Chinese calendar

The Chinese calendar is a lunisolar calendar formed by combining a purely lunar calendar with a solar calendar. Among Chinese, the calendar is not used for most day to day activities, but is used for the dating of holidays such as Chinese New Year and the Mid-Autumn Festival[?] and for divination. The primary use in day to day activities is for determining the phase of the moon, which is important for farmers and is possible because each day in the calendar corresponds to a particular phase of the month.

Ironically, the Chinese do not use the terms Chinese and Western calendar in Chinese. The Chinese name for the Chinese calendar is the farmer's calendar, and the Chinese name for the Western calendar is the civil calendar.

Table of contents 1 Calculations and Rules 2 Nomenclature 3 Twelve Animals 4 Jie Chi 5 Holidays

Calculations and Rules

The Chinese lunar calendar and the Julian Calendar often sync up every 19 years. Most Chinese people notice that their Chinese and Western birthdays often fall on the same day on their 19th, 38th birthday etc

The following rules for the Chinese Calendar (I believe) are equivalent to the rules as given by Helmer Alaksen. http://www.math.nus.edu.sg/aslaksen/calendar/chinese.shtml

These rules make use of the Tropical Zodiac familiar to Westerners. This must not be confused with the actual constellations corresponding to the 12 signs. The Chinese zodiac is completely different and is not used in the actual calculation of the calendar, but only in naming years. In fact, Chinese has a very different constellation system.

1. The months are lunar months, such that the first day of each month beginning 子时 (approximately 11 PM) is the day of the astronomical new moon.
2. Each year has 12 regular months, which are numbered in sequence (1 to 12). A year may also have an intercalary month (闰月), which may come after any regular month. It has the same number as the preceding regular month, but is designated intercalary.
3. The Chinese solar year (岁 sui4) is divided into 12 parts that are equivalent to the sun signs of the tropical zodiac.
4. Intercalary months are arranged so that, the sun always enters Capricorn on the 11th regular month (month 11) of a year.
5. If there are 12 months between two successive occurrences of month 11, one of these 12 months must be an intercalary month and it is the first of these 12 months during which the sun remains within the same zodiac sign throughout.
6. The times of the astronomical new moons and the sun entering a zodiac sign are determined in Chinese Time Zone by the Purple Mountain Observatory (紫金山天文台) in Nanjing.

The Zodiac Sign in which the sun is in at the start of the month usually determines the number of a regular month:

 Month  Zodiac Sign at Start
 11     Sagittarius (by rule 4)
 12     Capricorn
  1     Aquarius
  2     Pisces
  3     Aries
  4     Taurus
  5     Gemini
  6     Cancer
  7     Leo
  8     Virgo
  9     Libra
 10     Scorpio

Some astronomers believed this correspondence to be always true, but there are exceptions. An exception occurred in 1985, after the sun had entered Capricorn and then Aquarius in month 11, causing the Chinese New Year to occur on 20 February 1985 in Pisces rather than Aquarius.

The problem here is that there is a month in which the sun enters two signs of the zodiac. I'll refer to such a month as a dual-entry month. If a given month is a dual-entry month or has a dual-entry month before it and no earlier than the preceding month 11, the above correspondence may fail, otherwise it holds.

Nomenclature

The years are named by cycle of 10 Heavenly Stems (天干) and cycle of 12 Earthly Branches[?] (地支). Each year is named by a pair of one stem and one branch called Stem and Branch (干支). Heavenly Stems are associated with Yin Yang (阴阳) and 5 elements (五行). Earthly Branches are associated with 12 animals (see Twelve Animals section).

The 60-year cycle formed by combining the two cycles is known as a jiazi (甲子). It is not 120 because half of the combinations are unused. Jiazi is named after the first year in the 60-year cycle which is also called Jiazi. Some figures of speech use "jiazi" to mean "a full lifespan;" one who has lived more than a jiazi is obviously blessed. (Cf. the Biblical "three-score years and ten.")

This 60-year cycle is insufficient for historical references. During feudal China, the Nian Hao (Era name of an emperor) is add in front of year name for distinction. Example, 康熙壬寅 (kang1 xi1 ren2 yi2) (1662 AD) is the first 壬寅 (ren2 yi2) year during reign of 康熙 (kang1 xi1).

The months, day, and hours can also be denoted using Heavenly Stems and Earthly Branches, though they are commonly addressed using numerals instead. Together, the four Stem and Branch pairs form the Eight Characters (八字) used in Chinese astrology.

There is a distinction between solar year and lunar year in the Chinese calendar because the calendar is lunisolar. Lunar year (年 nian2) is from one Chinese new year to the next. Solar year (岁 sui4) is from one Start of Spring to the next (see Jie Chi section). Lunar year is used exclusively because dates are also in lunar.

Twelve Animals

The Twelve Animals (十二生肖 or colloquially called 十二属相) representing the 12 Earthly Branches (地支) are:

Rat

Ox

Tiger

Rabbit

Dragon

Snake

Horse

Sheep

Monkey

Rooster

Dog

Pig

This sequence is traditionally assigned according to a legend:

• One day, the twelve animals fought over the precedence of the animals in the cycle of years in the calendar. The Chinese gods held a contest to see which should be first: they all lined up on the bank of a river, and were given the simple task of getting to the opposite shore. Depending on arrival, the first to get there would get the first year, and the order would depend upon how fast they finished.