十八难秦越人曰∶“手太阴阳明金也，足少阴太阳水也，金生水, 水流下行而不能上，故在下部。足
厥阴少阳木也，生手太阳少阴火，火炎上行而不能下，故为上部，手心主少阳火，生足太阴阳明土，土主
中宫，故在中部也。”滑伯仁注曰∶手太阴阳明金，下生足太阳少阴水，水性下流，故居下部；足少阴太
阳水，生足厥阴少阳木，木生手少阴太阳火及手心主火，火炎上行，是为上部; 火生足太阴阳明土，土居
中部，复生肺金，此五行子母更相生养者也。观十八难所列之图，乃以手厥阴心主火与手少阳三焦火分诊
在下部右尺，图与注自相背戾，后人翕然宗之，不复查考。且经文只云手之太阴阳明，足之太阳少阴，为
上下部，言肺高而肾下，子母相望之意。按《脉经》以心肺合于上焦，脾胃肝胆合于中焦，肾膀胱合于下
焦，两尺分诊两肾，无手厥阴少阳之语。《千金方》诊法与《脉经》同。顾《灵兰秘典篇》曰∶“膻中者
，臣使之官，喜乐出焉。”启玄子注曰∶“膻中在胸中两乳间，为心君播宣教令，气布阴阳，气和志适，则
喜乐由生。”《脉要精微
论》以左寸之外候心，内以候膻中，膻中为十二脏之一，以其无形，与心肺并居胸中，故诊附焉。《本义》
此图，恐未必是伯仁之意，岂有自相矛盾哉？此必后人泥《脉诀》“右肺大肠脾胃命”之说，而以此图牵合
，因土居中部，乃以火居下部，生中土也。独不思手太阳少阴之火，复何所生耶？智者自能辩之。
按何一阳《医学统宗》有云∶《图注难经》，乃四明张世贤袭取纪天锡、袁坤浓、虞庶旧章，断简残文
，浅附已意，欺为新撰，维扬运司梓行，失旨处颇多，然则《难经本义》之图注，实张世贤之集者，后人增
附梓焉，非滑氏之笔明矣。
十八难中，秦越人说：“手太阴肺经和手阳明大肠经属金，足少阴肾经和足太阳膀胱经属水，金生水，水性向下流而不能向上，所以位于下部。足厥阴肝经和足少阳胆经属木，木生手太阳小肠经和手少阴心经之火，火性炎上而不能下行，所以位于上部。手厥阴心包经和手少阳三焦经属火，火生足太阴脾经和足阳明胃经之土，土主宰中宫，所以位于中部。”滑伯仁注释说：手太阴肺经和手阳明大肠经属金，下生子气为足太阳膀胱经和足少阴肾经之水，水性向下流，所以居于下部；足少阴肾经和足太阳膀胱经属水，水生足厥阴肝经和足少阳胆经之木，木生手少阴心经、手太阳小肠经之火以及手厥阴心包经之火，火性炎上，这是上部；火生足太阴脾经和足阳明胃经之土，土居中部，土又复生肺金，这是五行中子母相互更替相生养育的关系。观察十八难所列的图，竟然将手厥阴心包经之火与手少阳三焦经之火分诊于下部右尺脉，图和注自相矛盾，后人一致尊崇这种说法，不再复查考证。而且经文只说手的太阴、阳明，足的太阳、少阴，分为上下部，表达的是肺位高而肾位低，子母相望的意思。按照《脉经》的说法，心肺合于上焦，脾胃肝胆合于中焦，肾与膀胱合于下焦，两尺脉分别诊察两肾，没有提到手厥阴和手少阳的内容。《千金方》的诊法与《脉经》相同。但是《灵兰秘典论》说：“膻中，是臣使之官，喜乐由此产生。”启玄子王冰注释说：“膻中位于胸中两乳之间，作为心君传播教令的场所，气布散阴阳，气和顺志意适，则喜乐自然产生。”《脉要精微论》认为左寸脉之外候为心，内以候察膻中，膻中是十二脏之一，因为它无形，与心肺并居胸中，所以诊法附属于此。《本义》中的这个图，恐怕未必是滑伯仁的本意，怎么会有自相矛盾呢？这一定是后人拘泥于《脉诀》中“右肺大肠脾胃命”的说法，而用这个图来牵强附会，因为土居中部，就以火居下部，来生成中土。只是没想到手太阳小肠经和手少阴心经的火，又再生什么呢？聪明的人自然能辨别。
按照何一阳在《医学统宗》中的说法：《图注难经》，是四明人张世贤窃取纪天锡、袁坤浓、虞庶的旧章，截取断简残文，浅薄地附上自己的意思，欺骗说是新撰写的，由维扬运司刊刻发行，失旨之处很多。那么，《难经本义》的图注，实际上是张世贤的集注，后人增补附会刊刻的，不是滑氏的手笔，这是明确的。
In the Eighteenth Difficulty, Qin Yueren stated: "The Hand Taiyin Lung and Hand Yangming Large Intestine belong to Metal; the Foot Shaoyin Kidney and Foot Taiyang Bladder belong to Water. Metal generates Water. The nature of water is to flow downward and cannot ascend, therefore it is located in the lower part. The Foot Jueyin Liver and Foot Shaoyang Gallbladder belong to Wood. Wood generates the Fire of the Hand Taiyang Small Intestine and Hand Shaoyin Heart. The nature of fire is to flare upward and cannot descend, therefore it is located in the upper part. The Hand Jueyin Pericardium and Hand Shaoyang Sanjiao (Triple Burner) belong to Fire. Fire generates the Earth of the Foot Taiyin Spleen and Foot Yangming Stomach. Earth governs the Central Palace, therefore it is located in the middle part."
