（此二难以下画图，皆下注图也。）
凡此以下画图内。黑白道以分阴阳终始。其天门、地户、人门、鬼门。是阴阳升降关格门户。其气口人迎左右神门。
是呼吸上下尺寸关格门户。（原脱尺字。据李驹纂图句解补。）
阴气始于立秋。阳气始于立冬。
阴气终于立夏。阳气终于立春。
\r天地阴阳升降始终之图\pt40a2.bmp\r
\r手足阴阳流注始终之图\pt40a3.bmp\r
诸阳会于首 诸阴至胸中
\r尺寸阴阳随呼吸出入上下始终图\pt40a4.bmp\r
阴为里随呼至寸内 阳为表随吸至尺外
\r图\pt40a5.bmp\r
此图明其人迎气口左右神门寸尺关前关后一分案素问云人迎气口在颈法象天地要会始终之门户
\r图\pt40a6.bmp\r
三难曰。脉有大过。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。（别本有也
字。以下条考之。当是。）脉当见九分而浮。过者法曰大过。减者法曰不及。遂上鱼为溢。为外关内格。此阴乘之脉也。
吕曰。过者。谓脉过九分出一寸。名曰大过。减者。脉不及九分至八分七分六分也。此为不及之脉也。遂上鱼者。
出一寸至鱼际也。一名溢脉。一名外关之脉。一名内格之脉。一名阴乘之脉。一脉有四名也。丁曰。大过者。寸脉本浮。
又加实大。是为阳大过也。上鱼者。阴阳溢。（按阴字误。当作为。）浮而损小者。是阳不及也。阳不及。则阴出乘之。
又名阴溢。此者是外关内格。虞曰。气有余。脉乃大过。气不足。脉乃不及。外关则内脉不得出。故曰不及。亦曰阴乘
脉。内格则外脉不得入。故曰大过。亦曰溢脉。下文关后之义。反此言之也。
关以后者。阴之动也。脉当见一寸而沉。过者法曰大过。减者法曰不及。遂入尺为覆。为内关外格。此阳乘之脉也。
吕曰。过者。谓脉出过一寸至一分二分三分四分五分。此大过之脉也。减者。谓不满一寸。脉见八分七分或六分五
分。此为不及之脉。遂入尺以言覆。覆脉者。脉从关至尺泽皆见也。此覆行之脉所以言覆者。脉从关至尺泽。脉见一寸。
其余伏行不见也。今从关见至尺泽。故言覆行也。一名覆脉。一名内关。一名外格。一名阳乘之脉也。丁曰。大过者。
为尺脉本沉。又加实大。名曰阴太过。沉之损小者。是谓不及。阴不及则阳入乘之。此为阳覆。又名内关外格也。
故曰覆溢。是其真脏之脉。人不病而死也。
吕曰。脉来见如此者。此皆诸病相乘克之脉。非谓外邪中风伤寒之类。脉已见。人虽未病。病即死。不可治也。丁
曰。此者是自有增损。使阴阳不守本位。有此覆溢。故形不病而死也。虞曰。阴阳不相荣。脉乃上鱼入尺。故曰覆溢之
脉。脉既覆溢。此由关格所致。本经曰。关格者。不得尽其命而死也。不病亦死。
(The illustrations from the Second Difficulty onwards are all annotated below.)
Within the following illustrations, black and white lines distinguish the beginning and end of Yin and Yang. The Heavenly Gate (Tianmen), Earthly Door (Dihu), Human Door (Renmen), and Ghost Gate (Guimen) are the portals of obstruction and rejection (Guan-Ge) for the ascending and descending of Qi. The Qi Kou (Radial Pulse at the wrist), Ying Port (Carotid pulse at the neck), and Shen Men (Spirit Gate) on the left and right are the portals of obstruction and rejection for the upper and lower Cun and Chi positions during respiration. (The character "Chi" is missing in the original text; supplemented according to Li Ju's *Zuantu Jujie*.)
Yin Qi begins at Start of Autumn (Liqiu). Yang Qi begins at Start of Winter (Lidong).
Yin Qi ends at Start of Summer (Lixia). Yang Qi ends at Start of Spring (Lichun).
\rIllustration of the Beginning and End of Ascending and Descending Heaven and Earth Yin and Yang\pt40a2.bmp\r
\rIllustration of the Beginning and End of Flowing and Pouring Hand and Foot Yin and Yang\pt40a3.bmp\r
All Yang meridians converge at the head. All Yin meridians reach the chest.
\rIllustration of the Beginning and End of Upper and Lower Yin and Yang at Cun and Chi Following Respiration In and Out\pt40a4.bmp\r
Yin is interior; with exhalation, it reaches the inner Cun. Yang is exterior; with inhalation, it reaches the outer Chi.
