TCM Time-Based Differentiation: Yin-Yang Wellness Patterns

Chen is an ancient method of dividing day and night into equal parts. There are twelve divisions: Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, and Hai. Each division corresponds to a fixed time on the clock; for example, the Zi division spans from 11 p.m. to 1 a.m. the next morning. Among the twelve divisions, Zi and Wu represent the starting points and dividing lines of yin and yang, serving as a general term for yin and yang. Therefore, Zi and Wu hold special significance within the twelve divisions, symbolizing the transition from extreme yin to the birth of yang and from extreme yang to the emergence of yin, respectively. This discussion will now focus on the Zi and Wu divisions, as well as the patterns of wellness onset and yin-yang changes that occur during specific time intervals: from Zi to Wu, from Wu to Zi, from Zi to Mao, from Wu to You, from Mao to Wu, and from You to Zi.

1.The wellness occurs during the Zi and Wu periods, indicating a failure of smooth connection between yin and yang.

The period of Zichen (11 p.m. to 1 a.m.) represents the peak of yin energy when yang energy begins to emerge and yin energy starts to decline. The period of Wuchen (11 a.m. to 1 p.m.) represents the peak of yang energy when yin energy begins to emerge and yang energy starts to recede. When the waxing and waning of yin and yang in the human body aligns accordingly, no wellness occurs. However, if the waxing and waning of yin and yang within the human body fail to connect smoothly, various pathological changes may manifest during the periods of Zichen and Wuchen. When a wellness occurs solely during the period of Zichen, it is often due to yang deficiency failing to respond to the emergence of yang energy. The supports approach involves warming yang, primarily focusing on warming and nourishing the primordial yang of the Kidneys. Renqi Wan (Kidney Qi Pill) or Yougui Yin (Right-Restoring Decoction) can be used. When a wellness occurs solely during the period of Wuchen, it is often due to Yin Deficiency failing to respond to the growth of yin energy. The supports approach involves nourishing yin, primarily focusing on nourishing the primordial yin of the Kidneys. Liuwei Dihuang Wan (Six-Ingredient Rehmannia Pill) or Zuogui Yin (Left-Restoring Decoction) can be used. For wellness that manifest during both the periods of Zichen and Wuchen, it indicates a failure of yin and yang to connect smoothly, and the supports approach involves regulating yin and yang. Xiaochaihu Tang (Minor Bupleurum Decoction) or Guizhi Tang (Cinnamon Twig Decoction) can be selected. For instance, the late renowned traditional Chinese medicine practitioner Yue Meizhong introduced a case of Zichen-Wuchen obsession in his article “A Brief Understanding of Syndrome Differentiation and supports,” where he discussed the supports of such a condition.

The patient was a 10-year-old girl surnamed Ji. At the times of Zi (11 p.m. – 1 a.m.) and Wu (11 a.m. – 1 p.m.), she would experience involuntary limb flaccid paralysis, appearing as if she had lost consciousness and not responding to calls. After about an hour, she would wake up and be as normal as others. She was supports after taking two doses of Xiao Chai Hu Tang.

2.The wellness occurs from the zishi (23:00-1:00) to wushi (11:00-13:00) periods, indicating Yin Deficiency and qi weakness.

The Neijing states: “At the Winter Solstice, yang begins to rise; at the Summer Solstice, yin begins to rise.” Within a single day, the period from zi (11 PM to 1 AM) corresponds to the Winter Solstice of the year, while the period from wu (11 AM to 1 PM) corresponds to the Summer Solstice. If a person develops wellness from zi to wu but remains healthy from wu to zi, this is often due to yang qi deficiency, resulting in an inability to adapt to the natural rise of yang qi in the environment. Following the Neijing principle of “nourishing yang in spring and summer,” supports should focus on warming yang and replenishing qi.

Take Mr. Fan, male, aged 24, as an example. He had suffered from coughing from midnight to noon every day for two years. supports methods such as nourishing yin to clear the Lung, reinforcing earth to generate metal, resolving phlegm and ventilating the Lung with traditional Chinese medicine had all been ineffective. Based on the specific pattern that the cough occurred from midnight to noon, although there were no obvious signs of imbalance of yang deficiency, he was still supports with the method of warming and tonifying the Kidney yang. After taking nine doses of Yougui Decoction, the cough stopped. A follow-up six months later showed that he had recovered and the cough had not recurred.

3. The wellness occurs from noon to midnight, indicating Yin Deficiency and blood insufficiency.

From noon to midnight, yin qi begins to generate and gradually increases and becomes abundant. When yin and yang in the human body are in harmony, the body responds accordingly and remains free from wellness. If a person falls ill from noon to midnight but remains healthy from midnight to noon, it is mostly due to Yin Deficiency and blood insufficiency, failing to respond to the natural trend of yang decreasing and yin increasing in the environment. Based on the principle of nourishing yin in autumn and winter from the Inner Canon, the supports should focus on nourishing yin and replenishing blood.