Hua Borun annotated: The Hand Taiyin Lung and Hand Yangming Large Intestine belong to Metal, which generates from below the Water of the Foot Taiyang Bladder and Foot Shaoyin Kidney. Since the nature of water flows downward, it resides in the lower part; the Foot Shaoyin Kidney and Foot Taiyang Bladder belong to Water, which generates the Wood of the Foot Jueyin Liver and Foot Shaoyang Gallbladder. Wood generates the Fire of the Hand Shaoyin Heart, Hand Taiyang Small Intestine, and Hand Jueyin Pericardium. Since the nature of fire flares upward, this constitutes the upper part; Fire generates the Earth of the Foot Taiyin Spleen and Foot Yangming Stomach, which resides in the middle part, and Earth subsequently generates Lung Metal. This represents the mutual generation and nourishment between mother and child within the Five Elements (Wu Xing).
Observing the diagram listed in the Eighteenth Difficulty, it places the Fire of the Hand Jueyin Pericardium and the Fire of the Hand Shaoyang Sanjiao at the right Chi pulse position in the lower part. The diagram contradicts its own annotation. Later generations unanimously revered this view without further verification. Moreover, the classic text only mentions the Hand Taiyin and Hand Yangming, and the Foot Taiyang and Foot Shaoyin, dividing them into upper and lower parts, expressing the idea that the Lung is high and the Kidney is low, with mother and child gazing upon each other. According to the *Mai Jing* (Pulse Classic), the Heart and Lung are combined in the Upper Jiao (Upper Burner), the Spleen, Stomach, Liver, and Gallbladder are combined in the Middle Jiao (Middle Burner), and the Kidney and Bladder are combined in the Lower Jiao (Lower Burner). The two Chi pulses separately diagnose the two Kidneys, with no mention of the Hand Jueyin or Hand Shaoyang. The diagnostic methods in the *Qian Jin Fang* (Essential Prescriptions Worth a Thousand Gold) are identical to those in the *Mai Jing*. However, the *Ling Lan Mi Dian Lun* (Treatise on the Secret Canon of Spiritual Orchids) states: "The Danzhong (Chest Center) is the official of the messenger, from whom joy and pleasure arise." Wang Bing (Qi Xuanzi) annotated: "The Danzhong is located between the two breasts in the chest. It serves as the medium for the Ruler Heart to disseminate orders, distributing Qi and balancing Yin and Yang. When Qi is harmonious and will is content, joy arises naturally." The *Mai Yao Jing Wei Lun* (Treatise on the Essentials and Subtleties of Pulse Diagnosis) holds that the exterior aspect of the left Cun pulse corresponds to the Heart, while internally it diagnoses the Danzhong. The Danzhong is one of the Twelve Zang Organs. Because it is formless, it resides in the chest alongside the Heart and Lung, hence its diagnosis is attached here.
It is likely that the diagram in the *Ben Yi* (Original Meaning) was not Hua Borun's true intent, as it contains self-contradictions. This must be due to later generations adhering rigidly to the saying in the *Mai Jue* (Pulse Rhymes): "Right Lung, Large Intestine, Spleen, Stomach, Mingmen," and forcing the diagram to fit. Because Earth resides in the middle part, they placed Fire in the lower part to generate Middle Earth. They failed to consider: what does the Fire of the Hand Taiyang Small Intestine and Hand Shaoyin Heart generate thereafter? The wise can discern this themselves.
According to He Yiyang's *Yi Xue Tong Zong* (Comprehensive Source of Medical Learning): The *Tu Zhu Nan Jing* (Diagram and Annotation of the Classic of Difficult Issues) was plagiarized by Zhang Shixian of Siming from the old chapters of Ji Tianxi, Yuan Kunlong, and Yu Shu. He took fragments and broken texts, superficially added his own opinions, deceived people by claiming it as a new composition, and had it printed by the Transport Commission of Weiyang. There are many errors in meaning. Therefore, the diagrams and annotations in the *Nan Jing Ben Yi* were actually compiled by Zhang Shixian, with later additions and compilations by others. It is clear that this was not the work of Master Hua.