← Casting a Gua

You need three coins, a piece of paper, and something to write with. You will toss all three coins together six times. Each toss creates one line of the gua.

Begin low enough on the paper to leave room above your first result. A gua is built from the ground upward, like a building: Line 1 is the bottom line and Line 6 is the top line. After every toss, write down the number you produced and draw its line beside it. Then move upward and cast the next line.

Give the coins values

For a simple convention, count heads as 3 and tails as 2. Toss all three coins together and add them. There are only four possible totals:

If you use traditional-style Chinese cash coins, the two faces may not feel naturally like “heads” and “tails.” That is fine: choose one face to count as 3 and the other as 2, and use the same convention throughout the casting.

Why 6 and 9 are unusual

Three coins contain eight equally likely heads-or-tails combinations. Only one combination produces either extreme, while three combinations produce each middle value:

That is why 7 and 8 are much more common than 6 and 9. The traditional language calls 6 and 9 “old” or extreme yin and yang. An extreme is also a point of reversal: like a pendulum reaching the end of its swing, it is ready to move back toward the other direction. Those extreme lines are therefore the moving lines of the reading.

Record all six lines

Write the number as well as the line. The number remembers whether the line is stable or moving. A finished note might look like this:

Line 6   8   ⚋
Line 5   7   ⚊
Line 4   9   ⚊   moving
Line 3   8   ⚋
Line 2   7   ⚊
Line 1   6   ⚋   moving

Six tosses of three coins combine 18 individual heads-or-tails outcomes into one complete gua reading.

Traditional-style Chinese cash coins, with their round body and square center hole, are inexpensive and widely available if you want a little of the visual flavor of the tradition. They work exactly like any other three coins.

Primary and resulting gua

First, read the six lines exactly as you cast them. A 6 is broken and a 9 is solid in the primary gua; their moving status does not change that first figure.

Then make the resulting gua. Change every 6 from broken to solid and every 9 from solid to broken. Leave every 7 and 8 unchanged. If there are no 6s or 9s, the primary and resulting gua are the same.

Find your gua

Every six-line gua is made from two three-line structures called trigrams. Lines 1, 2, and 3 form the lower trigram. Lines 4, 5, and 6 form the upper trigram. Each trigram is also read from the bottom upward.

Find the trigram made by your bottom three lines and select it as Below in The 64 Gua filters. Select your upper three lines as Above. The list will narrow to the gua you cast.

After reading the primary gua and any moving lines, make the resulting gua by changing the 6s and 9s, split it into lower and upper trigrams again, and use the same filters to find it.