凡观五色之殊。当审四时之变。经曰。春气在经脉。夏气在孙络。长夏气在肌肉。秋气在皮肤。冬气在骨髓。
气之内外。既因乎时。色之浮沉。当因乎气。故可以气之内外。而知其色之浮沉。亦可以色之浮沉。而知其
气之内外。然浮沉若是。而气色何如。盖尝闻之。天有五行。分时化育。以成万物。春肝木旺。其色当青。若甚
而浮清。是谓太过。病在外。微而沉浊。是谓不及。病在内。春以泽为本。春时色青。如以缟裹绀。曰平。青多泽
少曰病。但青无泽如草滋曰死。夏心火旺。其色当赤。若甚而浮清。是谓太过。病在外。微而沉浊。是谓不及。
病在内。夏以泽为本。夏时色赤。如以缟裹朱。曰平。赤多泽少曰病。但赤无泽。如 血曰死。长夏脾土旺。其
色当黄。若甚而浮清。是谓太过。病在外。微而沉浊。是谓不及。病在内。长夏以泽为本。长夏色黄。如以缟裹
栝蒌实。曰平。黄多泽少曰病。但黄无泽如枳实曰死。秋肺金旺。其色当白。若甚而浮清。是谓太过。病在外。
微而沉浊。是谓不及。病在内。秋以泽为本。秋时色白。如以缟裹红。曰平。白多泽少曰病。但白无泽如枯骨
曰死。冬肾水旺。其色当黑。若甚而浮清。是谓太过。病在外。微而沉浊。是谓不及。病在内。冬以泽为本。冬时
色黑。如以缟裹紫。曰平。黑多泽少曰病。但黑无泽如煤 曰死。凡此四时之色。得其平则不病。不得其平
则病者。亦犹脉之太过实强。病生于外。不及虚微。病生于内也。然当其时而见其色者。常也。非其时而见
其色者。变也。变或先时而见。后时而退者。为太过。后时而见。先时而退者。为不及。太过则薄所胜而乘所
不胜。其不及则所胜妄行。而所生受病。所不胜薄之也。以生克言之。色生时者为虚邪。时生色者为实邪。
色克时者为贼邪。时克色者为微邪。色时相应者为正邪。五色之见。可比例而推也。时日支干。孤虚旺相。
亦可按法而究焉。第病症有三因。气色有十法。又当参伍以通其变矣。若夫非其时而有其气。如冬应寒
而反温。夏应热而反凉。或时已至而气未至。或气已至而时未至。或至而太过。或至而不及。气色与之相
应者。顺时者也。不相应者。逆时者也。此又四时五色之变。其太过不及。可候气而参观也。夫邪气之客于
身也。以胜相加。至其所生而愈。至其所不胜而甚。至于所生而持。自得其位而起。必先定五脏之色脉。乃
可言间甚之时。死生之期也。此皆四时之要也。
凡是观察五色的差异，应当审察四时的变化。医经说：春气在经脉，夏气在孙络（细小的分支络脉），长夏（夏季最后十八天或夏秋之交）气在肌肉，秋气在皮肤，冬气在骨髓。
气的内外分布，既然随着季节而变化，面色的浮沉（浅深），也应当随着气的状态而改变。因此，可以根据气的内外分布来推断面色的浮沉，也可以根据面色的浮沉来推断气的内外分布。然而，面色有浮沉之分，那么气色究竟如何呢？我曾听闻：天有五行，分主四季化育万物，以成就万物。春季肝木旺盛，其面色应当为青色。如果颜色特别明显且浮清，这叫做“太过”，病位在外；如果颜色微弱且沉浊，这叫做“不及”，病位在内。春季以润泽为本底。春季时面色青，如同白绢包裹着青赤色（缟裹绀），称为平人（健康）。青色多而润泽少，称为有病。只有青色而无润泽，像枯草一样，称为死证。
夏季心火旺盛，其面色应当为红色。如果颜色特别明显且浮清，这叫做“太过”，病位在外；如果颜色微弱且沉浊，这叫做“不及”，病位在内。夏季以润泽为本底。夏季时面色红，如同白绢包裹着朱砂色（缟裹朱），称为平人。红色多而润泽少，称为有病。只有红色而无润泽，像凝血一样，称为死证。
长夏脾土旺盛，其面色应当为黄色。如果颜色特别明显且浮清，这叫做“太过”，病位在外；如果颜色微弱且沉浊，这叫做“不及”，病位在内。长夏以润泽为本底。长夏时面色黄，如同白绢包裹着栝蒌实（瓜蒌果实）的颜色（缟裹栝蒌实），称为平人。黄色多而润泽少，称为有病。只有黄色而无润泽，像枳实（干燥的枳壳果实）一样，称为死证。
秋季肺金旺盛，其面色应当为白色。如果颜色特别明显且浮清，这叫做“太过”，病位在外；如果颜色微弱且沉浊，这叫做“不及”，病位在内。秋季以润泽为本底。秋季时面色白，如同白绢包裹着红色（缟裹红），称为平人。白色多而润泽少，称为有病。只有白色而无润泽，像枯骨一样，称为死证。
冬季肾水旺盛，其面色应当为黑色。如果颜色特别明显且浮清，这叫做“太过”，病位在外；如果颜色微弱且沉浊，这叫做“不及”，病位在内。冬季以润泽为本底。冬季时面色黑，如同白绢包裹着紫色（缟裹紫），称为平人。黑色多而润泽少，称为有病。只有黑色而无润泽，像煤炭一样，称为死证。
