The Yin-Yang and Changing Lines in the Qian Divination Method of the I Ching

The coin method of divination is traditionally attributed to Guiguzi of the Warring States period. It became popular in the Tang dynasty and was further promoted in the Song. This method replaces the classic practice of using fifty yarrow stalks with three matching coins. You toss three identical copper coins to obtain a hexagram for the matter in question. Ideally, use round coins with a square hole: in antiquity, the idea that “heaven is round and earth is square” meant the shapes could symbolize heaven and earth. This method is among the simplest and very effective, though I personally believe the yarrow-stalk method is the most correct. The yarrow method is known for producing major hexagrams and, if you want the most precise result, it is better to use yarrow stalks. For casual purposes, the coin method is sufficient.

By common convention, the side of the coin with characters represents yin, while the blank side represents yang. After six throws, interpret the lines as follows: if all three coins show the blank side, this is “old yang” (9), marked with a circle (○), recorded as an unbroken line “—”; by the principle of changing lines, when an old yang line changes, it becomes broken “- -”. If all three coins show the side with characters, this is “old yin” (6), marked with an “X” (×), recorded as a broken line “- -”; when an old yin line changes, it becomes unbroken “—”. Two coins showing the side with characters and one showing the blank side indicate “young yang” (7), recorded as an unbroken line “—”. Two coins showing the blank side and one showing the side with characters indicate “young yin” (8), recorded as a broken line “- -”.

Knowing how to mark the lines is important, but understanding changing lines is crucial. If you don’t know how to interpret the changes, the divination is meaningless because you won’t know which line text to consult. For reference, I’ve included a method for reading changing lines below. Interpretations vary and there is no single definitive rule; however, I find the following approach reasonable.

Method for Interpreting Hexagrams

• All six lines stable: Interpret using the original hexagram’s text. (When none of the lines change, use the text of the cast hexagram to explain the matter in question. The hexagram texts are well known; refer to the “I Ching” for details.)
• One line changes: Interpret using the text of the changing line. (If only one line changes, use the interpretation for that specific changing line.)
• Two lines change: Use the yin line of the changing lines, as yin represents the future. If both changing lines have the same polarity (both yin or both yang), use the text of the first changing line. (If there are two changing lines, interpret using the yin line; if they are the same, use the first changing line’s text.)
• Three lines change: Interpret using the middle changing line’s text and refer to the original hexagram’s text. (If three lines change, use the middle changing line for interpretation and consult the original hexagram’s text.)
• Four lines change: Interpret using the text of the lower stable line. (If four lines change, interpret using the lower of the two lines that did not change.)
• Five lines change: Interpret using the text of the stable line. (If five lines change, interpret using the one line that did not change.)
• All six lines change: For the hexagrams Qian and Kun, interpret using the texts for Nine and Six, respectively. For other hexagrams, interpret using the text of the transformed hexagram. (If all six lines change: if the cast hexagram is Qian, use the Nine text; if it is Kun, use the Six text; for other hexagrams, use the transformed hexagram’s text.)