Magic Numbers in Divination using “Yi-jing”

The introduction of Congenital Ba-gua and Acquired Ba-gua highlights three major aspects of Yi:
1) Yin and Yang, properties of opposite nature.
2) the interaction of Yin and Yang, Heaven and Earth, Mountain and River, etc.
3) The Enhancing and Diminishing Effect of Yin and Yang.

The latter signifies the change of Yin and Yang, i.e., Yang enhances while Yin diminish or vice versa. Obviously, if Yang enhances to the maximum, Yin will certainly diminish to the minimum at the same time, after which, Yang will then start to diminish and Yin will start to enhance. Any stage between maximum and minimum is referred as developing. Weather change in a year is a prefect example to demonstrate the change effect of Yin and Yang.

In order to represent different combinations of Lao, Shao, Yin, and Yang which we discussed during the introduction of the Four Stages (四象), we use the numbers 6, 7, 8, and 9. As a general rule of thumb, odd numbers represent Yang and even numbers represent Yin. We have 6 as Lao Yin, 8 as Shao Yin, 7, as Shao Yang, and 9 as Lao Yang. These numbers are derived by ancient casting of Hexagram using 49 pieces of milfoil stalks. This casting method however will take quite some time to derive a hexagram.

The casting of hexagram was then modified by using 3 rounded coins in order to save time. Assuming tails equal to 3 while heads equal to 2, we will have either:
1) three heads, 2 + 2 + 2 = 6, a Lao Yin;
2) two heads and a tail, 2 + 2 + 3 = 7, a Shao Yang;
3) one head and two tails, 2 + 3 + 3 = 8, a Shao Yin; or
4) three tails, 3 + 3 + 3 = 9, a Lao Yang.

Regardless of casting using 49 milfoil stalks or 3 rounded coins, the purpose of which is to preserve the use of these four numbers. Once the numbers of each lines are defined, then we will know what is the Original Hexagram and what is the Changed Hexagram.

For instance, starting from bottom (the initial line) to top (the uppermost), if the numbers of lines are 7, 8, 8, 6, 7, 8, then we know the fourth line (from the bottom) is changing from Yin and Yang, and hence the Original Hexagram Water-Thunder “Zhun” (水雷屯) and the Changed Hexagram is River-Thunder “Sui” (澤雷隨).