以上四时的面色，得到平和的状态则不生病，得不到平和状态则生病，这也就像脉象的太过、实强，病生于外；不及、虚微，病生于内一样。然而，在其对应的季节出现相应的面色，是常理；在非对应季节出现相应面色，是变局。变局中，如果在季节未到之前先出现，或在季节过后才消退，属于“太过”；如果在季节过后才出现，或在季节未到之前已消退，属于“不及”。太过则会克制其所胜（我克者）并乘袭其所不胜（克我者）；不及则其所胜者妄行，而其所生者受病，其所不胜者也会来欺凌它。从五行生克来说，色生时者为虚邪，时生色者为实邪，色克时者为贼邪，时克色者为微邪，色与时相应者为正邪。五色的表现，可以类比推演。日时的干支，孤虚旺相等规律，也可以按照法则去探究。只是病症有三因，气色有十法，又应当综合参伍以通晓其变化。至于非其时而有其气，如冬天应该寒冷却反而温暖，夏天应该炎热却反而凉爽，或者时令已到而气候未到，或气候已到而时令未到，或到来而太过，或到来而不及，气色与之相应的，是顺时应势；不相应的，是逆时应势。这又是四时五色变化的情况，其太过与不及，可以通过候气来参观判断。
邪气侵犯身体，是以五行相胜的关系相加加于身。邪气传到它所生的脏腑则痊愈，传到它所不胜的脏腑则加重，传到它所生的脏腑则持稳，回到自身本位则发作。必须首先确定五脏的面色和脉象，才能谈论疾病间甚（减轻与加重）的时间以及死生的期限。这些都是四时望诊的要领。
Whenever observing the differences in the Five Colors, one must examine the changes of the Four Seasons. The Classics state: In Spring, Qi is in the Meridians (Jingmai); in Summer, Qi is in the Collaterals (Sunluo); in Late Summer, Qi is in the Muscles; in Autumn, Qi is in the Skin; and in Winter, Qi is in the Bone Marrow.
The distribution of Qi inside and outside depends on the season. The floating or sunken nature of facial color should correspond to the state of Qi. Therefore, one can infer the floating or sunken quality of color from the internal or external distribution of Qi, and conversely, infer the internal or external distribution of Qi from the floating or sunken quality of color. However, given such floating and sunken variations, what is the specific condition of the Qi and Color? I have heard that Heaven possesses the Five Elements (Wu Xing), which govern the four seasons to nurture and transform all things. In Spring, Liver Wood is prosperous, and the corresponding color should be Green (Qing). If the color is excessively prominent and clear-floating, this is termed "Excess" (Tai Guo), indicating disease located externally. If the color is faint and turbid-sunken, this is termed "Deficiency" (Bu Ji), indicating disease located internally. For Spring, luster/moisture (Ze) is the fundamental standard. During Spring, if the face is green with a lustrous appearance, like white silk wrapping dark blue-green pigment (Gao Guo Gan), it indicates health (Ping). If there is much green but little luster, it indicates disease. If there is only green without any luster, resembling dead grass, it indicates death.
