黄帝问曰∶夫诊脉常以平旦，何也？岐伯对曰∶平旦者，阴气未动，阳气未散，饮食未进，经脉未盛，络脉调均，
（《内
经》作调匀）气血未乱，故乃可诊。过此非也。（《千金》同《素问》《太素》，云∶有过之脉）切脉动静而视精明，察五
色，观五脏有余不足、六腑强弱、形之盛衰。以此参伍，决死生之分。
从鱼际至高骨（其骨自高），却行一寸，其中名曰寸口。从寸至尺，名曰尺泽。故曰尺寸。寸后尺前，名曰关。阳出
阴入，以关为界。阳出三分，阴入三分，故曰三阴三阳。阳生于尺动于寸，阴生于寸动于尺。寸主射上焦，出头及皮毛
竟手。关主射中焦，腹及腰。尺主射下焦，少腹至足。
夫十二经皆有动脉，独取寸口，以决五脏六腑死生吉凶之候者，何谓也？然∶寸口者，脉之大会，手太阴之动脉也。
人一呼脉行三寸，一吸脉行三寸，呼吸定息，脉行六寸。人一日一夜凡一万三千五百息，脉行五十度，周于身。漏水下
百刻，荣卫行阳二十五度，行阴亦二十五度，为一周（ 时也）。
故五十度而复会于手太阴。太阴者，寸口也，即五脏六腑之所终始，故法取于寸口。脉有尺寸，何谓也？然∶尺寸
者，脉之大会要也。从关至尺是尺内，阴之所治也；从关至鱼际是寸口内，阳之所治也。故分寸为尺，分尺为寸。故阴
得尺内一寸，阳得寸内九分。尺寸终始一寸九分，故曰尺寸也。
脉有太过，有不及，有阴阳相乘，有覆有溢，有关有格，何谓也？然∶关之前者，阳之动也，脉当见九分而浮。过
者，法曰太过；减者，法曰不及。遂上鱼为溢，为外关内格，此阴乘之脉也。关之后者，阴之动也，脉当见一寸而沉。
过者，法曰太过；减者，法曰不及。遂入尺为覆，为内关外格，此阳乘之脉，故曰覆溢。是真脏之脉也，人不病自死。
黄帝问道：诊脉通常选择在清晨（平旦），这是为什么呢？岐伯回答说：清晨时分，阴气尚未躁动，阳气尚未耗散，饮食尚未摄入，经脉之气尚未充盛，络脉之气调和均匀，气血运行没有紊乱，因此此时才可以进行诊察。过了这个时间就不符合这一原则了。（《千金方》与《素问》《太素》相同，说：有“过之脉”即超过正常时间的脉象）。切按脉搏的动静，观察眼睛的神采（视精明），审视面部的五色，观察五脏的有余或不足、六腑的强或弱、形体的盛或衰。将这些情况综合参互比较，从而判断生死预后的界限。
从鱼际穴至高骨（指桡骨茎突，此处骨骼自然较高）向后量取一寸的地方，其中称为寸口。从寸口到尺侧，称为尺泽。所以称为尺寸。寸部之后、尺部之前，称为关。阳气出于外，阴气入于内，以关作为分界。阳气出于关外三分，阴气入于关内三分，所以有三阴三阳之分。阳气生于尺部而表现于寸部，阴气生于寸部而表现于尺部。寸部主要反映上焦的情况，包括头部及皮毛直至手部；关部主要反映中焦的情况，包括腹部及腰部；尺部主要反映下焦的情况，包括小腹至足部。
十二经脉都有搏动的动脉，唯独选取寸口脉，来决断五脏六腑生死吉凶的征候，这是什么道理呢？回答是：寸口，是脉气大会合之处，属于手太阴肺经的动脉。人每呼一次，脉气运行三寸；每吸一次，脉气运行三寸；一呼一吸之间（定息），脉气共运行六寸。人在一天一夜中共呼吸一万三千五百次，脉气运行五十周，循环全身。随着铜壶滴漏滴水一百刻的时间流逝，营气（荣卫）在阳分运行二十五周，在阴分也运行二十五周，完成一周天的循环（指一个周期）。所以脉气运行五十周后，重新会合于手太阴肺经。太阴经，就是寸口，也就是五脏六经脉气终结和起始的地方，所以诊断时取法于寸口。脉有寸部和尺部，这是什么意思呢？回答是：尺寸，是脉气大会合的关键所在。从关到尺侧内部，是尺内，由阴气所治理；从关到鱼际内部，是寸口内，由阳气所治理。所以将寸分为尺，将尺分为寸。因此，阴气占据尺内一寸的位置，阳气占据寸内九分的位置。寸和尺从头到尾总共长一寸九分，所以称为尺寸。
脉象有过盛的，也有不足的，还有阴阳相互乘袭的，有覆脉、溢脉，有关格脉，这是什么意思呢？回答是：关之前的部位，是阳气的活动范围，脉象应当显现为九分深且浮取可得。超过这个程度的，依法称为太过；减少这个程度的，依法称为不及。如果脉气上达鱼际，称为溢脉，表现为外关内格，这是阴气乘袭阳位的脉象。关之后的部位，是阴气的活动范围，脉象应当显现为一寸深且沉取可得。超过这个程度的，依法称为太过；减少这个程度的，依法称为不及。如果脉气深入尺部以下，称为覆脉，表现为内关外格，这是阳气乘袭阴位的脉象，所以称为覆溢。这是真脏脉的表现，即使病人没有明显病症，也会死亡。
Yellow Emperor asked, saying: Why is pulse diagnosis usually performed at dawn (Pingdan)? Qibo replied: At dawn, Yin Qi (Yin Energy) has not yet stirred, Yang Qi (Yang Energy) has not yet dispersed, food and drink have not been ingested, the Jing Mai (Meridians) are not yet full, the Luo Mai (Collaterals) are harmonious and even, and the Qi and Blood are not yet chaotic. Therefore, it is then possible to diagnose. This principle does not apply after this time. (The *Qianjin Fang* agrees with the *Suwen* and *Taisu*, stating there are "Guo Zhi Mai" pulses, i.e., pulses exceeding normal timing). One must feel the movement and stillness of the pulse, observe the clarity of the eyes (Shi Jing Ming), examine the five colors of the face, and view the excess or deficiency of the Zang Organs (Solid Organs), the strength or weakness of the Fu Organs (Hollow Organs), and the flourishing or declining state of the body. By cross-referencing these factors, one can determine the division between life and death.
