TC Question for Mentor-Fred

Fred -

It is interesting to note that you and Snyder went in opposite directions on TC adjustment for your respective advanced counts. Both of you could have used 1DTC, but he went down to a 1/4DTC with his ZEN and you went up to a 2DTC for Mentor. Both approaches being relatively rare.

I used to think that there was nothing wrong with 1/4DTC, it was even endorsed by GeoC, but Norm's sims changed my mind.

Now I'm forced to tell new ZEN students to NOT use the 1/4DTC advice in Blackbelt.

Tell us what made you use a 2DTC for Mentor. zg

Zen,
Think of how things would break down technically if you trued up to 1/4th DTC using a level one count. If you're supposed to stand with 15 vs. 10 when there are four extra high cards remaining for every 52 cards left, at a 1/4th deck calibration, that index number would be +1.0 true. You'd take Insurance at +.75 true, and you'd double with 9 vs. 7 at +.875 true. A math genius would look at two decks in the discard tray and say something like, "There are 8 quarter decks left and the running count is +7 -- so my true is +.875. That's clearly high enough to take Insurance, and right on the line for doubling 9 vs. 7, but not big enough to stand with 15 vs. 10." No problem! But if you rounded off for practicality sake, all three indices would be +1.

Now, truing up at 2 DTC, that same running count of +7 at the same penetration point would produce a +7 true. Your indices would be +6 for Insurance, +7 for 9 vs. 7 and +8 for 15 vs. 10. It allows you to deal with increments that are just as precise as the math geek, but using all whole numbers. In addition, since most blackjack games are the shoe type, the most critical point by far is near the shuffle. With a 2 DTC, your running count will pretty much equal your true count as you wind down towards the shuffle, requiring little or no TC converting.

I found this to be an effort reducer when I play, and have been using the 2 DTC, in half deck graduations for 25 years. I do not divide, but simply use a battery of multipliers that correspond to the cards in the discard tray. Four decks left is a .5 multiplier. Three decks left is a .66 multiplier. Two and a half decks left is a .8 multiplier, etc. It's just something that works smoothly for me, and is quite accurate.

Yes, I see it as superior to 1/4D and 1/2DTC, even 1DTC, perhaps.

It was contra-logical that bigger deck increments (2DTC) would prove more accurate than smaller 1/4 and 1/2D-based TC, for the non-mathmetician. zg

This subject deserves more traction, since I detect a lot of confusion around 1/4DTC vs 1/2DTC vs 1DTC vs 2DTC. zg

I'll provide some basic discussion anyway. Much of this is repetitive from the "how to learn zen" thread, but this collects it in one post.

1/4-deck true count - This true count is computed by dividing the running count by the number of 1/4 decks remaining in the shoe.
- Alternatively, the 1/4DTC can by computed by dividing the running count by 4 and then dividing the result by the number of full decks remaining. However, one the benefits of using a 1/4DTC is that it forces you to be more accurate in your deck estimation. Estimating only the number of full decks remaining would sacrafice some or all of the accuracy that could be gained by using this method.
- The desirable aspect of the 1/4DTC for level two counts is that the players advantage (true edge or TE) can be computed directly from the TC. The players advantage would be TE=TC-1.
- There are a couple of drawbacks to this method that a user would need to overcome. First, you may be dividing your running count by numbers like 13 quarter decks remaining in a six deck shoe (most people will have accuracy problems with such calculations). Secondly, you'll be using TC fractions in your betting ramp (you'll raise your bet at a 1/4DTC of 0.5 and again at 1.0, and even at 0.75 for a level one count), and most people don't handle fractions well.

1/2-deck true count - This true count is computed by dividing the running count by the number of 1/2 decks remaining in the shoe.
- Alternatively, the 1/2DTC can by computed by dividing the running count by 2 and then dividing the result by the number of full decks remaining.
- The desirable aspect of the 1/2DTC for level two counts is that the true count is approximately equal to the full-deck true count for level one counts.

Full-deck true count - This true count is computed by dividing the running count by the number of full decks remaining in the shoe.
- The desirable aspect of the 1DTC is that no unnecessary calculations are used, and no fractions need to be incorporated into your ramp.

