Secondary Count: 

The ability to track a secondary count as well as a main (primary) 
count at the same time or seperately for playing, insurance, 
and/or betting.

Example: Set main card values to Hi-Opt I which has a .88 Bet 
Correlation. Set secondary values to A= -1, 2= +1.  

  MAIN | SEC.
_______|________
A|  0  |  -1  | 
2|  0  |  +1  |
3| +1  |   0  |
4| +1  |   0  |
5| +1  |   0  |
6| +1  |   0  |
7|  0  |   0  |
8|  0  |   0  |
9|  0  |   0  |
X| -1  |   0  |
---------------

Set options to Use Main Count for play, and Use Secondary + Main 
for betting.  Your betting correlation is now .97 (Hi-lo), while 
maintaining Hi-Opt I's high playing efficiency. 

Used in conjunction with Multiple Strategy Tables, you can even use 
the main count for certain playing strategy decisions, and use the 
secondary count for other playing decisions. Many combinations are
available.

The optimal way to use this above example in play, would be to use
the MAIN count for all playing decisions except, doubling on 8,9
and 10 and splitting 10 valued cards, in which you can add the
SECONDARY count for optimal play.

BJVision is also the only simulator that can perform all of the 
above.

The preceding example was taken from the article:
Can Side-Counting Make You a SUPER COUNTER?
by Arnold Snyder.

You can reference it at:
http://www.rge21.com/lib/sdcnt.htm