二难曰∶脉有尺寸，何谓也？
然∶尺寸者，脉之大要会也。
会，聚也。要会者，言切要聚会之处也。人之一身，经络营卫，五脏六腑，莫不由于阴阳，
而或过与不及、于尺寸见焉，故为脉之大要会也。一难言寸口为脉之大会，以肺朝百脉而言也。
此言尺寸为脉之大要会，以阴阳对待而言也。
从关至尺是尺内，阴之所治也；从关至鱼际是寸内，阳之所治也。
关者，尺寸分界之地，《脉诀》所谓高骨为关是也。关下为尺，主肾肝而沉，故属阴。鱼际，
大指本节后内廉大白肉名曰鱼，其赤白肉分界，即鱼际也。关上为寸口，主心肺而浮，故属
阳。治，理也。欲明阴阳为病之治者。须于尺寸候之也。
故分寸为尺，分尺为寸。
寸为阳，尺为阴，阳上而阴下，寸之下尺也，尺之上寸也，关居其中以为限也。言分寸为尺，
分尺为寸者，谓关上分去一寸，则余者为尺，关下分去一尺，则余者为寸，此明尺寸之所以得
名也。
故阴得尺内一寸，阳得寸内九分。
此又于尺寸中分其长短之位，以合阴阳之数，一寸为偶数，九分为奇数也。盖关以下至尺泽，
皆谓之尺，而诊脉则止候关下一寸，关以上至鱼际，皆谓之寸，而诊脉止候关上九分，故曰∶
尺内一寸，寸内九分也。
尺寸终始，一寸九分，故曰尺寸也。
寸为尺之始，尺者寸之终，云尺寸者，以终始对待而言，其实则寸得九分，尺得一寸，皆阴
阳之盈数也。然得一寸不名曰寸，得九分不名曰分者，以其在尺之中，在寸之中也。
Chapter 2 states: There are the Cun (Inch) and Chi (Cubit) positions in pulse diagnosis; what does this mean?
It is answered: The Cun and Chi positions are the major convergence points of the pulse.
"Hui" (convergence) means gathering. "Yao Hui" (major convergence) refers to the critical location where Qi and Blood gather, which is essential for palpation. The meridians, Ying (Nutritive) Qi and Wei (Defensive) Qi, and the Zang-Fu organs of the human body all derive from Yin and Yang. Excess or deficiency in Yin and Yang manifests at the Cun and Chi positions; therefore, they are called the major convergence points of pulse diagnosis. Chapter 1 states that the Cun Kou (Inch Port) is the great assembly of pulses, speaking from the perspective that the Lung governs all meridians. Here, it states that Cun and Chi are the major convergence points, speaking from the perspective of Yin and Yang as opposing forces.
From the Guan (Gate) position down to the Chi position is the "Chi Nei" (Inner Cubit), the domain governed by Yin; from the Guan position up to the Yu Ji (Fish Border) is the "Cun Nei" (Inner Inch), the domain governed by Yang.
The Guan is the boundary between the Cun and Chi positions, as referred to in the Mai Jue (Pulse Rhymes) as the "high bone." Below the Guan is the Chi position, governing the Kidney and Liver, with a deep pulse quality, thus belonging to Yin. Yu Ji refers to the white fleshy prominence on the medial side behind the first metacarpophalangeal joint of the thumb; the boundary between the reddish and whitish flesh is the Yu Ji. Above the Guan is the Cun Kou, governing the Heart and Lung, with a floating pulse quality, thus belonging to Yang. "Zhi" (govern) means to manage or regulate. To understand the treatment of diseases caused by Yin-Yang imbalance, one must inspect the Cun and Chi positions.
Therefore, the Cun is divided to define the Chi, and the Chi is divided to define the Cun.
The Cun position belongs to Yang, and the Chi position belongs to Yin. Yang is superior and Yin is inferior; the Cun is above the Chi, and the Chi is below the Cun, with the Guan situated in the middle as a limit. The phrase "dividing Cun to form Chi, dividing Chi to form Cun" explains the nomenclature: measuring one Cun upward from the Guan defines the remaining portion as Chi (contextually referring to the measurement logic), and measuring one Chi downward from the Guan defines the remaining portion as Cun. This clarifies the origin of the names Cun and Chi.
Thus, Yin occupies one Cun within the Chi position, and Yang occupies nine Fen within the Cun position.
This further divides the length and position within the Cun and Chi to align with the numbers of Yin and Yang. One Cun is an even number (Yin number), and nine Fen is an odd number (Yang number). Generally, from the Guan position down to the Chi Ze acupoint is all called the Chi position, but in pulse diagnosis, only one Cun below the Guan is palpated. From the Guan position up to the Yu Ji is all called the Cun position, but in pulse diagnosis, only nine Fen above the Guan is palpated. Hence, it is said: "One Cun within the Chi, nine Fen within the Cun."
The total length of the Cun and Chi is one Cun and nine Fen, hence the term "Cun Chi."
The Cun is the beginning of the Chi, and the Chi is the end of the Cun. The term "Cun Chi" is used to denote their opposition as end and beginning. In reality, the Cun position measures nine Fen, and the Chi position measures one Cun, both being complete numbers of Yin and Yang. However, obtaining one Cun is not named merely "Cun," and obtaining nine Fen is not named merely "Fen," because they reside within the respective domains of the Chi and Cun positions.