2-deck true count - This true count is computed by dividing the running count by the number of 2 deck packets remaining in the shoe.
- Alternatively, the 2DTC can by computed by multiplying the running count by 2 and then dividing the result by the number of full decks remaining.
- The desirable aspect of the 2DTC for level two counts is that it can lead to more accurate index play.

What they have in common
All of the TC calculations lead you to a true count that you can use for betting purposes. Each of them will only be as accurate as your deck estimation. But, given the same deck estimation skills for each, they are equally powerful.

How they differ
Most people can't accurately estimate the number of 1/4 decks remaining in a shoe game, but the 1/4DTC can force them to try to improve their deck estimation skills. However, the 1/4DTC requires that the user be comfortable with fractions both in the calculation of the TC and in applying the TC to the betting ramp. This alone makes it less than desirable. Most people also related their bet ramp to the TC, so converting to true edge (TE) isn't really a very strong benefit to this method.

The 1/2DTC, when applied to a level two count, doesn't result in the fractions that the 1/4DTC does. Consequently, its not necessarily any more cumbersome than the 1DTC or 2DTC methods.

Index plays
As Mr. Renzey stated above, the 1/4DTC will generally be applied with index numbers that have been rounded to integers. This is equivalent to rounding full-deck indices to the nearest integer divisible by 4. This will give up some accuracy, but for a level two count its really about the same as rounding hi-lo indices to an even integer. This amount of rounding would generally be considered acceptable.

Indices for a level two count used with the 1/2DTC would be similar in value and accuracy to full-deck hi-lo indices rounded to integers. These indices can be easily generated by dividing full deck indices by 2 and rounding to an integer. This is convenient for people who are making the transition from a level one count like hi-lo to a level two count like zen (they don't need to relearn all of the indices from scratch).

Full deck indices for any count are the norm. For a level two count, they should be more accurate than values for a level one count. However, users of both counts will generally round or group indices so that they don't have to remember as many numbers. Rounding full-deck, level two count indices to the nearest even integer would sacrafice the same amount of accuracy as rounding 1/2DTC indices to integers. Consequently, users of the 1/2DTC should not round their indices any further than the nearest integer.

Indices for the 2DTC should not be obtained by multiplying the 1DTC indices by two. They have already been rounded to integers for use with the 1DTC and multiplying them by 2 will not remove than rounding. However, if the indices for the 2DTC are derived specifically for that TC, they will allow for greater accuracy than full-deck indices. For a level two count, the 2DTC indices could be rounded to the nearest even integer and still retaind the accuracy of full-deck indices. However, such rounding would defeat the purpose of using the 2DTC in the first place. So, if you're not going to treat each index play as having its own special number, you shouldn't bother with the 2DTC method (unless you're already using the method and don't really want to change).

Summary
If someone is learning their first balanced count, we should recommend using 1DTC unless the indices for the 2DTC are commonly available for their count.

If you're really going to memorize each individual index, without rounding or grouping, the 2DTC can probably gain about as much accuracy (probably a little less) as you would expect to lose by rounding 1DTC indices for a level two count to the nearest even integer. However, you may have to generate your own indices for this TC.

1/2DTC indices for level two counts are as accurate as 1DTC indices rounded to the nearest even integer, and most are equal to indices for level one counts. I personally like to recommend this method to people converting from hi-lo to zen so that they don't have to relearn all of the indices.

Nice Synopsis of TC Variations

I'm learning Mentor and am debating whether to go with
the 2D TC indices, or just divide them in half and use
a 'standard' 1D TC calc. I prefer to divide, unlike Mr. Renzey,
and memorizing multipliers after the BS tables w/ indices seems
so drab.

Are there any serious drawbacks to my proposed conversion
of Mentor indices to a 1D TC basis?

BJinNJ

Follow-up question...

Are the Illustrious 18 the same for every count?
Are they the 18 indices closest to zero? Or, are
they the indices that will profit the most? Or,
some other standard?

I haven't read Don S.'s book yet, but plan to get
BJA3 soon.

BJinNJ

I would suggest you try to use the 2DTC first. It provides an opportunity for an extra sliver of accuracy, and the indices are readily available. If you find it cumbersome in some manner, you can easily move in a direction that you find more efficient.

There are no serious drawbacks to using the 1DTC, its just giving up the opportunity for a very small boost in playing efficiency. Most people give this opportunity up by rounding their indices anyway.

Good luck.

