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Thread: Surrender Question

  1. #27


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    Quote Originally Posted by DSchles View Post
    It means, no, he didn't mean 17 vs. T as a reverse index. 17 vs. A is the reverse index.

    Don
    Well, I think it's the other way around. That's why I asked GB if there wasn't a typo.
    In 17vT, as the TC increases the standing EV decreases, whereas in 17vA, as the TC increases the standing EV also increases. That means 17vT is the reverse.

    Sincerely,
    Cac

  2. #28
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    Quote Originally Posted by k_c View Post
    Yes, there should be a minus sign. Input is 52 cards remaining before up card is dealt and input hand is T-7. After up card 51 cards remain and LS RC index turned out to be -14 for up card of ace and hand of T-7. TC = -14*52/51 = -14.27. In general TC = 52*RC/(cards remaining).

    k_c
    As a counter, we must take into consideration of the dealer’s upcard. This is especially important for DD games. Most professionals here recommend a deviation index of TC=+1 for surrendering the hand 17 vs A; however, you seem to suggest a slightly different index of TC=+0. At the 52-card penetration, if we count the dealer’s upcard A as -1, this will bring your index to even lower TC=-1. Is my understanding correct?

    In practice, I’ll still use RC for this hand decision, and for this hand, I’ll use half the power as insurance needs.

  3. #29


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    Quote Originally Posted by Cacarulo View Post
    Well, I think it's the other way around. That's why I asked GB if there wasn't a typo.
    In 17vT, as the TC increases the standing EV decreases, whereas in 17vA, as the TC increases the standing EV also increases. That means 17vT is the reverse.

    Sincerely,
    Cac
    Nope.
    You use a reverse index for Surrender with 17 vs A if the TC is less than +1. Once you know the dealer doesn't have BJ, you better play it in positive counts (over +1) than Surrendering.
    For 17 vs 10 it's not the same. Only at a certain point (+13) it is correct to Surrender.

    I suspect your thinking is "contaminated" by the European game my friend :-)
    G Man

  4. #30


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    Quote Originally Posted by G Man View Post
    Nope.
    You use a reverse index for Surrender with 17 vs A if the TC is less than +1. Once you know the dealer doesn't have BJ, you better play it in positive counts (over +1) than Surrendering.
    For 17 vs 10 it's not the same. Only at a certain point (+13) it is correct to Surrender.

    I suspect your thinking is "contaminated" by the European game my friend :-)
    I think we use the index in the same way. That's not the point. If we look at the index from the point of view of standing, the reverse index would be 17vT.
    Why do we usually say that an index is reverse? Because as the TC increases the advantage in a certain play decreases. Plays such as 88vT or 88v9 are reverse (for splitting) because as the TC increases the expected value of splitting decreases.
    In the case of surrender the expected value does not change but the expected value of standing does. At least that's how I understand it.

    Sincerely,
    Cac

  5. #31


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    The common knowledge regarding the use of index is what Wong explained in Pro BJ.

    Number: Stand (or double or split) at a count per deck equal to or greater than the number, hit (or do not split) at a count per deck less than the number.
    Surrender number: Surrender if the count per deck equals or exceeds the number, do not surrender if the count per deck is less than the number.


    My understanding of a "reverse index" is when you do apply the decision "the other way". For Surrender, you do not surrender at or above the index (like explained by Wong) but only if the count per deck is less than the index.

    What you're saying is that the basic strategy calls for Standing 17 vs 10 BUT that there's a reverse index at +13, the point where you would not stand anymore but surrender. This is not a reverse index, this is simply the point where the surrender index kicks in. If surrender isn't offer, you would not do anything other than standing.
    G Man

  6. #32


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    Quote Originally Posted by Cacarulo View Post
    At least that's how I understand it.
    And while you're entitled to understand it that way, it isn't the way the rest of us define "reverse index." For all indices, players learn, "If the TC is greater than or equal to the index, insure, surrender, split, double, or stand."
    So, if, all of a sudden, for any given play, we're now making the departure when we're BELOW the index, instead of above it, that is the definition of "reverse index."

    No sense debating this.

    Don

  7. #33
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    Quote Originally Posted by Cacarulo View Post
    I think we use the index in the same way. That's not the point. If we look at the index from the point of view of standing, the reverse index would be 17vT.
    Why do we usually say that an index is reverse? Because as the TC increases the advantage in a certain play decreases. Plays such as 88vT or 88v9 are reverse (for splitting) because as the TC increases the expected value of splitting decreases.
    In the case of surrender the expected value does not change but the expected value of standing does. At least that's how I understand it.


    Sincerely,
    Cac
    Regarding this, Eliot advertised a lot of his split-for-less advantage plays, but I really haven’t got his idea of profiting from these situations.

  8. #34


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    Quote Originally Posted by G Man View Post
    The common knowledge regarding the use of index is what Wong explained in Pro BJ.

