罗东逸曰∶经云∶微妙在脉，不可不察。古今察脉之精。莫过《内经》。《内经》之诊法甚详，脉
法甚约。自叔和《脉经》兴，而脉象繁，为二十四，撰出七表八里九道之名，以为诊病莫尽于此。不知名象
愈繁，诊道莫准，将求精而愈失之。盖由不知脉为胃气之本源，其阴阳精要即相为对待，相去悬绝之间，
有甚精之察，而不必多名象之求也。
夫诊脉求病，求其病之表里寒热虚实顺逆而已。《内经》说脉，止于浮、沉、缓、急、大、小、滑、
涩八脉，特于对待、微甚、悬绝，着其相去之二等，而脉之情尽变极，察之极精。及仲景，又兼以阴阳着
脉为十，以浮、数、动、滑、大为阳，沉、涩、弱、弦、微为阴。而察阴阳之法，又莫过于此。于是诊脉之
精，至此大备。
何以言之？人之先天本于阴阳，而阴阳复生于胃气，惟谷神兴而营气足，故脉行焉。中涵先天四时五
脏之正，而养于胃气，以微见其间，是以脉常有神，而可诊以阴阳逆从之法。故阴阳逆顺之法，必首诊其胃
气、五脏、四时。诊胃气者诊其力，诊五脏者诊其神，诊四时者诊其顺。
何谓力？胃之在三阳，搏而勿浮；在三阴，搏而勿沉。其为洪圆有力，阴阳两和，是平胃脉也。四时而
闰以太息，为五至，于何有病？此谓有力。若胃气衰耗，已先见不搏而浮沉矣。何谓神？五脏五神而主五
行，则恒见微弦、微钩、微软、微毛、微石之平衡，所谓脏真也。过则相凌，弱则受克而藏神失，再过则
真脏现矣，此谓有神。何谓顺？五脏以胃气各自主时而奉天令，故春肝、夏心、秋肺、冬肾，如天之
被物，生、长、化、收、藏。以一旺主时，而群脏从焉，毋得以错迕事见者，所谓顺也。反顺则为
逆矣，逆时则逆脏，并逆胃矣；此谓以顺。是三者病本之诊也。
于是审其阴阳，以别柔刚，而知其逆顺之所在。是以别于阳者，知病起时；别于阴者，知死生之期。
此诊之大源，不可不知也。
嗣是乃有相去之三诊，则于其病情而知之。一法为对待，如浮沉对待，缓急、大小、滑涩各对待，皆两
不相侔，判然可识者也。一法为微甚，从对待而推之，或甚浮微浮、甚沉微沉之过不及，以从容而知之也。
一法为悬绝，如太过、三倍、四倍、不及之迥绝、绝无之殊。此为关格、真脏之见脉，可察而辨也。辨其对
待，以察生克；辨其微甚，以察间甚；辨其悬绝，以察生死。而又察仲景之阴阳十脉。合而察之，前
三法为经，后四法为纬。不待多脉之名象。而死生顺逆之机，了若指掌矣。
罗东逸说：医经中讲：“脉诊的精妙之处，不可不仔细考察。”古今以来，在察脉方面达到精微程度的，没有超过《内经》的。《内经》中的诊法非常详尽，但脉法却十分简约。自从王叔和的《脉经》兴起之后，脉象变得繁杂，分为二十四种，并撰写出“七表、八里、九道”的名称，认为诊断疾病的方法都包含在此之中了。却不知道名称和形象越繁杂，诊断的原则就越不准确，本想追求精准反而更加失之千里。这大概是因为不知道脉是胃气的本源，其中的阴阳精要在于相互对待（对应），在相差悬殊之间，只要有极其精细的观察，就不必去追求过多的脉象名称。
大凡诊脉以求病，不过是探求疾病的表里、寒热、虚实、顺逆罢了。《内经》论述脉象，只限于浮、沉、缓、急、大、小、滑、涩这八种脉，特别强调在对待关系、程度轻重（微甚）、以及差异巨大（悬绝）这几个方面，指出它们之间相差的两个等级，从而将脉的情态变化穷尽到极致，观察得极其精细。到了张仲景，又结合阴阳将脉增加到十种，以浮、数、动、滑、大为阳脉，以沉、涩、弱、弦、微为阴脉。而考察阴阳的方法，没有比这更完备的了。于是，诊脉的精妙，至此已经非常完备了。
为什么说这样呢？人的先天之本源于阴阳，而阴阳又产生于胃气，只有水谷之神旺盛，营气充足，脉才能运行。脉中蕴含先天的四时五脏的正气，并由胃气来滋养，因此脉中微微显现出这种生机，所以脉常有神，可以用阴阳逆从的方法来诊断。因此，运用阴阳逆顺的方法，必须首先诊察胃气、五脏和四时。诊察胃气，是诊察其搏动的力量；诊察五脏，是诊察其神气；诊察四时，是诊察其是否顺应时令。
