !

The only good that can come of this embarrassment is that it has
made me think that if the decision is this close why not plug the
True Count into our thinking on Forfeit as we do with Surrender.

The dealer's bust rate does not actually drop at Higher T.C.'s in this
game, but certainly at extreme + or - T.C.'s the decision must be
altered. I think that this is not really a completely trivial matter.

I think this is a good subject for research.
 

daddybo

Well-Known Member
#15
FLASH1296 said:
Oh the ignominy !

The shame of it all !

:cool:

You are 100% correct.

Maybe I should delete these stOOpid posts of mine.

Where did I get the notion that the dealer bust % for a 7
was slightly UNDER 25% when it is slightly OVER !

:laugh: The charts are tooo small for anybody over 40. I had to look twice, because I saw the same thing you did the first time.
FLASH1296 said:
The only good that can come of this embarrassment is that it has
made me think that if the decision is this close why not plug the
True Count into our thinking on Forfeit as we do with Surrender.

The dealer's bust rate does not actually drop at Higher T.C.'s in this
game, but certainly at extreme + or - T.C.'s the decision must be
altered. I think that this is not really a completely trivial matter.

I think this is a good subject for research.
Funny, I was thinking the same thing... but especially the extreme lower TCs. The game looks soo much different than BJ when your playing it that I haven't developed the the sixth sense that I have playing BJ. :)
 
#16
I'll check this out.

There may also be a point to forfeit with a 17 in a high count against 8-10. This would be more valuable because of the amount of money a SP21 player has on the table in a high count.
 

daddybo

Well-Known Member
#17
Automatic Monkey said:
I'll check this out.

There may also be a point to forfeit with a 17 in a high count against 8-10. This would be more valuable because of the amount of money a SP21 player has on the table in a high count.

Good Point AM... I believe you are totally right in thinking there are times it would be beneficial to forfeit the 17 against strong up cards in High + TCs. Just guessing, I would say a forfeit against a 10 at some High count (say +10 or 12) would probably be justified. Let us know what you get. Don't know if it would ever be justified for the 8 or 9 though.
 
#18
And the answer is...

... you never get there! I couldn't synthesize a count low enough where a No-Bust player has an advantage of less than 50% against a dealer 7, using either of the SP21 systems I know. Other systems that use other tags may differ.

So we play this one by the book.

(But I did get a call from a highly skilled AP who watches over ape and man from a distance... thank you R., different count, kind of confirms these results.)
 

daddybo

Well-Known Member
#19
Automatic Monkey said:
... you never get there! I couldn't synthesize a count low enough where a No-Bust player has an advantage of less than 50% against a dealer 7, using either of the SP21 systems I know. Other systems that use other tags may differ.

So we play this one by the book.

(But I did get a call from a highly skilled AP who watches over ape and man from a distance... thank you R., different count, kind of confirms these results.)

Now WE know! Thanks, AM (and R. too)
 
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