When the Night Arrives the Bright Moon Appears in Heaven; When the Wind Blows, the Sea-Moon Is Born

I ask why the Earlier Heaven Eight Trigrams are ordered as they are. Looking at the square and circular arrangements of the sixty-four hexagrams, Kun likewise comes first: the upper trigrams follow the order of Kun, Gen, Kan, Xun, Zhen, Li, Dui, Qian, while the lower trigrams begin with “the ruler comes forth in Zhen,” proceeding Zhen, Li, Dui, Qian, Xun, Kan, Gen, Kun—and from Xun to Kun they follow this same sequence.

If we divide them by the two solstices, the yang escape goes from Kun to Qian and the yin escape from Qian to Kun; both may be used. Yet Heaven is honored and Earth is lowly, so taking Qian and Kun as the beginning and the end follows the usual convention. Though it follows that convention, there is also principle to it: according to the Earlier Heaven trigram sequence, the eight trigrams reversed form the binary trigram sequence, and its calculation is already implicit. If one seeks from the bottom upward, it will not match Qian and Kun—one must seek from the top to obtain it. Judging by this, its weight is such that the upper is light and the lower is heavy; herein lies the subtlety of reversal.

The geomancy saying about “reversing the parents” likewise truly takes Qian, Kun, Kan, Li, Gen, Dui, Zhen, and Xun as parents, with all the rest as their children. For Qian and Kun, Kan and Li: reversing Qian and Kun still yields Qian and Kun; reversing Kan and Li still yields Kan and Li. Swapping Qian and Kun still gives Qian and Kun, while swapping Kan and Li changes them to Li and Kan—there is but a single shift within the center. Thus its key lies in Kan and Li joining in essence, and the essence of Kan and Li is also the completion of Qian and Kun. Hence the saying: “This pass is no ordinary pass; Qian and Kun join to form it together.” This is the mysterious pass. It is further said: “Kan and Li, water and fire, cross the midheaven; the dragon steps move the emperor’s throne.”

All things that have form and substance must have a stopping point; without a stopping point they cannot take form. Thus yang advances forward while yin goes backward and halts. From Kun to Qian is the birth of the ten thousand things; from Qian to Kun is their completion. Hence Qian begins things and Kun ends them. Looking at Earlier Heaven, Qian is the beginning and Kun precedes—is this not the saying that “the root of death lies in life, and the root of life lies in death”? This is precisely the principle by which the myriad kinds are reckoned from beginning to end.

Thus Qian and Kun are Kan and Li; Kan and Li are Kan and Li. What is called Qian is Kan—essence in one and function in the other; Kun is Li—function in one and essence in the other. The way of essence and function: the essence is Qian and Kun, the function is Kan and Li. Hence things have ebb and growth: water follows the nature of Kan, moistening downward; fire follows the nature of Li, flaming upward. When speaking of water and fire, it is not water and fire; when speaking of below and above, it is not below and above. Therefore it is said: “Heaven’s movement is strong and ever vigorous; Earth’s condition is receptive and yielding.”