The I Ching yarrow stalk method, step by step

The yarrow stalk method is the oldest documented way to cast the I Ching: you take fifty stalks, set one aside, and divide and count the remaining forty-nine by fours three times to produce each line. It is slower than tossing three coins — eighteen rounds of counting for a full hexagram — and it gives the four line values with different odds, so yarrow casts produce noticeably more moving yang lines than moving yin lines.

Where the method comes from

The procedure is not in the Zhou text itself. It is sketched in one dense passage of the Great Commentary, the Xici (繫辭), part of the Ten Wings:

大衍之數五十，其用四十有九。分而為二以象兩，掛一以象三，揲之以四以象四時，歸奇於扐以象閏。

"The number of the great expansion is fifty; forty-nine of them are used. Divide them into two to represent the two; hang one to represent the three; count them off by fours to represent the four seasons; return the remainder between the fingers to represent the intercalary month." The same chapter adds that 十有八變而成卦 — "eighteen changes complete a hexagram."

That is all the classic says, and it leaves gaps. The ritual most people follow today is the one Zhu Xi (朱熹) reconstructed in his Zhouyi Benyi (周易本義), in a short appendix on divination procedure (筮儀). Wilhelm's translation describes essentially the same procedure. Earlier and later scholars disagreed about details — for instance whether the "hanging" stalk is taken again in the second and third changes — so treat what follows as the Song-dynasty standard, not the only version that ever existed.

What you need

• Fifty thin sticks of equal length. Dried yarrow (蓍, shi) is traditional; bamboo skewers or any uniform sticks work.
• A clear table, and twenty to forty quiet minutes.
• Paper to record each line as you go, from the bottom up.

One line: the three changes

Before you begin, take one stalk out of the fifty and lay it aside. It is not used again during the whole cast. Commentators from Wang Bi onward read this unused stalk as the Great Ultimate (太極), the one from which the many proceed. You work with forty-nine.

The first change

• Divide. Split the forty-nine stalks into two heaps without counting, left and right. This is "dividing into two."
• Hang one. Take one stalk from the right heap and place it between the little finger and ring finger of your left hand. This is "hanging one."
• Count the left heap by fours. Remove stalks four at a time until one to four are left (if the heap divides evenly, four are left). Place this remainder between the next fingers of the left hand.
• Count the right heap by fours the same way, and place its remainder between the next pair of fingers.

The stalks now in your left hand — the hung one plus the two remainders — will total either 5 or 9. Set them aside. The heap you continue with now holds 44 or 40 stalks.

The second and third changes

Gather the remaining stalks and repeat exactly the same steps: divide, hang one, count both heaps by fours, collect the remainders. This time the stalks in your hand total 4 or 8. Set them aside and repeat once more with what is left; again you remove 4 or 8.

Reading the line

After three changes, the stalks still in play number 36, 32, 28 or 24. Divide by four:

• 36 → 9, old yang: a solid line that will change.
• 32 → 8, young yin: a stable broken line.
• 28 → 7, young yang: a stable solid line.
• 24 → 6, old yin: a broken line that will change.

An equivalent shortcut, used in older manuals, looks at the piles you set aside: a small pile (5 or 4) counts as 3, a large pile (9 or 8) counts as 2, and the three counts add up to the same 6, 7, 8 or 9 — the same arithmetic as the coin method.

Record the line, gather all forty-nine stalks, and begin again for the next line up. Six lines, three changes each: the eighteen changes the Xici mentions. Then read the cast exactly as you would any other — see changing lines for which text to read.

Why the odds differ from coins

In the first change the four left-hand remainders are not equally likely to produce 5 and 9: only one of the four possible remainders on the left (four) yields 9, so on an even split the first pile is small three times in four. In the second and third changes, small and large are even. Multiply these out and you get:

• 6, old yin: 1/16
• 7, young yang: 5/16
• 8, young yin: 7/16
• 9, old yang: 3/16

With three coins the same values come out as 1/8, 3/8, 3/8 and 1/8. Both methods give yin and yang lines in equal measure overall. The difference is in which lines move: with yarrow, a yang line is three times as likely to be moving as a yin line, while with coins both are equally restless. Many readers find that fitting — yang as the active, outgoing force, yin as the receptive one that holds its shape — and some see it as a reason the stalk method is the "truer" oracle. Others answer that the Zhou text never states any odds, and that Zhu Xi himself accepted coin casting as legitimate. The tradition does not settle the question for you.

Two practical effects follow. Yarrow casts have, on average, the same number of moving lines as coin casts (a quarter of all lines), but a hexagram such as Kun with all six lines moving is far rarer by yarrow than by coins. And if you keep a long journal, you will see more transformations from yang to yin than the reverse.

How long it takes, and why that matters

A careful yarrow cast takes most people twenty to forty minutes. That is the method's real argument. The slowness keeps your question in front of you; the repeated dividing and counting quiets the mind in a way a quick coin toss rarely does. The traditional procedure frames it with a moment of stillness, the question spoken or written clearly, and the stalks handled with respect.

The cost is equally real. It is easy to lose count, the steps are fiddly at first, and if you consult often the time adds up. Some readers who want the yarrow odds without the stalks use sixteen tokens in four colours — one, five, seven and three of each — drawing one per line.

When to prefer yarrow over coins

• For a question that matters to you and that you want to hold in mind for a while — a major choice, a turning point, a long-standing difficulty.
• When you want the ritual as much as the answer: the slowness is part of the practice.
• When the yarrow odds matter to your reading, for example if you study how yang and yin lines move.

Coins, or our online caster, are perfectly suited to everyday questions and to anyone still learning the texts. Neither method is more "accurate" in any measurable sense; the question is what helps you ask well and read honestly. See online I Ching vs coins for a wider comparison.

Putting it into practice

If you try yarrow for the first time, rehearse the counting once with no question at stake, so the mechanics do not distract you. Write each line's number down immediately. When the six lines are complete, look the hexagram up in the hexagram library, note which lines are old, and read the primary hexagram, the moving lines and the changed hexagram in that order. Because yarrow gives old yang more often, pay particular attention when an old yin line appears: it is the rarer event, and readers traditionally give it close attention. And whatever method you choose, keep it consistent, so that your record of readings remains comparable over time.