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# Thread: Double Down on Soft 12

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Originally Posted by Gronbog
it might be reasonable to run this experiment.

Rather than removing an ace, I think the equivalent adjustment for my software would be to discard and count an ace at the start of each shoe (after the burn card). This would place all instances of A,A vs ? into a context where at least three aces have been observed and counted just they would be when playing A,A after splitting.

Does this sound reasonable?
Originally Posted by Cacarulo
Perfectly reasonable. That is what I suggested in a previous post. I think there's a semantic issue about removing an ace, but it's exactly what you're proposing. That's why we're counting it.
In my program I don't burn any cards although I don't think that affects the results.
I didn't forget about this experiment. It just took some time for me to get to it.

Under the conditions suggested above, for doubling over hitting A,A vs 3 I now get +8 as the index S17 (was +9). This matches Cac's simulation result. However, I'm still getting +8 for H17 where Cac's simulation result is +7.

Some suggestions regarding the H17 difference:

1. Encountering this hand with at least three aces and a 3 removed at +7 and +8 is a rare event occurring only 122,878 and 98,232 times respectively over the course of 100 billion rounds I simulated. As such, the EVs that were computed are separated by only 0.5 standard deviations (the standard deviation of the difference in the EVs) giving a probability of about 30.85% that doubling might be correct at +7.
2. My software never computes indices in isolation. It always includes the effects of other related index plays. It does this automatically and I've never found a practical reason to prevent it. In the case of A,A vs 3 at +8, the only relevant index play which can also be triggered downstream would be 12 vs 3 (stand) at +2 (there are others but their indices are too negative for them to be relevant in this situation). I would be interested to see what index Cac and others get for this situation (A,A vs 3, at least 3 aces removed, H17) when 12 vs 3 is also enabled. This would tend to increase the value of hitting and therefore tend to make the index for doubling higher.

2. Did you find this post helpful? Yes | No
Originally Posted by Gronbog
I didn't forget about this experiment. It just took some time for me to get to it.

Under the conditions suggested above, for doubling over hitting A,A vs 3 I now get +8 as the index S17 (was +9). This matches Cac's simulation result. However, I'm still getting +8 for H17 where Cac's simulation result is +7.

Some suggestions regarding the H17 difference:

1. Encountering this hand with at least three aces and a 3 removed at +7 and +8 is a rare event occurring only 122,878 and 98,232 times respectively over the course of 100 billion rounds I simulated. As such, the EVs that were computed are separated by only 0.5 standard deviations (the standard deviation of the difference in the EVs) giving a probability of about 30.85% that doubling might be correct at +7.
2. My software never computes indices in isolation. It always includes the effects of other related index plays. It does this automatically and I've never found a practical reason to prevent it. In the case of A,A vs 3 at +8, the only relevant index play which can also be triggered downstream would be 12 vs 3 (stand) at +2 (there are others but their indices are too negative for them to be relevant in this situation). I would be interested to see what index Cac and others get for this situation (A,A vs 3, at least 3 aces removed, H17) when 12 vs 3 is also enabled. This would tend to increase the value of hitting and therefore tend to make the index for doubling higher.
In the index obtained by simulation I've also included other related plays like 14v3, 13v3 and 12v3.

For S17: 14v3 = -5, 13v3 = -2 and 12v3 = +2
For H17: 14v3 = -6, 13v3 = -3 and 12v3 = +1

I think the difference we have is in 12v3. Check that index.
Note also that in these indices the difference between S17 and H17 is one less, which is also true in AA(A)v3.

Sincerely,
Cac

3. Did you find this post helpful? Yes | No
Originally Posted by Gronbog
I didn't forget about this experiment. It just took some time for me to get to it.

Under the conditions suggested above, for doubling over hitting A,A vs 3 I now get +8 as the index S17 (was +9). This matches Cac's simulation result. However, I'm still getting +8 for H17 where Cac's simulation result is +7.

