Indices please - 8v4, 9v7

[newb99]

Would people let me know their thoughts on the above indices? 8v4 doesn't figure in the I18 and I I've dropped 9v7 into the +5 bit of my spreadsheet - a mistake me thinks.

Many thanks.

Newb99

[Sonny]

Here's what I use:

9 vs. 7= +4
8 vs. 4 = +8

-Sonny-

[sagefr0g]

six deck i double 9v7 at +3.

[newb99]

Cor . . . that was quick!

[kewljason]

Personally I double 9 vs 7 at TC +4. I dropped indices for 8 vs 4 in my first year of counting. It happens so rarely at the correct count that it isnt really worth that much, esp in 6 or 8 deck games, that I play alot. There is good reason why it's not in the top 18 indices! I do play a few more than 18, but that is not one of them. I suppose if you play a good amount of single deck where strategy weighs more heavily, it may be worth learning.

[cardcounter0]

Do yourself a favor, learn 30 risk averse plays and forget the other 120. You'll improve your win rate. The gain from RA indices far exceeds the value of knowing stuff like when hard 7 doubles against the dealer's 3.

8 vs 4 @ +8 ??

A +8 count occurs about once every 200 or so hands. The chances of having two low cards for an 8 and the dealer showing a 4 at that 1 out of 200 +8 count??? I would think if you played 8 hours a day, 7 days a week, every day for a year, only taking Christmas and 4th of July off, you would make this play 2 or 3 times. I could be off, you might be able to pick up as much as an extra 4 big bets over the next 29,000,400 hands.

[kewljason]

I also sometimes think that because most counts dont count 7's 8's or 9's that the accuracy is somewhat compromised. I use RPC which counts 7's but still 8's and 9's arent accounted for and who's to say (unless you side count as well) that even though the ratio of high cards to low is up, that whats really in abundance in the remaining cards is 7-9's, any combination of which makes this a losing hand. For that reason I tend to be a bit conservative vs 4. I'm sure this is mathematically wrong. Surely this fact was taken into consideration when considering indices, but I guess thats my conservative nature.

[newb99]

Yes, quite understandable. With a dealer 4 at a very high count, the jokers in the shoe will be the 7s which aren't tracked in Hi-lo. On balance of probability, there'll be a sufficient number waiting to pop out to marry up with a probable 10 - leaving the house to clean up on a double max unit bet. I think I shall cast this one into the abyss as recommended.

On a simiar line of thought, would it be prudent to deviate from BS and take a more conservative approach to doubling down against 2,3,4s at higher counts (+5, +6, +7, +8)? Doubling down say a 9v3 is going to carry even a higher risk, bearing in mind the possible conbinations of non counted cards and 10s that could pop out? I think one of those 5 million hand sims needs to be run, where doubling against dealers 2,3,4s is replaced with hitting, to see what the alteration in the EV would be. Anyone up for it? - I don't have the software.

I'm assuming that BS was produced using unadjusted (for the count) mathematical probabilities based on a flat-betting approach. Where play is based on spreading 1-8/16 (with the max bet out at +4) this must have an effect on the level of risk where the BS doubling plays against 2,3,4s are made at high counts? ie the potential cost of losing a double max bet (16/32 units) is greater than the gain of winning the hand on a single unit basis? Am I explaining the dilemma OK?

Newb99

[Canceler]

Originally Posted by newb99

On a simiar line of thought, would it be prudent to deviate from BS and take a more conservative approach to doubling down against 2,3,4s at higher counts (+5, +6, +7, +8)? Doubling down say a 9v3 is going to carry even a higher risk, bearing in mind the possible conbinations of non counted cards and 10s that could pop out?

Okay, here’s a shameless plug for k_c’s program.

Now, k_c’s description of his software is a little dry, shall we say? His talk about “shoe state” makes you want to take a nap. It’s actually much more exciting than that. “Shoe state” means you can remove whatever cards you want from the shoe to create whatever count you’re interested in. Then you can find out the EV for any player hand vs. any dealer upcard.


For example, here’s one answer to your question of doubling 9 vs. 3 at a high count (+8). It shows that doubling is still a much better choice than hitting.

[cardcounter0]

Before people start getting off track about uncounted cards, The book "Theory of Blackjack" by Peter Griffin (UCLA math professor and the math authority on blackjack) explains the mathematical proof behind cards that are not counted.

Uncounted cards remain normally distributed, no matter what the "count" is.

In a 6 deck shoe, there are 6 x 4 = 24 8s at the top of shoe. Suppose 3 decks are dealt out. Without counting anything, it is safe to assume there are 12 8s left in the half shoe. HiLo counts the 8 as 0, so it is essentially uncounted.

If the HiLo count was a really high +9? It is most likely there are 12 8s left. If the HiLo count was a really low -9? Most likely still 12 8s left.
The "density" of uncounted cards remains normal.

Also note if you are using KO, where the 7 has 1/2 the value of the other positive cards, in a high negative count KO is only half as effective in predicting a 7 as another low card. So in the classic 14 vs T situation, where 7 is the key card, HiLo is completely worthless for a index, and KO isn't much better.