The identity card of Shaanxi people is the lunar calendar.

The date on the ID card is the date on the birth certificate, and it is based on the solar calendar, which is unified throughout the country.

Lunar calendar, the traditional calendar of China. According to the cycle of the moon phase, each moon phase changes to one month. A tropical year is divided into 24 segments, forming 24 solar terms. By referring to the tropic year of the sun, leap months are set to adapt their average calendar year to the tropic year. The lunar calendar combines the lunar calendar with the solar calendar to form a method of combining yin and yang.