From the Yuji point (Rice3) to the high bone (the radial styloid process, which is naturally prominent), moving backward one cun, the area in the middle is called Cun Kou (Inch Gate). From Cun Kou to Chi Ze, it is called Chi Ze. Hence, it is referred to as Cun and Chi. Behind Cun and before Chi is called Guan (Gate). Yang Qi emerges outward, and Yin Qi enters inward; Guan serves as the boundary. Yang Qi emerges three fen outward from Guan, and Yin Qi enters three fen inward from Guan; thus, there are distinctions among the Three Yin and Three Yang meridians. Yang Qi originates at Chi but manifests at Cun; Yin Qi originates at Cun but manifests at Chi. Cun primarily reflects the Upper Jiao (Upper Burner), extending to the head, skin, hair, and down to the hand. Guan primarily reflects the Middle Jiao (Middle Burner), extending to the abdomen and waist. Chi primarily reflects the Lower Jiao (Lower Burner), extending from the lower abdomen to the feet.
Although all twelve Jing Mai (Meridians) have pulsating arteries, why is only Cun Kou selected to determine the prognostic signs of life, death, good fortune, and misfortune for the Zang and Fu organs? The answer is: Cun Kou is the great assembly of the Mai Qi (Pulse Qi) and is the pulsating artery of the Hand Taiyin Lung Meridian. In one exhalation, the pulse travels three cun; in one inhalation, the pulse travels three cun. During the pause between breaths (Ding Xi), the pulse travels six cun. In a day and night, a person breathes 13,500 times, and the pulse travels fifty cycles, circulating through the entire body. As the water clock drips one hundred ke (time units), Ying Qi (Nutritive Qi) and Wei Qi (Defensive Qi) travel twenty-five cycles in the Yang aspects and twenty-five cycles in the Yin aspects, completing one full circuit (cycle). Thus, after fifty cycles, the pulse returns to meet at the Hand Taiyin Lung Meridian. The Taiyin Meridian is Cun Kou, which is where the Qi of the Zang and Fu organs ends and begins; therefore, the method of diagnosis takes its standard from Cun Kou. What is meant by the presence of Cun and Chi in the pulse? The answer is: Cun and Chi are the key points of the great assembly of pulse Qi. From Guan to the inner Chi region is the Chi Nei, governed by Yin Qi; from Guan to the inner Yuji region is the Cun Kou Nei, governed by Yang Qi. Therefore, Cun is divided into Chi, and Chi is divided into Cun. Consequently, Yin occupies one cun within Chi Nei, and Yang occupies nine fen within Cun Nei. The total length of Cun and Chi from beginning to end is one cun and nine fen; hence, it is called Cun Chi.
There are pulses that are excessive (Tai Guo), deficient (Bu Ji), those where Yin and Yang mutually invade (Cheng), those that are Fu (Overturned), Yi (Overflowing), Guan (Blocked), and Ge (Opposed). What do these mean? The answer is: In the region anterior to Guan is the movement of Yang Qi; the pulse should appear at a depth of nine fen and be superficial (Fu). If it exceeds this degree, it is legally termed Tai Guo (Excessive); if it is less than this degree, it is legally termed Bu Ji (Deficient). If the pulse reaches up to Yuji, it is called Yi Mai (Overflowing Pulse), manifesting as Wai Guan Nei Ge (External Blockage and Internal Opposition), which is a pulse of Yin Qi invading the Yang position. In the region posterior to Guan is the movement of Yin Qi; the pulse should appear at a depth of one cun and be deep (Chen). If it exceeds this degree, it is legally termed Tai Guo; if it is less, it is termed Bu Ji. If the pulse sinks into the Chi region below, it is called Fu Mai (Overturned Pulse), manifesting as Nei Guan Wai Ge (Internal Blockage and External Opposition), which is a pulse of Yang Qi invading the Yin position. Thus, they are called Fu and Yi. These are the Mai of the True Zang Organs (Zhen Zang); even if the patient shows no symptoms of illness, death will occur.