Blackjack Understanding Illustrious 18 - Player 9 vs Dealer 2

I'm relatively new in AP and still trying to grasp all the details. For example, in Basic Strategy, whether you should DD with a 9 vs. a Dealer 2 depends on table rules. If you are playing a double deck game, DHS17, DAS allowed, you SHOULD DD on a 9 vs. Dearer 2. In looking at the Illustrious 18 chart, Player 9 vs. a Dealer 2 is a +1, regardless of # of decks. So in this case, is the I18 saying ONLY DD if the TC is +1 or higher? If so, why does BS say DD to begin with?

 

First thing first. If you are a serious card counter, you should have more than 18 deviation indices in your repertoire -- for good camouflage at least. The so-called "Illustrious 18" is dangerous, and may become a set of 18 illustrious tells to the casino that you are a card counter.

If you want to limit your number of deviation indices for easier memory, you might as well stop at the top two (insurance buying and for 16 vs. 10). That way, you can still reap about 40% of the total benefit from play deviations with two indices alone.

Lastly, if you play DD, and and know how to bet correctly according to the true count and Kelly criterion, always double down at 9 vs. 2 -- no matter what the true count is. Reason: At 0 or negative true count, your bet should be at the minimum. You can well afford to throw away that minimum-bet hand for providing some cover to your big bets at high positive true counts.