Wong Halves Card Counting System
The Wong Halves system is quite a complicated card counting strategy. First of all, it is a level III (level 3) type of advanced system. Still, the thing that makes this system more complex and different than most other systems is the fact that you need to count number with decimals. Like the name of the system itself, you need to count halves such as 0.5 or 1.5 and this tends to be difficult to do.
The level III factor means you are keeping track of up to three units of numbers on the positive and negative sides of the indices such as (-1.5,-1,-0.5,0,+0.5,+1,+1.5). This is a large distribution to keep track of, especially in a real game when you are trying to implement perfect basic strategy and keep an accurate count. The system was first invented by Stanford Wong and was written about in details in his book "Professional Blackjack" in the 1970s.
First of all, the indices are shown below in the table for the Wong Halves count. The chart shows the count points assigned to each card in the deck. This count works by adding or subtracting these points to your mental count that is summing up in your head as you play.
Note that there is no -1.5 value in the index, so you have to remember that no card has this value. Also, this is a balanced system which means that when you start your Wong count at zero before the deck is dealt, the final count should also be zero when the deck is used up. In a way, this is good for gauging and using a reference to determine if your count was accurate through the entire deck. The disadvantage of a balanced system is you may need to do a small conversion between the running count and the true count to figure out your true edge over the house. This is a simple calculation of dividing the running count by the total number of decks of cards in play.
This system is very strong but very difficult to learn, mostly due to adding and subtracting positive and negative fractions. You could multiply the index by 2 to get an index with whole numbers, which are much easier to keep track of. The correlation for betting is actually 99%, which is nearly perfect. You may be happy to know that there are much simpler level I, II and II count systems besides the Wong Halves that will provide a betting correlation differences of only 0% to 2% with playing efficiencies that can be higher than 10% better. For all practical use, not many people use the Wong Halves since there are easier systems out there that were discovered after 1975 which were just as good but much easier to learn.