Changes

The Chinese calendar is a lunar, actually a luni-solar, calendar. The start of the month is determined by the new moon, but the position of the month in the year is determined by the solar year, that is, course of the seasons. One should note that although in the the West seasons are considered to begin on the equinoxes and solistices, in the Chinese calendar, the start of spring (立春) is exactly half-way between the winter solistice and the spring equinox, and similarly for other seasons.

The Chinese calendar is a lunar, actually a luni-solar, calendar. The start of the month is determined by the new moon, but the position of the month in the year is determined by the solar year, that is, course of the seasons. One should note that although in the the West seasons are considered to begin on the equinoxes and solistices, in the Chinese calendar, the start of spring (立春) is exactly half-way between the winter solistice and the spring equinox, and similarly for other seasons.

Among the characteristics of the Chinese-type calender are the following: <ref Dates below are given in the modern calendar. Also, as Japan is 9 hours east of Greenwich, some years the seasonal date is one day later than that given below.  /ref>

Among the characteristics of the Chinese-type calender are the following: <ref Dates below are given in the modern calendar. Also, as Japan is 9 hours east of Greenwich, some years the seasonal date is one day later than that given below.  </ref>

Months start on the day of the new moon.  

Months start on the day of the new moon.  

Months are either 29 or 30 days long. Normally, but not always, 29-day and 30-day months alternate.  This means that the date 2/30 is possible, whereas 3/31 is not.  Unlike many other calendars, it is [bold] not the case that a particular month is normally a particular length. There is no way of knowing whether a month is 29 or 30 days long except by looking at the calendar for a particular year.

Months are either 29 or 30 days long. Normally, but not always, 29-day and 30-day months alternate.  This means that the date 2/30 is possible, whereas 3/31 is not.  Unlike many other calendars, it is [bold] not the case that a particular month is normally a particular length. There is no way of knowing whether a month is 29 or 30 days long except by looking at the calendar for a particular year.

The first month (New Year) starts on the new moon nearest to the first day of spring, Feb. 4  (see above on the starts of seasons).  Thus the first month  starts between Jan. 20 and Feb. 20. <ref>This means dates towards the end of the Japanese year are in the next year of the Western calendar.  For instance, the death of the [[Twenty-Six Martyrs of Japan]] was 1596/12/19, but it is better known by the Western date of Feb. 5, 1597.  The [[Akô rônin]] carried out their revenge on Genroku 15 (1702).12.14, which was Jan. 30, 1703 , so one sees both 1702 and 1703 as the date.

The first month (New Year) starts on the new moon nearest to the first day of spring, Feb. 4  (see above on the starts of seasons).  Thus the first month  starts between Jan. 20 and Feb. 20. <ref>This means dates towards the end of the Japanese year are in the next year of the Western calendar.  For instance, the death of the [[Twenty-Six Martyrs of Japan]] was 1596/12/19, but it is better known by the Western date of Feb. 5, 1597.  The [[Akô rônin]] carried out their revenge on Genroku 15 (1702).12.14, which was Jan. 30, 1703 , so one sees both 1702 and 1703 as the date.

The calendar also takes into account the solar year. The solar year is divided into twelve periods by twelve solar points (中気　chûki) : the winter solistice, the spring equinox, the sumer solistice, the autumn solistice, and two points between each. <ref> The year is also divided into 24 "solar terms" such as These are the 12 chûki plus the 12 points that are half-way between chûki. </ref> The months are numbered according to the solar point that occurs during that month.  For example, the month in which the winter solistice occurs is the 11th month, and the one in which the spring equinox occurs is the 2nd month.

The calendar also takes into account the solar year. The solar year is divided into twelve periods by twelve solar points (中気　chûki) : the winter solistice, the spring equinox, the sumer solistice, the autumn solistice, and two points between each. <ref> The year is also divided into 24 "solar terms" such as These are the 12 chûki plus the 12 points that are half-way between chûki. </ref> The months are numbered according to the solar point that occurs during that month.  For example, the month in which the winter solistice occurs is the 11th month, and the one in which the spring equinox occurs is the 2nd month.

Because the lunar month is less than 1/12 of a solar month. sometimes a month falls entirely between the solar points  (中気). In such cases the month is called an intercalary (閏 urru) month, and is given the same number as the previous month. For more, see below on [Bold] Intercalary Months.

Because the lunar month is less than 1/12 of a solar month. sometimes a month falls entirely between the solar points  (中気). In such cases the month is called an intercalary (閏 urru) month, and is given the same number as the previous month. For more, see below on [Bold] Intercalary Months.

Note that sometimes other rules took precendence over those above. It should also be noted that as the calendar was predictive, over time it got removed from astronomical realitiy. For example, by the end of the 16th century the new year started between Jan. 24 and Feb. 24.

Note that sometimes other rules took precendence over those above. It should also be noted that as the calendar was predictive, over time it got removed from astronomical realitiy. For example, by the end of the 16th century the new year started between Jan. 24 and Feb. 24.