For example, Mr. Zhang, male, 54 years old, had alternating chills and fever for half a month. He specifically felt chills after noon every day, developed fever at night, and the fever subsided with sweating at midnight. Given that the alternating chills and fever occurred regularly from noon to midnight, Gentiana Macrophylla and Amyda Sinensis Powder was prescribed to nourish yin and blood, expel pathogenic factors, and clear heat. After taking three doses, the alternating chills and fever completely subsided.

4.The wellness occurs between the Zi and Mao periods, with impaired ascendance and dispersion of the Shaoyang.

From the period of Zi to Mao is the latter half of the night, which belongs to yin within yang in terms of yin-yang theory. At the Zi hour, a trace of yang is generated. This trace of yang refers to lesser yang. The qi of lesser yang is generated at the Zi hour and reaches its peak at the Mao hour. When a wellness occurs specifically between the Zi and Mao hours, it indicates that the ascending and dispersing of the qi of lesser yang is impeded.

Take the case of Mr. Yan, male, 52 years old. He suffered from pain in the left hypochondrium extending to the gastric region from the period between midnight (Zi-Chen) and early morning (Mao-Chen) every night. The pain gradually worsened, necessitating him to get up and move around. The wellness had persisted for eight months. He was administered two doses of Xiao Chai Hu Tang, after which the pain ceased.

5.The wellness occurs between noon and dusk when yang qi fails to descend and submerge.

From noon to you (5–7 p.m.) is afternoon, which belongs to yang within yin in terms of yin-yang theory. The Inner Canon states: “As the sun sets in the west, yang qi becomes deficient, and the pores close.” Zhang Jingyue also believed that qi descends in the afternoon. When a wellness occurs exclusively between noon and you (5–7 p.m.), it is mostly due to the failure of yang qi to descend and submerge in a timely manner.

For example, a female patient surnamed Lu, aged 48, suffered from hypertension. She experienced dizziness and a flushed face from the afternoon to the period of you (5 – 7 p.m.) and chen (7 – 9 p.m.) every day. She was supports with a decoction modified from Zhi Bo Di Huang Wan (Anemarrhena, Phellodendron and Rehmannia Pill), to which Concha Margaritifera Usta (mother-of-pearl), Radix Paeoniae Alba (white peony root), and Radix Achyranthis Bidentatae (two-toothed achyranthes root) were added. After ten doses to nourish yin and subdue yang, her dizziness subsided and the flushed face disappeared.

6. wellness onset between the hours of Mao (5-7 a.m.) and Wu (11 a.m.-1 p.m.) indicates either Yang excess or Yang deficiency.

The period between 5-7 a.m. (Mao time) and 11 a.m.-1 p.m. (Wu time) is the morning, which belongs to the yang within yang in terms of yin-yang theory. Pathological manifestations during this period fall into two categories: First, when pathogenic factors are predominant, yang pathogens become even more excessive during the yang within yang period. For instance, as reported by Wang in Zhejiang Journal of Traditional Chinese Medicine (1980, Issue 4, Page 181), a patient suffered from upper fever for five to six days and was diagnosed with extreme heat due to hyperactivity of yang in the Liver and stomach. The administration of Baihu Decoction combined with Lingyang Gouteng Decoction resulted in the resolution of fever and recovery after one dose. Second, individuals with a yang-deficient constitution may develop wellness during this yang period despite it being an inappropriate time for their condition.

As recorded, the veteran TCM practitioner Yue Meizhong supports a woman who suffered from uterine bleeding every morning. He considered the condition to be caused by yang qi deficiency, resulting in the inability to restrain blood. He prescribed Siwu Decoction (Tangkuei Decoction for Blood Deficiency) with charred Zingiberis Rhizoma Preparatum (pao jiang), charred Aconiti Lateralis Radix Preparata (fu zi), and Cinnamomi Cortex (rou gui). After taking three doses, the uterine bleeding stopped. [New Journal of Traditional Chinese Medicine 76(6) 25]

7. wellness onset between the hours of You (5-7 PM) and Zi (11 PM-1 AM) indicates either Yin excess or Yin Deficiency.

The period between you (17:00-19:00) and zi (23:00-1:00) is the first half of the night, which belongs to yin within yin in terms of yin and yang. Pathogenesis at this time also has two situations. One is that when yin pathogens are latent internally, they become more severe and cause wellness when encountering yin within yin.

For example, a female patient surnamed Yao, aged 40, suffered from cough and asthma every evening (between 5 p.m. and 7 p.m., the period of You and Chen in the Chinese time system), with copious sputum, which would subside by midnight. This condition had recurred regularly for three to four years and had not responded to various Chinese and Western medications. After taking six doses of Xiao Qing Long Tang (Minor Blue Dragon Decoction) without Cinnamomi Ramulus (Guizhi), both the asthma and cough subsided. Another case involved a male patient surnamed Chen, aged 56, who was emaciated. Every day, starting from the period of You and Chen, he experienced a brief episode of chills, followed by fever until the period of Zi and Chen (between 11 p.m. and 1 a.m.), when he would sweat and the fever would subside. This condition had persisted for five days without response to antibiotic supports. After taking one dose of Liu Wei Di Huang Wan (Six-Ingredient Rehmannia Pill) with Sojae Semen Preparatum (Douchi) to nourish yin and expel pathogenic factors, the fever subsided and did not recur.