Is each month divided into twelve solar terms or the first day of the first year?

Strictly speaking, the cutting boundary of year or month is inseparable from the festivals in the twelve solar terms. The boundary between years is based on the beginning of spring in the 24 solar terms (including the division between the twelfth month of the previous year and the first month of that year). The division between months is also based on the solar terms of the 24 solar terms to determine the moon column (month).

Both the annual column and the monthly column are arranged according to the festivals in the 24 solar terms (excluding gas) in the calendar.

The annual columns are determined according to the vertical nodes of beginning of spring in calendar science, and the arrangement of the monthly columns is also determined according to the vertical nodes of the twenty-four solar terms.