Cun Mouth and Pulse Mouth Are Not the Same Thing: Three Cun, Nine Fields, and Twenty-Seven Hou

Modern readers often treat “Qi Mouth,” “Cun Mouth,” and “Pulse Mouth” as different names for the same place. “Qiheng,” however, deliberately spends space distinguishing them.

The text first says:

The Qi Mouth is the three-Cun region behind the thenar eminence of the hand, the ancestral place where channel qi greatly converges.

It then says:

The pulse of the Cun Mouth lies one Cun and nine fen behind the thenar eminence… the arterial region from one Cun one fen to three Cun where there is swelling and movement is called the pulse of the Pulse Mouth.

Thus, at least within the definitions of this chapter of the Mirror Classic, the three names refer to different ranges.

Qi Mouth: the entire three-Cun field

The Qi Mouth is the largest observational region. The text uses the proportional bone measure from the transverse crease at the thenar eminence to the transverse crease at the elbow to establish three Cun, then arranges Cun, Guan, Chi, and the Twenty-Seven Hou within those three Cun.

Cun Mouth: the more anterior segment where the pulse is readily apparent

The Cun Mouth is described as the one-Cun-nine-fen segment behind the thenar eminence, where the “entrusted harmony of Heavenly truth qi” gathers in a place where it can be more readily seen and felt.

The passage also uses the “terminal boundary of pulse movement” as a reference, showing that localization depends not only on abstract names but also on the actual boundary of palpable pulsation.

Pulse Mouth: the more posterior pulsating range

The source calls the arterial region from one Cun one fen to three Cun behind the thenar eminence the Pulse Mouth and states that the terminal boundary of the Pulse Mouth lies one fen before Guan.

However these ancient divisions are ultimately reconstructed today, one point is clear: the author pays close attention to the spatial boundaries where pulse movement actually appears and disappears.

The Twenty-Seven Hou depend on these boundaries

Without a clear three-Cun coordinate system, Zhou, Cha, Jin, Duan, and the other Hou would remain only names. “Qiheng” divides the whole Qi Mouth “into thirty fen” and places each Hou into a specific field precisely to create a repeatable localization method.

This makes the next question quantifiable: when a pulse wave rises within these fields, by how many fen does it surge, is it broad or sharp, and is it larger anteriorly or posteriorly?

The next article enters the Mirror Classic’s highly distinctive pulse-wave geometry: surging, ridge-rising, and the three-six-nine-fen scale.