什么是力量？胃气在三阳经，搏动而不浮散；在三阴经，搏动而不沉伏。如果脉象洪大圆润且有力，阴阳调和，这就是平和的胃气脉。四季之中夹杂太息（深呼吸），脉率约为五至，哪里会有病呢？这就叫有力。如果胃气衰败耗损，就会先出现不搏动而浮或沉的现象。什么是神？五脏各有五神并主宰五行，因此脉象恒常呈现微弦、微钩、微软、微毛、微石这五种脉象的平衡状态，这就是所谓的“脏真”。如果某一种太过就会相凌犯，太弱就会受克制而导致藏神丧失，再严重就会出现真脏脉，这就叫有神。什么是顺？五脏凭借胃气各自在主令之时奉承天令，所以春季肝旺、夏季心旺、秋季肺旺、冬季肾旺，就像上天覆盖万物一样，体现生、长、化、收、藏的规律。由一个脏腑当令主事，其他脏腑都顺从它，没有错乱违背的情况出现，这就叫顺。违背顺就是逆，逆时令就是逆五脏，同时也逆了胃气；这就叫以顺（判断病情）。这三者是诊断疾病根本的方法。
在此基础上审察阴阳，以区分刚柔，从而知道顺逆所在。所以，辨别阳分，就知道疾病起始的时间；辨别阴分，就知道死生的期限。这是诊脉的根本源头，不可不了解。
此后才有这三种相差较大的诊法，通过这种方法可以了解病情。第一种方法是“对待”，如浮与沉相对待，缓与急、大与小、滑与涩各相对待，两者都不相同，界限分明，容易识别。第二种方法是“微甚”，从对待关系中推演，或者过于浮而轻微浮、过于沉而轻微沉等过与不及的情况，从容地加以知晓。第三种方法是“悬绝”，如太过、三倍、四倍，以及不及导致的迥然不同、绝无仅有的差异。这是关格证和真脏脉的表现，可以观察并辨别。辨别它们的对待关系，以观察生克；辨别它们的微甚程度，以观察病情的轻重间隔；辨别它们的悬绝程度，以观察生死。然后再结合张仲景的阴阳十脉进行综合观察。前三法为经，后四法为纬。不需要依赖过多的脉象名称，而死生顺逆的关键，就能像指手掌一样清晰明了了。
Luo Dongyi stated: The medical classics say, "The subtlety lies in the pulse; it must not be neglected." Among all ancient and modern methods of pulse diagnosis, none surpasses the *Neijing* (Inner Canon). The diagnostic methods in the *Neijing* are very detailed, yet the pulse methods are concise. Since Wang Shuhe's *Mai Jing* (Pulse Classic) emerged, pulse images became complex, categorized into twenty-four types, with names such as "Seven Superficial," "Eight Interior," and "Nine Dao" established, under the assumption that diagnostic methods for diseases were exhausted therein. However, one fails to realize that the more numerous the names and images, the less accurate the diagnostic principles become; seeking precision leads further away from it. This is likely due to ignorance that the pulse is the source of Stomach Qi (Stomach Energy), and its essential Yin-Yang dynamics lie in mutual correspondence. Between vast differences, there is a need for extremely precise observation, but not necessarily for seeking numerous pulse images.