Some suggestions regarding the H17 difference:

1. Encountering this hand with at least three aces and a 3 removed at +7 and +8 is a rare event occurring only 122,878 and 98,232 times respectively over the course of 100 billion rounds I simulated. As such, the EVs that were computed are separated by only 0.5 standard deviations (the standard deviation of the difference in the EVs) giving a probability of about 30.85% that doubling might be correct at +7.
2. My software never computes indices in isolation. It always includes the effects of other related index plays. It does this automatically and I've never found a practical reason to prevent it. In the case of A,A vs 3 at +8, the only relevant index play which can also be triggered downstream would be 12 vs 3 (stand) at +2 (there are others but their indices are too negative for them to be relevant in this situation). I would be interested to see what index Cac and others get for this situation (A,A vs 3, at least 3 aces removed, H17) when 12 vs 3 is also enabled. This would tend to increase the value of hitting and therefore tend to make the index for doubling higher.

This is how I might handle additional removals.
Code:
```//    add additional specific removals here to change pRank[]
//    pHand[0] += 1;

subsetList *l = NULL;
long elems;
if (cd)
l = new subsetList (inputCount, decks, pen, rc, pHand);
else { // (if ! cd)
short specificRem[10] = {0};
l = new subsetList (inputCount, decks, pen, rc, specificRem);
}

l->getProbRC(rc, probRC, pRank);
elems = l->elems;
delete l;
l = NULL;

//    delete additional specific removals here
//    pHand[0] -= 1;

if (elems == 0) {
cout << "\nAbove (player hand pen/running count/side count) input is not possible.";
cout << "\nPress any key to continue";
ch = getch();
return;
}```
I guess for a sim you would remove the extra ace following reshuffle of a full shoe, then replace it before reshuffle.

For 6 decks HiLo these are my approximations for around mid-shoe (155 cards.) I just use best strategy.:

S17
AA v 3 (dbl v hit no ace removed)
RC=23 dbl: 13.514%, hit: 13.238% diff: .276%
RC=22 hit: 12.910%, dbl: 13.054% diff: -.144%
interpolate: RC=22.34, TC=7.5

AA v 3 (dbl v hit 1 ace removed)
RC=22 dbl: 13.572%, hit: 13.241% diff: .331%
RC=21 dbl: 12.972%, hit: 13.059% diff: -.087%
interpolate: RC=21.21, TC=7.1

H17
A-A v 3 (dbl v hit no ace removed)
RC=22 dbl: 13.304%, hit: 13.186% diff: .118%
RC=21 dbl: 12.699%, hit: 13.001% diff: -.302%
interpolate: RC=21.72. TC=7.3

A-A v 3 (dbl v hit 1 ace removed)
RC=21 dbl: 13.347%, hit: 13.185% diff: .162%
RC=20 dbl: 12.747%. hit: 13.003% diff: -.256%
interpolate: RC=20.61, TC=6.9

k_c

4. Did you find this post helpful? Yes | No
Originally Posted by Cacarulo
In the index obtained by simulation I've also included other related plays like 14v3, 13v3 and 12v3.

For S17: 14v3 = -5, 13v3 = -2 and 12v3 = +2
For H17: 14v3 = -6, 13v3 = -3 and 12v3 = +1

I think the difference we have is in 12v3. Check that index.
Good call to also check the index numbers above with the extra ace removed. I had not bothered to check but, with the extra ace removed, my sim agrees with all of the indices above. I think that the negative indices are too far removed from A,A vs 3 at +7 and +8 to kick in downstream and have any effect with the 4.5/6 penetration we are using.

Are you saying that your H17 index for A,A vs 3 with the extra ace removed is still +7 even with these indices enabled?

5. Did you find this post helpful? Yes | No
Originally Posted by Gronbog
Good call to also check the index numbers above with the extra ace removed. I had not bothered to check but, with the extra ace removed, my sim agrees with all of the indices above. I think that the negative indices are too far removed from A,A vs 3 at +7 and +8 to kick in downstream and have any effect with the 4.5/6 penetration we are using.

Are you saying that your H17 index for A,A vs 3 with the extra ace removed is still +7 even with these indices enabled?
Yes, the indices of 14v3, 13v3 and 12v3 do not vary with the extra ace removed. Therefore the index of AA(A)v3 still gives me +7.

Sincerely,
Cac

6. Did you find this post helpful? Yes | No
Originally Posted by k_c
For 6 decks HiLo these are my approximations for around mid-shoe (155 cards.) I just use best strategy.:

S17
AA v 3 (dbl v hit no ace removed)
RC=23 dbl: 13.514%, hit: 13.238% diff: .276%
RC=22 hit: 12.910%, dbl: 13.054% diff: -.144%
interpolate: RC=22.34, TC=7.5

AA v 3 (dbl v hit 1 ace removed)
RC=22 dbl: 13.572%, hit: 13.241% diff: .331%
RC=21 dbl: 12.972%, hit: 13.059% diff: -.087%
interpolate: RC=21.21, TC=7.1

H17
A-A v 3 (dbl v hit no ace removed)
RC=22 dbl: 13.304%, hit: 13.186% diff: .118%
RC=21 dbl: 12.699%, hit: 13.001% diff: -.302%
interpolate: RC=21.72. TC=7.3

A-A v 3 (dbl v hit 1 ace removed)
RC=21 dbl: 13.347%, hit: 13.185% diff: .162%
RC=20 dbl: 12.747%. hit: 13.003% diff: -.256%
interpolate: RC=20.61, TC=6.9

k_c
Hi k_c,

Your approximations are very good despite not taking pen into account.
These are my numbers:

Code:
```
S17
AAv3    = +7.4
AA(A)v3 = +7.0

