The most fundamental part consists of two parts, namely the lunar calendar months and the solar terms. Other parts are derived from these two parts. These include the following sections:
1. The lunar calendar month part (which also includes the heavenly stems and earthly branches of the lunar months, which is different from the stems and branches calendar mentioned later);
2. Solar terms and the seventy-two候 (sub-term periods);
3. Miscellaneous solar terms;
4. Stems and branches calendar [The Chinese lunar calendar's twelve zodiacal months (twelve solar terms), i.e., the Chinese zodiacal houses, is a part of the lunar calendar, based on the idea of the "Twelve Terms Calendar" by Shen Kuo of the Song Dynasty.
Note: The lunar calendar months correspond to the solar longitude degrees of the twelve major terms.
The calculation method of the stems and branches calendar in the Chinese lunar calendar is as follows: The starting point of the year's stems and branches is set at the exact time of the Start of Spring in the lunar calendar (note: not the 0 o'clock of the Start of Spring day). The starting point of each month's stems and branches is set at the exact time of the twelve solar terms (note: not necessarily the 0 o'clock of the corresponding solar term day). For daily recording, the continuous stems and branches system has been used for thousands of years in China. The twelve earthly branches for the hours are fixed, while the heavenly stems for the hour are derived from the day's heavenly stem.