    Number: Stand (or double or split) at a count per deck equal to or greater than the number, hit (or do not split) at a count per deck less than the number.
    Surrender number: Surrender if the count per deck equals or exceeds the number, do not surrender if the count per deck is less than the number.


    My understanding of a "reverse index" is when you do apply the decision "the other way". For Surrender, you do not surrender at or above the index (like explained by Wong) but only if the count per deck is less than the index.

    What you're saying is that the basic strategy calls for Standing 17 vs 10 BUT that there's a reverse index at +13, the point where you would not stand anymore but surrender. This is not a reverse index, this is simply the point where the surrender index kicks in. If surrender isn't offer, you would not do anything other than standing.
    You are right, it is clear that my understanding was too far-fetched, being something simpler to see. Thanks for the clarification.

    Sincerely,
    Cac

  9. #35


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    Quote Originally Posted by DSchles View Post
    And while you're entitled to understand it that way, it isn't the way the rest of us define "reverse index." For all indices, players learn, "If the TC is greater than or equal to the index, insure, surrender, split, double, or stand."
    So, if, all of a sudden, for any given play, we're now making the departure when we're BELOW the index, instead of above it, that is the definition of "reverse index."

    No sense debating this.

    Don
    Yes, you're right. I made it more complicated than it was.

    Sincerely,
    Cac

  10. #36


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    Quote Originally Posted by aceside View Post
    As a counter, we must take into consideration of the dealer’s upcard. This is especially important for DD games. Most professionals here recommend a deviation index of TC=+1 for surrendering the hand 17 vs A; however, you seem to suggest a slightly different index of TC=+0. At the 52-card penetration, if we count the dealer’s upcard A as -1, this will bring your index to even lower TC=-1. Is my understanding correct?

    In practice, I’ll still use RC for this hand decision, and for this hand, I’ll use half the power as insurance needs.
    I do take dealer's up card into consideration.

    1. Hand composition is input. (Dealer up card is not considered yet.)
    2. Running count is input.
    3. Number of cards remaining is input. (Dealer up card is still not considered yet.)
    4. A shoe comp is determined based on running count and cards remaining. (Dealer up card is still not considered yet.)
    5. Hand expected values are computed for each up card for this shoe comp. (Dealer up card is now considered in the final count and one fewer cards remain.)
    6. To generate an index, the range of all possible running counts is considered.

    Below shows a calculation for a hand of T-7 with 52 cards remaining before up card is dealt. Running count is -13 before up card is dealt. Running count after up card is dealt depends on its tag. After an up card of ace is dealt running count is -14 and there are 51 cards remaining. Input rules are dealer hits soft 17, NDAS, LS allowed versus A and T, surrender allowed versus 2-9.

    Code:
    Number of decks: 2   Count tags {1,-1,-1,-1,-1,-1,0,0,0,1}
    Player hand composition: 0, 0, 0, 0, 0, 0, 1, 0, 0, 1:  Hard 17, 2 cards
    After player hand is dealt - Cards remaining: 52, Running count: -13
    Subgroup removals: No subgroups are defined
    Shoe comp (A-5):  {2.7996, 5.3296, 5.3296, 5.3296, 5.3296}
    Shoe comp (6-10): {5.3296, 3.5621, 4.071, 4.071, 10.848}
    After up card is dealt - Cards remaining: 51
    Running count (up card 1 to 10): {-14,-12,-12,-12,-12,-12,-13,-13,-13,-14}
    
    Up card   Stand      Hit   Double  Split 1  Split 2  Split 3  Surr     Strat
    
       1    -69.317  -60.990 -100.709                             -60.636   surr
       2    -25.820  -46.127  -92.254                             -50.000  stand
       3    -23.789  -46.206  -92.412                             -50.000  stand
       4    -20.952  -46.625  -93.249                             -50.000  stand
       5    -19.302  -42.725  -85.450                             -50.000  stand
       6    -16.801  -42.999  -85.997                             -50.000  stand
       7    -18.315  -39.144  -78.289                             -50.000  stand
       8    -35.871  -39.634  -79.267                             -50.000  stand
       9    -37.807  -42.983  -85.966                             -50.000  stand
      10    -41.497  -48.363  -91.237                             -52.745  stand
    
    Overall hand EV vs all upcards: -29.8768
    
    Press c or C for EV conditioned on no dealer blackjack, any other key to exit
    To get total dependent indexes the hand composition is not considered, only the up card versus an input total. Total dependent index comes out to RC<1 for 52 cards remaining before up card (LS 17 vs ace).

    That describes my methodology about as simply as I can. It allows for computing all up cards at once.

    k_c
    Last edited by k_c; 05-19-2022 at 07:00 PM.

  11. #37


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    Quote Originally Posted by k_c View Post
    I do take dealer's up card into consideration.