Generally, diagnosing the pulse to seek disease involves only determining the exterior-interior, cold-heat, deficiency-excess, and favorable-unfavorable nature of the disease. The *Neijing* discusses only eight pulses: Floating (Fu), Deep (Chen), Moderate (Huan), Rapid/Urgent (Ji), Large (Da), Small (Xiao), Slippery (Hua), and Choppy (Se). It specifically emphasizes their mutual correspondence, degrees of intensity (slight vs. severe), and extreme disparities (suspended/absolute difference), indicating two levels of difference between them, thereby exhausting the variations of pulse conditions and achieving extreme precision in observation. Later, Zhang Zhongjing combined Yin and Yang to expand the pulses to ten, classifying Floating, Rapid (Shu), Agitated (Dong), Slippery, and Large as Yang pulses, and Deep, Choppy, Weak (Ruo), Wiry (Xian), and Minute (Wei) as Yin pulses. The method of observing Yin and Yang could not be better than this. Thus, the sophistication of pulse diagnosis reached its peak here.
Why is this so? The human congenital foundation is based on Yin and Yang, which in turn are generated by Stomach Qi. Only when the spirit of grain (digestive energy) is vigorous and Ying Qi (Nutritive Qi) is sufficient can the pulse circulate. The pulse contains the correct Qi of the congenital Four Seasons and Five Zang Organs, nourished by Stomach Qi, subtly manifesting within. Therefore, the pulse always possesses Shen (Spirit/Vitality), allowing diagnosis via methods of Yin-Yang reversal and compliance. Consequently, applying methods of Yin-Yang reversal and compliance requires first examining Stomach Qi, the Five Zang Organs, and the Four Seasons. Examining Stomach Qi involves assessing its force; examining the Five Zang Organs involves assessing their Shen; examining the Four Seasons involves assessing their compliance.
What is meant by force? When Stomach Qi is in the Three Yang channels, the pulse beats without being floating; when in the Three Yin channels, it beats without being deep. If the pulse is full, round, and forceful, with Yin and Yang harmonized, it is a peaceful Stomach pulse. In the four seasons, interspersed with sighs (deep breaths), resulting in five beats per respiration, where would the disease be? This is called having force. If Stomach Qi declines and dissipates, it will first show signs of beating without force, appearing either floating or deep. What is meant by Shen? The Five Zang Organs have five Shens governing the Five Elements, so the pulse constantly shows a balance of slightly Wiry (Xian), slightly Hook-like (Gou), slightly Soft (Ruan), slightly Hairy (Mao), and slightly Stone-like (Shi) qualities. This is called the "True Zang." If excessive, they invade each other; if weak, they are overcome, leading to loss of Zang Shen; if even more severe, the True Zang pulse appears. This is called having Shen. What is meant by compliance? The Five Zang Organs, relying on Stomach Qi, each dominate during their respective seasons and obey heavenly commands. Thus, Liver dominates Spring, Heart Summer, Lung Autumn, and Kidney Winter, similar to Heaven covering all things, embodying Growth, Flourishing, Transformation, Harvest, and Storage. One organ dominates its season while others follow, without disorder or deviation. This is called compliance. Reversing compliance results in reversal (Ni); reversing the season reverses the Zang, and also reverses Stomach Qi. These three constitute the diagnosis of the disease's root.
Thereupon, one examines Yin and Yang to distinguish soft and hard, knowing the location of compliance and reversal. Therefore, distinguishing Yang reveals the onset time of the disease; distinguishing Yin predicts the period of death or life. This is the great source of diagnosis, which must not be unknown.
Subsequently, there are three methods of significant disparity to understand the disease condition. One method is "Correspondence" (Duì Dài), such as Floating corresponding to Deep, Moderate to Urgent, Large to Small, and Slippery to Choppy. Each pair is unequal and clearly distinguishable. Another method is "Slightness vs. Severity" (Wēi Shèn), deduced from correspondence, identifying excesses or deficiencies, such as severely Floating versus slightly Floating, or severely Deep versus slightly Deep, understood through calm observation. A third method is "Suspended/Absolute Difference" (Xuán Jué), such as excessive (threefold, fourfold) or deficient states that are radically different or non-existent. These are the pulses of Guan Ge (Constraint and Gridlock) and True Zang appearances, which can be observed and distinguished. By discerning correspondence, one observes generation and restriction; by discerning slightness and severity, one observes the interval and severity of illness; by discerning suspended differences, one observes life and death. Furthermore, combining these with Zhang Zhongjing’s Ten Yin-Yang Pulses, the first three methods serve as the warp (vertical axis), and the latter four as the weft (horizontal axis). Without needing numerous pulse names, the mechanisms of life/death and compliance/reversal become clear as pointing at one’s palm.