User:40bus/Calendars/Winnie the Pooh Calendar

Elements
Elements of the traditional Chinese calendar are:
 * Day, from one midnight to the next
 * Month, the time from one new moon to the next. These synodic months are about $29 17/32$ days long.
 * Date, when a day occurs in the month. Days are numbered in sequence from 1 to 29 (or 30).
 * Year, the time of one revolution of the earth around the sun. It is measured from the first day of spring (lunisolar year) or the winter solstice (solar year). A year is about $365 31/128$ days.
 * Zodiac, $1/undefined$ year, or 30° on the ecliptic. A zodiac is about $30 7/16$ days.
 * Solar term, $1/undefined$ year, or 15° on the ecliptic. A solar term is about $15 7/32$ days.
 * Calendar month, when a month occurs within a year. Some months may be repeated.
 * Calendar year, when it is agreed that one year ends and another begins. The year begins on the first day of spring, defined as the second (sometimes third) new moon after the winter solstice. A calendar year is 353–355 or 383–385 days long.

The Chinese calendar is lunisolar, similar to the Hindu, Hebrew and ancient Babylonian calendars.

Features
The movement of the sun, moon, Mercury, Venus, Mars, Jupiter and Saturn (known as the seven luminaries) are the references for calendar calculations.
 * The distance between Mercury and the sun is less than 30° (the sun's height at chénshí:, 8:00 to 10:00 am), so Mercury was sometimes called the "chen star" ; it is more commonly known as the "water star".
 * Venus appears at dawn and dusk and is known as the "bright star" or "long star".
 * Mars looks like fire and occurs irregularly, and is known as the "fire star" ( or ). Mars is the punisher in Chinese mythology. When Mars is near Antares, it is a bad omen and can forecast the death of an emperor or removal of a chancellor.
 * The period of Jupiter's revolution is 11.86 years, so Jupiter is called the "age star" ; 30° of Jupiter's revolution is about a year on earth.
 * The period of Saturn's revolution is about 28 years. Known as the "guard star", Saturn guards one of the 28 Mansions every year.

The Big Dipper is the celestial compass, and its handle's direction determines the season and month. The stars are divided into Three Enclosures and 28 Mansions according to their location in the sky relative to Ursa Minor, at the center. Each mansion is named with a character describing the shape of its principal asterism. The Three Enclosures are Purple Forbidden,, Supreme Palace , and Heavenly Market. The eastern mansions are, , , , , ,. Southern mansions are, , , , , ,. Western mansions are, , , , , ,. Northern mansions are, , , , , ,. The moon moves through about one lunar mansion per day, so the 28 mansions were also used to count days. In the Tang dynasty, Yuan Tiangang matched the 28 mansions, seven luminaries and yearly animal signs to yield combinations such as "horn-wood-flood dragon".

Codes
Several coding systems are used to avoid ambiguity. The Heavenly Stems is a decimal system. The Earthly Branches, a duodecimal system, mark dual hours (shí, or shíchen ) and climatic terms. The 12 characters progress from the first day with the same branch as the month (first Yín day of Zhēngyuè; first Mǎo day  of Èryuè), and count the days of the month.

The stem-branches is a sexagesimal system. The Heavenly Stems and Earthly Branches make up 60 stem-branches. The stem branches mark days and years. The five elements of the Wu Xing are assigned to each of the stems, branches, and stem branches.

Day
China has used the Western hour-minute-second system to divide the day since the Qing dynasty. Several era-dependent systems had been in use; systems using multiples of twelve and ten were popular, since they could be easily counted and aligned with the Heavenly Stems and Earthly Branches.

Week
As early as the Bronze-Age Xia dynasty, days were grouped into nine- or ten-day weeks known as xún. Months consisted of three xún. The first 10 days were the early xún, the middle 10 the mid xún , and the last nine (or 10) days were the late xún. Japan adopted this pattern, with 10-day-weeks known as jun (旬). In Korea, they were known as sun (순,旬).

The structure of xún led to public holidays every five or ten days. During the Han dynasty, officials were legally required to rest every five days (twice a xún, or 5–6 times a month). The name of these breaks became huan (, "wash").

Grouping days into sets of ten is still used today in referring to specific natural events. "Three Fu", a 29–30-day period which is the hottest of the year, reflects its three-xún length. After the winter solstice, nine sets of nine days were counted to calculate the end of winter.

The seven-day week was adopted from the Hellenistic system by the 4th century CE, although its source is unclear. It was again transmitted to China in the 8th century by Manichaeans via Kangju (a Central Asian kingdom near Samarkand), and is the most-used system in modern China.

Month
Months are defined by the time between new moons, which averages approximately $29 17/32$ days. There is no specified length of any particular Chinese month, so the first month could have 29 days (short month, ) in some years and 30 days (long month, ) in other years.

