I Ching Yarrow Stalks

The I Ching Yarrow Stalk Method is a traditional and ancient technique for generating hexagrams with the I Ching Oracle. It involves using 49 yarrow stalks, which are divided and counted in a specific manner to determine the hexagram lines.

Key Steps:

Fifty yarrow stalks are used, though one stalk is set aside at the beginning and takes no further part in the process of consultation.
The remaining forty-nine stalks are roughly sorted into two piles, and then for the right hand pile one stalk is initially "remaindered"; then the pile is "cast off" in lots of four (i.e., groups of four stalks are removed).
The remainders from each half are combined (traditionally placed between the fingers of one hand during the counting process) and set aside, with the process then repeated twice (i.e., for a total of three times).

The total number of stalks in the remainder pile will necessarily (if the procedure has been followed correctly) be 9 or 5, in the first count, and 8 or 4, in the second and third counts.

9 or 8 is assigned a value of 2; 5 or 4, a value of 3. The total of the three passes will be one of just four values: 6 (2+2+2), 7 (2+2+3), 8 (2+3+3), or 9 (3+3+3). That value is the number of the first line. The forty-nine stalks are then gathered and the entire procedure repeated to generate each of the remaining five lines of the hexagram.

The yarrow-stalk method produces unequal probabilities for obtaining each of the four totals, as shown in the following table. Compared to the three-coin method, the probabilities of the lines produced by the yarrow-stalk method are significantly different.

Probabilities:

Number	Yarrow Stalk probability		Three Coin probability		Yin or Yang	Signifies	Symbol
6	$\frac{1}{16}$	$\frac{8}{16}$	$\frac{2}{16}$	$\frac{8}{16}$	old yin	yin changing into yang	---x---
8	$\frac{7}{16}$	$\frac{8}{16}$	$\frac{6}{16}$	$\frac{8}{16}$	young yin	yin unchanging	--- ---
9	$\frac{3}{16}$	$\frac{8}{16}$	$\frac{2}{16}$	$\frac{8}{16}$	old yang	yang changing into yin	---o---
7	$\frac{5}{16}$	$\frac{8}{16}$	$\frac{6}{16}$	$\frac{8}{16}$	young yang	yang unchanging	-------

Source: Wikipedia