Chinese dating system
One solar year is either the period between one Vernal Equinox and the next or the period between two Winter Solstices.In the Chinese calendar there are two different month cycles.
The Chinese calendar divides the year into 24 solar segments according to the Sun’s positions on the tropical zodiac.
The solar months are defined by the longitudes of the Sun.
A lunisolar calendar is a lunar calendar that keeps months on a lunar cycle, but then intercalary months are added to bring the lunar cycles into synchronisation with the solar year.
The reason for this is that a year is not evenly divisible by an exact number of lunations, so without the addition of intercalary months the seasons will drift each year.
The months of the Chinese calendar are numbered by the Principal Term that falls within it (see below).
The Chinese solar months are not like the months of a ‘modern’ calendar.Month 1, 正月, zhēngyuè, literally means principal month (first moon).All other months are literally numbered, second month, third month, etc.The Sexagenarian cycle for recording days was already in use.Tradition holds that, in that era, the year began on the first new moon after the Winter Solstice.One uses the lunar system and the other uses the solar system.