Choose a convention before casting
Assign 2 to one side of a coin and 3 to the other. Toss three coins and add their values: the total is 6, 7, 8 or 9. Which side receives which value matters less than keeping the convention consistent.
Repeat six times. The first line belongs at the bottom of the hexagram; later lines are placed above it. Reversing this order changes the hexagram, so label a manual record clearly.
Four numbers, two line shapes
Seven is young yang, a solid line. Eight is young yin, a broken line. Nine is old yang: solid, changing to broken. Six is old yin: broken, changing to solid. Six and nine are changing lines.
Three fair coins have eight equally likely combinations. The probabilities of 6, 7, 8 and 9 are 1/8, 3/8, 3/8 and 1/8. The traditional yarrow procedure has a different changing-line distribution and should not be presented as the same method.
The original and changed hexagrams
Draw the original hexagram from the six line values. Flip only the changing lines to construct the changed hexagram. If none change, the two are identical. This transformation is deterministic and can be checked independently of an AI interpretation.
Wenbu simulates coin outcomes with cryptographic randomness and also accepts physical coin results. The six values, changing positions and King Wen numbers remain visible for review.
A reading does not have to pretend certainty
Traditions differ on how to read multiple changing lines. Wenbu shows every changing position rather than claiming a universal selection rule. The short themes are original reflection prompts, not quotations from a classical edition.
Begin with an open, concrete question. Record what the imagery brings to mind and revisit the note later. What you overlooked and what you actually did can be more useful than repeatedly casting until an answer feels comfortable.
Sources & further reading
Chinese Text Project · Book of Changes ↗Book of Changes · Xi Ci I ↗Traditional interpretations are not established predictions. See the source notes for context.