According to the theory of traditional Chinese medicine, Tang Yin is a place where people's yang is gathered, and it is also a meeting place of people's internal organs and qi and blood. When the human body is in a healthy state, most of the circles on the Tang Yin are small and bright; However, when the human body is affected by bad factors, it will lead to abnormal situations such as the increase of Tang Yin circle and uneven brightness. Therefore, by observing the circle on the Tang Yin, we can get a preliminary understanding of human health.
The circle on the Tang Yin can reflect a person's psychological state. When the mood is stable and the mood is quiet, the circle is mostly small and bright. On the contrary, it will become irregular, dim or even disappear. Therefore, by observing the circle on the Tang Yin, we can not only explore people's physical health, but also understand the individual's internal emotional state, which is an important indicator to maintain physical and mental health.