True Count
Until now I have been talking exclusively about the running count. However, most indices for making plays and counts to increase one’s bet are based on the true count. When you are just beginning play in a single deck game, the running count and the true count are virtually identical. This is about the only time however. The true count is the running count adjusted for the decks or part of a deck remaining to be played. In other words, it is the count per deck. For example, if the running count is 10 and the number of decks remaining in the shoe is five, the true count is +10 divided by 5, or +2. Another example is with a running count of +10 and only two decks remaining in the shoe, the true count is +10 divided by 2, or +5. As you can see, in both of these examples the running count was the same, yet the true count is much different.
The previous example deals with situations when the number of decks is greater than one. If the number of decks is less than one, you have to convert the running count to a true count by dividing the running count by the fraction of a deck remaining to be played. If the running count is two, and ½ deck remains to be played, divide two by one half to get a true count of four. If you have forgotten how to divide a number by a fraction, it is pretty easy, especially when the numerator is one. Multiply the running count by the inverted fraction of a deck remaining. One half inverted becomes 2/1, or simply two. In the above example, the running count, two, is multiplied by ½ inverted, or 2/1. Two times two equals a true count of four. As you can see, if the numerator is 1, such as ½ or ¼, then you simply multiply the running count by the denominator.
Since a six deck shoe is common, let’s use an example of a six deck shoe where a deck has been played. The running count is plus six, meaning there are six more tens and Aces than small cards. There are 103 Aces and tens, and 97 small cards. Normally there would be 100 Aces and tens and 100 small cards. So the tens and Aces are about 40% of the total number of cards. In this example, the true count is 6/5, or about +1.
Now, in a two deck game, with one deck played and a count of plus six, there would be 23 Aces and Tens, and 17 small cards. The true count is also plus six because the number of decks, the divisor, is one. Needless to say, the difference of six cards makes a more dramatic difference with one deck left versus five decks left. So the closer you are to one deck left to be played, the closer the running count is to the true count.
What you are seeing is the principle of dilution. There may be a large jump in the count of a multi-deck game, but the advantageous cards are diluted among the large number of cards yet to be played. Multi-deck games do not have the big swings in true count that single or even two deck games have.
