How to Cast an I Ching Hexagram with Three Coins

The complete three-coin method: how each toss determines a line, why three heads and three tails become changing lines, and the mistakes beginners most often make.

Why three coins

The three-coin method became the standard way to consult the I Ching from the Song dynasty onward. Before that, the orthodox procedure used fifty yarrow stalks, repeatedly divided by hand — a single reading took fifteen minutes or more.

The coin method compresses this to under a minute. The probability distribution differs slightly from the yarrow method, but the structure is identical: six independent draws, each producing one of four possible line types.

Reading each toss

Toss all three coins at once. Each coin reads as:

• Inscribed face (heads) → yang
• Plain face (tails) → yin

Then count how many landed yang and determine the line:

• Three heads → Old Yang — yang at its extreme, a changing line that becomes yin
• Two heads, one tail → Young Yin — a stable yin line
• One head, two tails → Young Yang — a stable yang line
• Three tails → Old Yin — yin at its extreme, a changing line that becomes yang

The counterintuitive part: two heads produce a yin line, and one head produces a yang line. The minority determines the result, because the minority element is where the movement lies.

Building the hexagram

Toss six times. Lines stack from the bottom upward. Your first toss is the bottom line; your sixth toss is the top line.

This direction matters. Hexagram logic grows upward: the lower three lines form the inner trigram (yourself, the internal situation), and the upper three form the outer trigram (external circumstances, other people). Reverse the order and you have a different hexagram entirely.

What changing lines mean

Old Yang and Old Yin are called changing lines. They mark positions that have reached a tipping point and are already transforming.

Flip every changing line to its opposite and you get the derived hexagram, which describes where the situation tends to move. With no changing lines, there is no derived hexagram — you read the primary hexagram alone, and the situation is comparatively stable. This happens roughly one time in six.

Three common mistakes

Re-casting the same question

The traditional guidance is to consult only when you genuinely do not know. Casting repeatedly on one question usually is not a search for an answer — it is waiting for the answer you already wanted. The thing to address at that point is the hesitation itself.

Treating the quality label as a verdict

"Auspicious" and "inauspicious" are not outcomes. The entire orientation of the I Ching is toward navigating conditions well. A difficult hexagram points at where the risk sits; handled properly, it resolves. A favourable one handled carelessly does not stay favourable.

Ignoring the line texts

When changing lines are present, their texts are more specific and more directly relevant than the hexagram judgment. Reading only the hexagram name is like reading only a headline.

Try a cast

Our free online caster implements all of the above: three coins, six tosses, automatic detection of Old Yang and Old Yin, and both primary and derived hexagrams with their line texts. Everything runs locally in your browser — nothing is uploaded.