Aloha

Since dividing the Indices in half...

results in a loss of accuracy (understood), is there a
problem with using the 2D TC indices, but calc'ing the
TC using the 1D TC method and multiplying THAT result
by 2, including any fraction?

Mr. Renzey's multipliers seem to be rounded slightly for
ease of use anyway, which is also understandable.
For example, multiplier s/b .667 but used as .7 .

BJinNJ

Your true count, using any method, will only be as accurate as your deck estimation skills allow. Since your choice of 1DTC or 2DTC shouldn't effect your ability to estimate remaining decks, you shouldn't lose any accuracy using the 1DTC and multiplying it by 2 (as long as you don't round before you multiply).

Keep in mind that multiplying by 2 is an extra calculation you need to perform at the table. You need to figure out if you can handle that or not.

Alternatively, you could double the tags for your count. This keeps you from having to multiply by 2, but your RC will be twice as large (doubling level 2 tags will occasionally yield a RC greater than 100). Some people don't handle the large numbers well. You just need to find a practice that you're comfortable with.

Aloha

The Ill. 18 are the indices that provide the greatest value. This includes how often they occur (frequent low index number plays) and how much money you would expect to have on the table at that count (less frequent high index number plays with large bets).

Thanks for the XLNT info/advice!

BJinNJ

If you want to true up to 1 deck with Mentor, then just divide all the published index numbers in half and memorize those. To lose no accuracy at all, divide them completely in half; i.e; stand with 12 vs. 3 at +3.5 T/C rather than at +7, etc.

Thanks Fred...

I was looking at the multipliers again last night and
figure that they come from 2/(# double decks remaining).
That's easy enough, and only the 7 and 3.5 deck values
are rounded a sliver. At less than 2 decks remaining, the
fractions become a bit more challenging, but still OK.

AFA dividing the indices by 2 and truing up to 1 deck,
that's ideal for me. But won't this introduce a sliver
of inaccuracy, as the AlohaPloppy surmised? These
indices don't fall on exactly .25, .5, .75 and integers,
do they? Ergo, they must have some slight rounding,
or truncation, or flooring, for ease of use.

I'm not looking to squeeze out every miniscule fraction
of advantage, at this point. Heck, I'm still working to
get BS down as 'second nature', then I'll work on the
count and indices. Holiday OT at my job will slow me
down for the next 4-6 weeks, but then it's all on me
to be ready to hit the tables in the deep of winter.

Thanks for checking in on us!

BJinNJ

They are NOT. 1/4D and 1/2D TC systems suffer compromised performance due to inaccurate betting.
1D-2D TC schemes are superior for both betting accuracy and ease of use. zg

Can I get an Amen? zg

So with a Balancew Level 2 Zen, count it is recommend to use a 1 DTC conversion instead of 1/2 or 1/4 D TC conversion?

so 1 DTC is like this:

RC at 8, 2 decks left in the shoe then 1 DTC = 4 ?

IS that correct?

Thanks

Preach, it brother!

1DTC or 2DTC systems have smaller denominators for true-count conversion. Hence the results after rounding are both (a) larger, and (b) cover a wider range of integer values after rounding, which allows for finer distinctions as to index numbers and bet ramps.

For example, an index or bet-ramp number might be around 1.3 for a 1/2-DTC system - you'd use an index of 1. Under the same system scaled to 1DTC, you'd use an index of 3 (2.6 rounded up). This is effectively the same thing as using an index of 1.5 with the original 1/2-DTC system, which is closer to the correct 1.3.

Carry this example to a 2DTC equivalent, and the index is 5 (5.2 rounded down). This is even better, because it's equivalent to 5/4 = 1.25 in the original system, which is powerfully close to 1.3

Converting to true count by larger deck chunks allows for finer distinctions using integers to make betting/playing calls. If you're good with fractional indexes and division to non-integer results, then you can do the same thing with a 1/2-DTC or 1/4-DTC system.

Amen!

interesting

I would think not much difference in methods once you employ:
RA indicies which cut the frequency of induce use and any live play betting camo.

Probably best to keep using what one knows or if just starting go with ease of use.

I am considering switching from HiLo to Mentor, although I usually play shoe games, I'd like to have a count that can take advantage of good pitch games if/when I find them. How well does the 2DTC work in a SD game?