
Blackjack Compromise Strategies
What
if I play the strategy for the wrong rules?
Both Basic Strategy and card counting strategies include variations
for the H17 (Hit on 17) and Double after Split (DAS) rules. Some
books do not bother with these variations and provide compromise
tables. So, if you have learned the tables for one set of rules
and play a game with the other rules, what is your loss?
Let's start with Basic Strategy in a sixdeck game. This chart
contains two sets of bars. The set on the left is for the S17 rule.
In Basic Strategy, your edge is negative, so all bars point downwards.
The cyan bar on the left set of bars is the house edge assuming
that the S17 rule exists and you are playing correctly. The dark
blue bar is the edge with the same rule; but this time you are using
the strategy for H17. The small difference is the cost of using
the wrong strategy. The green bar is the edge in an H17 game playing
correctly. The house edge is much worse with H17. The red bar is
also an H17 game, but using the S17 tables. There is a bit of an
additional loss for playing incorrectly. On the right side we see
the same set of bars, except for the DAS rule instead of H17.
The first thing we see from this chart is that playing the right
game is far more important than playing the right strategy. We also
see that the red and green bars are very close on the left and the
blue and cyan bars are very close on the right. This would indicate
that if you wish to learn only one set of tables, you are better
off using the S17 tables than the H17 tables and the nonDAS tables
than the DAS tables. Of course if you run one set of rules 90% of
the time, learn that set.

What
about Card Counting?
Let's try the same experiment with HiLo with the top 20 indexes.
Here cyan is once again an S17 game. But here we display SCOREs
for penetrations from 26 to 130 cards cut off. The thickness of
the cyan area is the loss if we play using the H17 tables. The difference
between the red and green lines is the loss playing an H17 game
with S17 rules. There is barely any loss at all. What we see is
a very small penalty for using incorrect tables. I did not include
the DAS chart as it looks much the same.
Now a full set of indexes will make more of a difference. But few
people use a full set with six decks. And singledeck would make
more of a difference. But singledeck games with S17 or DAS are
difficult to find.


Sim details
 Six decks, S17, DAS, LS 1 player, HiLo, truncate, Sweet 16 &
Fab 4 indexes, halfdeck resolution, 26130 cards penetration
 Six decks, H17, DAS, LS 1 player, HiLo, truncate, Sweet 16 &
Fab 4 indexes, halfdeck resolution, 26130 cards penetration
 Six decks, S17, LS 1 player, HiLo, truncate, Sweet 16 &
Fab 4 indexes, halfdeck resolution, 26130 cards penetration
 Six decks, H17, LS 1 player, HiLo, truncate, Sweet 16 &
Fab 4 indexes, halfdeck resolution, 26130 cards penetration
 Six decks, S17, DAS, LS 1 player, Basic Strategy, 4.5/6 penetration
 Six decks, H17, DAS, LS 1 player, Basic Strategy, 4.5/6 penetration
 Six decks, S17, LS 1 player, Basic Strategy, 4.5/6 penetration
 Six decks, H17, LS 1 player, Basic Strategy, 4.5/6 penetration
 Correct and incorrect strategies
 Optimal betting by full counts in HiLo sims
 Ten billion rounds each