In Summer, Heart Fire is prosperous, and the corresponding color should be Red (Chi). If the color is excessively prominent and clear-floating, this is termed "Excess," indicating disease located externally. If the color is faint and turbid-sunken, this is termed "Deficiency," indicating disease located internally. For Summer, luster is the fundamental standard. During Summer, if the face is red with a lustrous appearance, like white silk wrapping cinnabar (Gao Guo Zhu), it indicates health. If there is much red but little luster, it indicates disease. If there is only red without any luster, resembling congealed blood, it indicates death.
In Late Summer, Spleen Earth is prosperous, and the corresponding color should be Yellow (Huang). If the color is excessively prominent and clear-floating, this is termed "Excess," indicating disease located externally. If the color is faint and turbid-sunken, this is termed "Deficiency," indicating disease located internally. For Late Summer, luster is the fundamental standard. During Late Summer, if the face is yellow with a lustrous appearance, like white silk wrapping the color of Trichosanthes fruit (Gua Lou Shi), it indicates health. If there is much yellow but little luster, it indicates disease. If there is only yellow without any luster, resembling dried Zhi Shi (Aurantii Fructus), it indicates death.
In Autumn, Lung Metal is prosperous, and the corresponding color should be White (Bai). If the color is excessively prominent and clear-floating, this is termed "Excess," indicating disease located externally. If the color is faint and turbid-sunken, this is termed "Deficiency," indicating disease located internally. For Autumn, luster is the fundamental standard. During Autumn, if the face is white with a lustrous appearance, like white silk wrapping red (Gao Guo Hong), it indicates health. If there is much white but little luster, it indicates disease. If there is only white without any luster, resembling dry bones, it indicates death.
In Winter, Kidney Water is prosperous, and the corresponding color should be Black (Hei). If the color is excessively prominent and clear-floating, this is termed "Excess," indicating disease located externally. If the color is faint and turbid-sunken, this is termed "Deficiency," indicating disease located internally. For Winter, luster is the fundamental standard. During Winter, if the face is black with a lustrous appearance, like white silk wrapping purple (Gao Guo Zi), it indicates health. If there is much black but little luster, it indicates disease. If there is only black without any luster, resembling coal, it indicates death.
Regarding the colors of the four seasons above, attaining a balanced state means no disease; failing to attain balance results in disease. This is analogous to pulse diagnosis: Excess, solid, and strong pulses indicate disease arising externally; Deficiency, empty, and faint pulses indicate disease arising internally. However, seeing the appropriate color during its corresponding season is the norm (Chang); seeing it during a non-corresponding season is a variation (Bian). In variations, appearing before the season arrives or lingering after it leaves constitutes "Excess"; appearing after the season has passed or disappearing before it arrives constitutes "Deficiency." Excess leads to attacking the element one controls (Sheng) and overwhelming the element that controls one (Bu Sheng). Deficiency allows the controlled element to act recklessly, causes the element one generates to suffer illness, and invites bullying from the controlling element. Speaking in terms of generation and restriction: Color generating the Season is Empty Evil (Xu Xie); Season generating the Color is Solid Evil (Shi Xie); Color restricting the Season is Robbing Evil (Zei Xie); Season restricting the Color is Minor Evil (Wei Xie); Color matching the Season is Correct Evil (Zheng Xie - often interpreted as normal physiological response or mild pathogenic factor depending on context, here implying correspondence). The manifestations of the Five Colors can be deduced by analogy. The principles of Heavenly Stems and Earthly Branches regarding isolation, emptiness, prosperity, and phase can also be investigated according to method. Nevertheless, since diseases arise from three causes and Qi/Color follows ten methods, one must integrate these factors to understand their variations. Furthermore, when the climate does not match the season—such as winter being warm instead of cold, or summer being cool instead of hot; or when the season arrives but the climate has not, or the climate arrives but the season has not; or when the climate arrives but is excessive or deficient—if the Qi and Color correspond to this, it is following the time (Shun); if they do not correspond, it is opposing the time (Ni). These are further variations of the Four Seasons and Five Colors, where excess and deficiency can be observed through monitoring Qi.
When pathogenic Qi invades the body, it acts according to the principle of mutual overcoming. It heals when reaching the element it generates, worsens when reaching the element that overcomes it, stabilizes when reaching the element it generates (in a different context of progression), and arises when returning to its own position. One must first determine the colors and pulses of the Five Zang Organs to discuss the timing of improvement and worsening, as well as the periods of life and death. These are the essentials of observing the Four Seasons.