The Twelve Sovereign Hexagrams: How the I Ching Maps the Twelve Months
What they are
The twelve sovereign hexagrams are twelve of the sixty-four, arranged in a circle by their number of yang and yin lines and matched to the twelve months of the year. Starting from Fu, with a single yang line at the bottom, yang grows by one line a month until Qian, all yang. Then from Gou, with a single yin line at the bottom, yin grows by one line a month until Kun, all yin, and the circle returns to Fu.
Their Chinese name, xiaoxi, means waning and waxing: yang growing is waxing, yang retreating is waning. They are also called the sovereign hexagrams (bi gua), each being the ruling hexagram of its month. The scheme belongs to the hexagram calendar of the Han-dynasty scholars Meng Xi and Jing Fang.
The twelve hexagrams and the twelve months
| Month | Hexagram | Lines | Solar term |
|---|---|---|---|
| 11th | 24 Fu | one yang below | Winter Solstice |
| 12th | 19 Lin | two yang below | Major Cold |
| 1st | 11 Tai | three yang below, three yin above | Rain Water |
| 2nd | 34 Dazhuang | four yang below | Spring Equinox |
| 3rd | 43 Guai | five yang below, one yin above | Grain Rain |
| 4th | 1 Qian | all six yang | Grain Fills |
| 5th | 44 Gou | one yin below | Summer Solstice |
| 6th | 33 Dun | two yin below | Major Heat |
| 7th | 12 Pi | three yin below, three yang above | End of Heat |
| 8th | 20 Guan | four yin below | Autumn Equinox |
| 9th | 23 Bo | five yin below, one yang above | Frost Falls |
| 10th | 2 Kun | all six yin | Minor Snow |
The months are those of the traditional Chinese calendar, whose first month begins around the Start of Spring; strictly, the hexagram calendar divides its months by the solar terms. The twelve in order: Fu, Lin, Tai, Dazhuang, Guai, Qian, Gou, Dun, Pi, Guan, Bo, Kun.
How to read the circle
In the first six, yang waxes and yin wanes: yang grows up from the bottom line, one line a month, as yin retreats. In the last six it is the other way round. Laid side by side, the twelve figures show yin and yang rising and falling like a tide.
There is a turning point at each end. In the eleventh month, which holds the winter solstice, yin has reached its limit and one yang line returns: that is Fu, Return. In the fifth month, which holds the summer solstice, yang has reached its limit and one yin line appears: that is Gou. The judgment of Fu reads:
Success. Going out and coming in without harm. Friends come, no blame. Turning back along the way, in seven days comes the return. It is favorable to have somewhere to go.
“In seven days comes the return” has long been read in terms of this coming and going of yin and yang.
Tai and Pi, in the middle, mirror each other. Tai, the first month, has heaven below and earth above, and the Tuan commentary says of it that “heaven and earth meet and all things go through”. Pi, the seventh month, has earth below and heaven above: heaven and earth do not meet. The two moments of the year when yin and yang are in balance are one of flow and one of blockage.
Their place in the hexagram calendar
The hexagram calendar assigns sixty hexagrams to the seventy-two five-day pentads of the year (see solar terms and pentads), and the twelve sovereign hexagrams are its framework. In the table of the Tang monk Yixing’s Dayan calendar, the second pentad of each mid-month solar term belongs to a sovereign hexagram: the second pentad of the Winter Solstice, for example, belongs to Fu, and that of the Autumn Equinox to Guan. The other forty-eight hexagrams share the remaining pentads by rank, and Kan, Li, Zhen and Dui govern the twenty-four solar terms with their twenty-four lines.
What they have to do with casting
The sovereign hexagrams record the rise and fall of yin and yang through the year. They mark the season, not fortune. This site reads a cast only from the primary and resulting hexagrams the coins give (see changing lines); which month it is, or which sovereign hexagram rules it, does not change how a cast is read.