    1. Hand composition is input. (Dealer up card is not considered yet.)
    2. Running count is input.
    3. Number of cards remaining is input. (Dealer up card is still not considered yet.)
    4. A shoe comp is determined based on running count and cards remaining. (Dealer up card is still not considered yet.)
    5. Hand expected values are computed for each up card for this shoe comp. (Dealer up card is now considered in the final count and one fewer cards remain.)
    6. To generate an index, the range of all possible running counts is considered.

    Below shows a calculation for a hand of T-7 with 52 cards remaining before up card is dealt. Running count is -13 before up card is dealt. Running count after up card is dealt depends on its tag. After an up card of ace is dealt running count is -14 and there are 51 cards remaining. Input rules are dealer hits soft 17, NDAS, LS allowed versus A and T, surrender allowed versus 2-9.

    Code:
    Number of decks: 2   Count tags {1,-1,-1,-1,-1,-1,0,0,0,1}
    Player hand composition: 0, 0, 0, 0, 0, 0, 1, 0, 0, 1:  Hard 17, 2 cards
    After player hand is dealt - Cards remaining: 52, Running count: -13
    Subgroup removals: No subgroups are defined
    Shoe comp (A-5):  {2.7996, 5.3296, 5.3296, 5.3296, 5.3296}
    Shoe comp (6-10): {5.3296, 3.5621, 4.071, 4.071, 10.848}
    After up card is dealt - Cards remaining: 51
    Running count (up card 1 to 10): {-14,-12,-12,-12,-12,-12,-13,-13,-13,-14}
    
    Up card   Stand      Hit   Double  Split 1  Split 2  Split 3  Surr     Strat
    
       1    -69.317  -60.990 -100.709                             -60.636   surr
       2    -25.820  -46.127  -92.254                             -50.000  stand
       3    -23.789  -46.206  -92.412                             -50.000  stand
       4    -20.952  -46.625  -93.249                             -50.000  stand
       5    -19.302  -42.725  -85.450                             -50.000  stand
       6    -16.801  -42.999  -85.997                             -50.000  stand
       7    -18.315  -39.144  -78.289                             -50.000  stand
       8    -35.871  -39.634  -79.267                             -50.000  stand
       9    -37.807  -42.983  -85.966                             -50.000  stand
      10    -41.497  -48.363  -91.237                             -52.745  stand
    
    Overall hand EV vs all upcards: -29.8768
    
    Press c or C for EV conditioned on no dealer blackjack, any other key to exit
    To get total dependent indexes the hand composition is not considered, only the up card versus an input total. Total dependent index comes out to RC<1 for 52 cards remaining before up card (LS 17 vs ace).

    That describes my methodology about as simply as I can. It allows for computing all up cards at once.

    k_c
    There are two surrenders on your table that look weird:

    -60.636
    -52.745

    Sincerely,
    Cac

  12. #38


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    Quote Originally Posted by Cacarulo View Post
    There are two surrenders on your table that look weird:

    -60.636
    -52.745

    Sincerely,
    Cac
    Those are unconditional EVs. If I press 'c' to display EV conditioned on no dealer BJ:

    Code:
    Number of decks: 2   Count tags {1,-1,-1,-1,-1,-1,0,0,0,1}
    Player hand composition: 0, 0, 0, 0, 0, 0, 1, 0, 0, 1:  Hard 17, 2 cards
    After player hand is dealt - Cards remaining: 52, Running count: -13
    Subgroup removals: No subgroups are defined
    Shoe comp (A-5):  {2.800, 5.330, 5.330, 5.330, 5.330}
    Shoe comp (6-10): {5.330, 3.562, 4.071, 4.071, 10.848}
    After up card is dealt - Cards remaining: 51
    Running count (up card 1 to 10): {-14,-12,-12,-12,-12,-12,-13,-13,-13,-14}
    
    Up card   Stand      Hit   Double  Split 1  Split 2  Split 3  Surr     Strat
    
       1    -61.027  -50.450 -100.901                             -50.000   surr
       2    -25.820  -46.127  -92.254                             -50.000  stand
       3    -23.789  -46.206  -92.412                             -50.000  stand
       4    -20.952  -46.625  -93.249                             -50.000  stand
       5    -19.302  -42.725  -85.450                             -50.000  stand
       6    -16.801  -42.999  -85.997                             -50.000  stand
       7    -18.315  -39.144  -78.289                             -50.000  stand
       8    -35.871  -39.634  -79.267                             -50.000  stand
       9    -37.807  -42.983  -85.966                             -50.000  stand
      10    -38.099  -45.364  -90.728                             -50.000  stand
    
    Overall hand EV vs all upcards: -29.8768
    
    Press u or U to display unconditional EV, any other key to exit
    Now if I press 'u' EVs revert to previous display.
    Strategies can be obtained from either option.

    k_c

  13. #39


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    Ok.

    Cac

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