H17
AAv3    = +7.2
AA(A)v3 = +6.8```

Sincerely,
Cac

7. Did you find this post helpful? Yes | No
Originally Posted by Cacarulo
Yes, the indices of 14v3, 13v3 and 12v3 do not vary with the extra ace removed. Therefore the index of AA(A)v3 still gives me +7.
OK, but what I'm trying to clarify is whether the plays associated with those indices were made while calculating the index for A,A(A)v3. In particular, for H17, did the calculation assume standing on 12v3 at TC>=+1 after hitting A,A(A)v3 ?

8. Did you find this post helpful? Yes | No
Originally Posted by Gronbog
OK, but what I'm trying to clarify is whether the plays associated with those indices were made while calculating the index for A,A(A)v3. In particular, for H17, did the calculation assume standing on 12v3 at TC>=+1 after hitting A,A(A)v3 ?
Yes.

Cac

9. Did you find this post helpful? Yes | No
Originally Posted by Cacarulo
Hi k_c,

Your approximations are very good despite not taking pen into account.
These are my numbers:

Code:
```
S17
AAv3    = +7.4
AA(A)v3 = +7.0

H17
AAv3    = +7.2
AA(A)v3 = +6.8```
Sincerely,
Cac

The only simple method I'd have to use TC based on game pen is to use the TC at pen/2. Additionally since I use RC after player hand is dealt but before up card the TC is for pen/2 - 1. I do this because that's how my CA works. So for 6 decks dealt 4.5/6 = 234/312 I might approximate TC at 234/2 - 1 = 116 cards.

I think this might be better for more decks. If I use this method to compute generic insurance assuming deal to last card (HiLo) to get an example for comparison -

single deck, TC=1.39 with 25 cards remaining
8 decks, TC=3.10 with 207 cards remaining

Above insurance TC is computed without specifically removing an ace, then incorporating ace into RC before computing TC.

It may not be perfect but it is relatively simple. I would be worried that if I tried to weight TCs across differing cards remaining I might be in danger of falling off the edge of the earth.

k_c

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Originally Posted by Midwest Player
I was looking at a new online blackjack game, and their basic strategy said to double down on a soft 12 against a 5 or 6. However, it also said to split Aces. I suppose it would be possible to have a soft 12 if you had a lot of Aces in your hand. Anybody ever hear of such a thing?

More than likely, and noting the fact that you mentioned that this was a "new" online site they simply got confused between S12 and S13 esp. since it says to DD against a 5 or 6...

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