Chinese Lunar Calendar: The Characteristics

The Chinese lunar calendar has the following characteristics:

1)  The lunar calendar month is based on the cycle of the moon around the earth.  Since the length of the synodic cycle is 29.53 days, each lunar calendar month alternately has either 29 or 30 days.

2)  Since every solar year has 12 lunatic cycles, every lunar year has (29.53 * 12 =) 354.37 days.  So, a lunar year is about 11 days shorter than a solar year.

3)  The Chinese lunar calendar is not a "pure" lunar calendar (which would have exactly 12 lunar months in a year):  In addition to taking into account the cycles of the moon around the earth, it also synchronizes with the solar year, ie, the new year starts on the second new moon after the winter solstice.  Since every solar year has 365.24 days, every lunar year has (365.24 / 29.53 =) 12.369 months.  To synchronize with the solar cycle, the Chinese lunar year has one "leap" month added to the year every 2-3 years.  (Hence, this calendar system is actually lunisolar.)  So, the Chinese calendar month is lunar, whereas the Chinese calendar year is solar.

4)  The first day of the Chinese lunar month is always the day of the new moon.

5)  All calculations involving the Chinese calendar must be based on longitude 120 east, which corresponds to the east coast of China.