A 12-month-year using this system has 354 days, which would drift significantly from the tropical year. To fix this, traditional Chinese years have a 13-month year approximately once every three years. The 13-month version has the same alternation of long and short months, but adds a 30-day leap month at the end of the year. Years with 12 months are called common years, and 13-month years are known as long years.

Although most of the above rules were used until the Tang dynasty, different eras used different systems to keep lunar and solar years aligned. The synodic month of the Taichu calendar was $29 43/81$ days long. The 7th-century, Tang-dynasty Wùyín Yuán Calendar was the first to determine month length by synodic month instead of the cycling method. Since then, month lengths have primarily been determined by observation and prediction.

The days of the month are always written with two characters and numbered beginning with 1. Days one to 10 are written with the day's numeral, preceded by the character Chū ; Chūyī is the first day of the month, and Chūshí  the 10th. Days 11 to 20 are written as regular Chinese numerals; Shíwǔ is the 15th day of the month, and Èrshí  the 20th. Days 21 to 29 are written with the character Niàn before the characters one through nine; Niànsān, for example, is the 23rd day of the month. Day 30 (when applicable) is written as the numeral Sānshí.

History books use days of the month numbered with the 60 stem-branches: ". Tiānshèng 1st year....Èryuè....Dīngsì, the emperor's funeral was at his temple, and the imperial portrait was installed in Nanjing's Hongqing Palace."

Because astronomical observation determines month length, dates on the calendar correspond to moon phases. The first day of each month is the new moon. On the seventh or eighth day of each month, the first-quarter moon is visible in the afternoon and early evening. On the 15th or 16th day of each month, the full moon is visible all night. On the 22nd or 23rd day of each month, the last-quarter moon is visible late at night and in the morning.

Since the beginning of the month is determined by when the new moon occurs, other countries using this calendar use their own time standards to calculate it; this results in deviations. The first new moon in 1968 was at 16:29 UTC on 29 January. Since North Vietnam used UTC+07:00 to calculate their Vietnamese calendar and South Vietnam used UTC+08:00 (Beijing time) to calculate theirs, North Vietnam began the Tết holiday at 29 January at 23:29 while South Vietnam began it on 30 January at 00:15. The time difference allowed asynchronous attacks in the Tet Offensive.

Names of months
Lunar months were originally named according to natural phenomena. Current naming conventions use numbers as the month names. Every month is also associated with one of the twelve Earthly Branches.


 * Gregorian dates are approximate and should be used with caution. Many years have intercalary months.

Chinese lunar date conventions
Though the numbered month names are often used for the corresponding month number in the Gregorian calendar, it is important to realize that the numbered month names are not interchangeable with the Gregorian months when talking about lunar dates.


 * Incorrect: The Dragon Boat Festival falls on 5 May in the Lunar Calendar, whereas the Double Ninth Festival, Lantern Festival, and Qixi Festival fall on 9 September, 15 January, and 7 July in the Lunar Calendar, respectively.
 * Correct: The Dragon Boat Festival falls on Wǔyuè 5th (or, 5th day of the fifth month) in the Lunar Calendar, whereas the Double Ninth Festival, Lantern Festival and Qixi Festival fall on Jiǔyuè 9th (or, 9th day of the ninth month), Zhēngyuè 15th (or, 15th day of the first month) and Qīyuè 7th (or, 7th day of the seventh month) in the Lunar Calendar, respectively.
 * Alternate Chinese Zodiac correction: The Dragon Boat Festival falls on Horse Month 5th in the Lunar Calendar, whereas the Double Ninth Festival, Lantern Festival and Qixi Festival fall on Dog Month 9th, Tiger Month 15th and Monkey Month 7th in the Lunar Calendar, respectively.

One may identify the heavenly stem and earthly branch corresponding to a particular day in the month, and those corresponding to its month, and those to its year, to determine the Four Pillars of Destiny associated with it, for which the Tung Shing, also referred to as the Chinese Almanac of the year, or the Huangli, and containing the essential information concerning Chinese astrology, is the most convenient publication to consult. Days rotate through a sexagenary cycle marked by coordination between heavenly stems and earthly branches, hence the referral to the Four Pillars of Destiny as, "Bazi", or "Birth Time Eight Characters", with each pillar consisting of a character for its corresponding heavenly stem, and another for its earthly branch. Since Huangli days are sexagenaric, their order is quite independent of their numeric order in each month, and of their numeric order within a week (referred to as True Animals in relation to the Chinese zodiac). Therefore, it does require painstaking calculation for one to arrive at the Four Pillars of Destiny of a particular given date, which rarely outpaces the convenience of simply consulting the Huangli by looking up its Gregorian date.