Da Yan Yarrow Stalk Divination
The yarrow stalk method is the casting procedure the Book of Changes describes for itself, set out in the Great Treatise. It is far more involved than tossing coins, but every step is written down in the text, and it distinguishes old from young lines. This page follows the eighteen changes in order.
Fifty stalks, of which forty-nine are used
The Great Treatise gives the number as fifty, of which forty-nine are used. One stalk is set aside at the outset and takes no part in the procedure. Commentators have long differed over what that one stalk represents, but the operation is not in dispute: it stays out from beginning to end.
Modern practice usually substitutes forty-nine sticks or counting rods for yarrow. The material can change; the number and the dividing steps cannot. It is precisely the distribution of remainders across that count which lets the eighteen changes distinguish old lines from young ones.
Four operations, three changes to a line
One change has four operations. The forty-nine are divided at random into two heaps. One stalk is taken from the right heap and held between the fingers. Each heap is then counted off in fours. The remainders from both heaps are gathered together with the held stalk and set aside.
What remains goes through a second and a third change, and three changes yield one line. The resulting count divided by four can only give six, seven, eight or nine. Six lines are built from the bottom up, eighteen changes in all.
Old and young yin and yang
Six is old yin, seven young yang, eight young yin, nine old yang. The young lines are static. The old ones are the moving lines: having reached their extreme they turn into their opposite, old yang becoming yin and old yin becoming yang.
This is one of the substantive differences from the coin method. Three coins produce old yin and old yang with equal and fairly high frequency, whereas the yarrow procedure does not distribute the four values evenly and yields old lines less often. That the two methods give different distributions of moving lines has been noted and debated for a long time.
Original hexagram, changed hexagram, and which text to read
The eighteen changes give the original hexagram. Turning its old lines into their opposites gives the changed hexagram. If no line is old, there are no moving lines and only the original stands.
Which text to read is decided by how many lines move. The classification set out by Zhu Xi covers seven cases, running from no moving line, where the judgement of the original is read, through one, two, three, four and five moving lines, each with its own rule about whether to read the original or the changed hexagram and which line takes precedence, to all six moving. Other schools order this differently; the rules applied here follow Zhu Xi.
Why anyone still does it the long way
Coins take under a minute; the eighteen changes take a quarter of an hour. Two reasons are usually given for keeping to it. The procedure comes from the canonical text itself, so every step has a documented basis. And the dividing and counting is itself a deliberate rite, which is not the same act as a quick toss.
As far as reading goes, the two are identical once the hexagram exists: six lines, an original and a changed hexagram, and the same rules for which text applies. The difference lies in how the hexagram is arrived at and in the frequency of moving lines.
How to use it
- Begin with forty-nine stalks and complete one change through the four operations
- Three changes make a line; eighteen build the hexagram from the bottom up, each line resolving to six, seven, eight or nine
- Old lines produce the changed hexagram; the number of them decides which text to read