I Ching Coin and Yarrow Methods: Line Probabilities
Three coins give line probabilities 1/8, 3/8, 3/8 and 1/8 for 6, 7, 8 and 9. The traditional yarrow distribution is 1/16, 5/16, 7/16 and 3/16.
Three equal coins
Each coin contributes 2 or 3. Three coins have eight equally likely side patterns: one sums to 6, three to 7, three to 8 and one to 9. Six throws form a hexagram.
Yarrow stalk procedure
Set one of fifty stalks aside. Split the remaining forty-nine, remove one stalk from one group and count the two groups in fours, retaining the remainders. Repeat the counting process three times to obtain one line value; six line values complete a figure.
Why changing Yin differs
The two procedures have equal total Yin and Yang probabilities, but distribute changing states differently. In the yarrow distribution old Yin occurs one time in sixteen while old Yang occurs three times in sixteen.