Yarrow stalks
The yarrow stalk method of divination was the next major advance in oracle methodology after the turtle shell method. It was comparatively quick and easy to perform. A yarrow stalk is piece of dried stem from the yarrow plant, approximately 15-18 inches in length.
However, the yarrow oracles is not a truly randomized method, since it is statistically biased toward certain answers. It seems fairly clear that the ancient Chinese neither understood nor intended this statistical bias.
The yarrow stalk method is performed as follows:
- use fifty dried stalks of the yarrow plant and a large clear table space
- set aside one stalk to represent unity, using forty-nine stalks for the remainder of the ritual
- for each of the six lines of the hexagram (starting from the bottom and moving up)
- divide and count the stalks three times as follows
- gather the stalks into the left hand
- split them randomly into two bundles with the left thumb
- place the two bundles separately, as left and right piles, onto the table
- take one stalk from the right side pile, hold it between the little finger and ring finger of the left hand
- pick up the left side pile in the left hand
- count the stalks from the pile into separate piles of four, until four or fewer remain
- hold this remainder between the ring and middle finger of the left hand
- pick up the right side pile in the left hand
- count the stalks from the pile into separate piles of four, until four or fewer remain
- hold this remainder between the index and middle finger of the left hand
- set aside all the stalks held between fingers of the left hand
- count the number of piles of four stalks
- if this is not the third iteration, gather all the piles of four together to repeat the dividing and counting process
- after the third iteration, the number of piles of four stalks will be six, seven, eight or nine
- determine the current line of the hexagram from this number: 6 = old yin, 7 = young yang, 8 = young yin, 9 = old yang.
- once six lines have been determined the hexagram is formed
Using this method, the probabilities of each type of line are as follows:
- old yin: 1 in 16 (0.0625)
- young yang: 5 in 16 (0.3125)
- young yin: 7 in 16 (0.4375)
- old yang: 3 in 16 (0.1875)