How is an I Ching reading cast?

Three coins are thrown six times. Each throw gives 6, 7, 8 or 9 — the sixes and nines are "old" lines that change into their opposite, producing a second hexagram. The answer lies in the move between the two.

Why do most sites only show one hexagram?

Because they pick one of 64 at random instead of throwing lines. That loses the changing lines entirely, and with them half of what the method does.

How likely are changing lines?

A nine or a six comes up one throw in eight, so most readings have one or two changing lines. Eighteen per cent have none at all, and five or more is rare enough that you may never see it.

Does the reading change if I reload?

No. The throw is fixed by the link, so the same URL always shows the same lines.

Cast the I Ching Online — Three Coins, Changing Lines, Free

Cast the I Ching

A real throw, not a random pick from 64. Three coins are thrown six times, and each throw gives 6, 7, 8 or 9 — sixes and nines are old lines that turn into their opposite and build a second hexagram. The answer is the move between the two, which is exactly what sites that hand you one random hexagram leave out.

A nine comes up one throw in eight

12.5% each for old yang and old yin — the changing lines. Three coins can only land four ways, and two of them are rare.

37.5% each for the young lines, which stay as they are. That is why most readings have one or two changing lines, not five.

18% of throws change nothing at all, and give a single hexagram with no second one to move toward.

These are not opinions about the method, they are what three coins do. Each coin is heads or tails, so a throw sums to 6, 7, 8 or 9 with probabilities 1:3:3:1. A site that hands you one of 64 hexagrams at uniform random is not doing this and cannot produce changing lines at all.

None of it is prediction. It is a randomiser attached to a 2,500-year-old text. What the text is genuinely good at is forcing a question into words specific enough to answer.