Objective: To explore the original meaning of concept of shichen in acupoint selection according to time of "needling methods of midnight-noon ebb-flow (Ziwu Liuzhu)" and "eight methods of the intelligent turtle (Linggui Bafa)", so as to provide more scientific and accurate calculating method for acupoint selection according to time in clinical acupuncture and moxibustion.
Methods: Based on the theory of "Heaven-people corresponding", use modern calculating time method to return to the ancient traditional concept of shichen. Compared ancient and modern calculating time methods of shichen and referred to sundial time-calculating method, in combination with changes of day and night time in 24 solar terms, use modern time-calculating method to calculate, so as to deny the mechanical time-calculating method of heavenly stems and earthly branches, in which each shichen is equal to 2 hours and it has been used from the last stage of the Ming dynasty and the initial stage of the Qing dynasty up to now.
Results: Return to the original meaning of shichen in acupoint selection according to time, and time of each shichen should change along with changes of day and night time in the four seasons of one year.
Conclusion: The concrete calculating method of shichen for different stages of four seasons in one year should be different.