In Neijing("內經"), it explains heaven, earth, four seasons(天地四時) take part in human's birth, it gives influence on life support, and have organic relationship between body and movement of sun and earth(日月運行) of heaven and earth. Human body and the natural world corresponds, so the time changes in the natural world give immediate influence to human body, and correspond changes happen inside human body. This has no exception in qi of human(人氣), meridians, the viscera and organs(臟腑) and so on. In time, there are many kinds of cycles such as year, month, 10 days and a day. Yin and yang and the five elements in each cycle shows changes of prosperity and decay and transformation. In a year, there are spring, summer, late summer, fall and winter which are each included to wood, fire, earth, metal and water. Spring and summer belong to yang(陽), and fall and winter belong to yin(陰). A day can be divided into the crowing of the cook, dawn, noon, and twilight. After midnight yin falls and yang rises(陰盡陽生), and after noon yang falls and yin rises(陽盡陰生). Ups and downs of the qi and blood and human body change with time and the region of whereabout is different. In one month, when the moon is full qi of blood rises and when the moon comes down qi of blood falls. The qi of meridian(經氣) has a periodical changes with regular movement in meridian. This is a result of continuing movement of meridian and the nutrient(營) and the defense(衛) in human body, stars correspond with ups, and correspond with flow of water of meridian(經水) with downs. In a day the twelve meridians(十二經脈) in hour of yin(hours 3~5), it starts with qi and blood of lung meridian(手太陰肺經) prosperous, each qi and blood of meridian prosperous in order. In eight extra meridians(奇經八脈), Bideungpalbup(飛騰八法) per 5 days, Younggoopalbup(靈龜八法) per 60 days qi of pulse(脈氣) changes correspond. The qi and blood of five meridian points(五兪穴) is 5 days, so.