\rIllustration\pt40a5.bmp\r
This illustration clarifies the Ying Port, Qi Kou, left and right Shen Men, Cun, Chi, Guan Qian (before the Guan position), and Guan Hou (after the Guan position). According to the *Su Wen*, the Ying Port and Qi Kou are located at the neck, mirroring Heaven and Earth, serving as the portals to integrate the beginning and end of Yin and Yang.
\rIllustration\pt40a6.bmp\r
The Third Difficulty states: There are pulses that are excessively strong (Da Guo), insufficient (Bu Ji), where Yin and Yang multiply each other (Yin Yang Xiang Cheng), Fu (covering/overlapping), Yi (overflowing), Guan (blocking), and Ge (rejecting). What does this mean? It is answered: Anterior to the Guan position is the movement of Yang. (Other editions have the particle "Ye". Examining subsequent clauses suggests this is correct.) The pulse should appear at nine fen depth and be floating. Exceeding this standard is termed Da Guo. Falling short of this standard is termed Bu Ji. If it extends upward to the Yu Ji (fish belly), it is called Yi (overflowing), Wai Guan Nei Ge (external blocking and internal rejecting), which is a pulse of Yin multiplying (invading).
Lu says: "Excessive" means the pulse exceeds nine fen by one cun, named Da Guo. "Insufficient" means the pulse is less than nine fen, reaching eight, seven, or six fen. This is a pulse of insufficiency. Extending to the Yu Ji means extending one cun to the Yu Ji. It is also called Yi Mai (Overflowing Pulse), Wai Guan Zhi Mai (External Blocking Pulse), Nei Ge Zhi Mai (Internal Rejecting Pulse), and Yin Cheng Zhi Mai (Pulse of Yin Invading). One pulse has four names. Ding says: Da Guo refers to the Cun pulse being originally floating, and additionally becoming solid and large; this is excessive Yang. Extending to the Yu Ji indicates Yin and Yang overflowing. (Note: The character "Yin" is an error and should be interpreted as "acting as".) Floating and diminished/small indicates Yang insufficiency. When Yang is insufficient, Yin comes out to invade it. It is also called Yin Yi. This constitutes external blocking and internal rejecting. Yu says: When Qi is in excess, the pulse becomes excessively strong. When Qi is deficient, the pulse is insufficient. External blocking prevents internal pulse Qi from exiting; thus it is called insufficiency, also Yin invading the pulse. Internal rejecting prevents external pulse Qi from entering; thus it is called excessive strength, also the Overflowing Pulse. The meaning regarding the area posterior to the Guan mentioned later is stated inversely.
Posterior to the Guan position is the movement of Yin. The pulse should appear at one cun depth and be deep. Exceeding this standard is termed Da Guo. Falling short of this standard is termed Bu Ji. If it sinks into the Chi position, it is called Fu (covering), Nei Guan Wai Ge (internal blocking and external rejecting), which is a pulse of Yang multiplying (invading).
Lu says: "Excessive" means the pulse extends beyond one cun by one, two, three, four, or five fen. This is a pulse of excessive strength. "Insufficient" means not reaching one cun; the pulse appears at eight, seven, or six, five fen. This is a pulse of insufficiency. Entering the Chi position describes Fu. A Fu pulse means the pulse is visible from the Guan position to the Chi Ze point. This is why it is called Fu flow: the pulse is visible from Guan to Chi Ze, appearing at one cun. The rest lies hidden and invisible. Now, since it is visible from Guan to Chi Ze, it is called Fu flow. It is also called Fu Mai (Covering Pulse), Nei Guan (Internal Blocking), Wai Ge (External Rejecting), and Yang Cheng Zhi Mai (Pulse of Yang Invading). Ding says: Da Guo refers to the Chi pulse being originally deep, and additionally becoming solid and large, named Yin Tai Guo (Yin Excess). Diminished when pressed deeply indicates insufficiency. When Yin is insufficient, Yang enters to invade it. This is Yang Fu, also called Nei Guan Wai Ge.
Therefore, Fu and Yi constitute the True Viscera Pulse (Zhen Zang Mai). Death occurs even without illness.
Lu says: Pulses presenting in this manner are all pulses of mutual multiplication and overcoming among various diseases, not referring to external pathogens such as wind-stroke or cold damage. Once the pulse presents, death occurs even if the person shows no symptoms; it is incurable. Ding says: This arises from inherent increases and decreases, causing Yin and Yang to abandon their proper positions, resulting in Fu and Yi. Thus, the form does not show illness, yet death occurs. Yu says: When Yin and Yang do not nourish each other, the pulse rises to the Yu Ji and enters the Chi position; thus it is called the Fu and Yi pulse. Since the pulse exhibits Fu and Yi, this is caused by Guan Ge. The Classic states: Those with Guan Ge cannot complete their lifespan and die. Death occurs even without illness.