Changes

==Introduction==

==Introduction==

In 604 Japan adopted the Chinese calendar, <ref> E. Reishauer, et. al., ''East Asia: The Great Tradition'' (Boston: Houghton Mifflin, 1958), p. 476. Before that it appears that some kind of lunar calendar generally following the Chinese seasons was used, as can be seen from dates such as "Summer, the 4th month," "Winter, the 11th month" of the Nihon-gi ([[Nihon Shoki]])(pp. 37-44 of ''[[Sources of Japanese Tradition]]''). However, apparently it did not use the Chinese calculations. </ref> This calendar, or a modification of it, was used by Japan until 1873, when it adopted the Gregorian (modern Western) calendar as the official calendar. <ref> A standard Japanese lunar calender is still published and can be found in almanac-calendars and daily newspapers. However, it is ignored by most people. It is similar, but not identical to the modern Chinese lunar calendar. </ref>  However, as  almost all source materials for events in Japan before 1873 use the Japanese calendar, as do Japanese historians, this Wiki uses the Japanese calendar in principle. (See [[SamuraiWiki:About dates]].)

Japan came into contact with the Chinese calendar very early, but started calculating it and using fully about the beginning of the 7th century. <ref>The traditional date is 604. E. Reishauer, et. al., ''East Asia: The Great Tradition'' (Boston: Houghton Mifflin, 1958), p. 476. </ref> This calendar, or a modification of it, was used by Japan until 1873, when it adopted the Gregorian (modern Western) calendar as the official calendar. <ref> A Japanese lunar calendar is still published and can be found in almanac-calendars and daily newspapers. However, it is ignored by most people. It is similar, but not identical to the modern Chinese lunar calendar. </ref>  However, as  almost all source materials for events in Japan before 1873 use the Japanese calendar, as do Japanese historians, this Wiki uses the Japanese calendar in principle. (See [[SamuraiWiki:About dates]].)

Dates in Japanese are given as, for example, 10th month, 18th day (十月十八日). Though months do have names, in fact several names (though they are hardly ever used now), numbers are the principle month designations.

Dates in Japanese are given as, for example, 10th month, 18th day (十月十八日). Though months do have names, in fact several names (though they are hardly ever used now), numbers are the principle month designations.

==Characteristics of the Chinese calendar==

==Characteristics of the Chinese calendar==

The Chinese calendar, at least by the time it was adopted in Japan, was not an observational one ("There, we can see the new moon, so the month has started."), but a predictive one, based on calculations, as was necessary for a widely-spread out, developed beaurocracy. The calculation methods were revised at various times, both in China and Japan, so not everything below applies to all periods, especially the way of determining intercalary months.

The Chinese calendar, at least by the time it was adopted in Japan, was not an observational one ("There, we can see the new moon, so the month has started."), but a predictive one, based on calculations, as was necessary for a widely-spread out, developed bureaucracy. The calculation methods were revised at various times, both in China and Japan, so not everything below applies to all periods, especially the way of determining intercalary months.

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 solstices, in the Chinese calendar, the start of spring (立春) is exactly half-way between the winter solstice and the spring equinox, and similarly for other seasons.

Among the characteristics of the Chinese-type calender are the following:

Among the characteristics of the Chinese-type calender are the following:

*Months start on the day of the new moon.  

*Months start on the day of the astronomical new moon, that is when the sun and moon are aligned and solar eclipses can occur. <ref>The calendar used in Japan in the seventh century used the average length of lunar months, but later ones tried to calculate the exact moment of the new moon.</ref> (In contrast, the Ancient Near Eastern calendars started the month the evening after the crescent moon was seen, several days after the astronomical new moon.)

*Months are either 29 (''Shô no tsuki'' 小の月)or 30 days (''Dai no tsuki'' 大の月) 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  '''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 (''Shô no tsuki'' 小の月) or 30 days (''Dai no tsuki'' 大の月) long.  This means that the date 2/30 is possible, whereas 3/31 is not.  Unlike some other calendars, it is  '''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. Normally, but frequently not, 29-day and 30-day months alternate.  

   

   

*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" (節気 ''sekki'') such as the "Great Cold". 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 solstice, the spring equinox, the sumer solstice, the autumn solstice, and two points between each. <ref> The year is also divided into 24 "solar terms" (節気 ''sekki'') such as the "Great Cold."  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 solstice 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 year. 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 '''Intercalary Months'''.

*Because the lunar month is less than 1/12 of a solar year, sometimes a month falls entirely between the solar points  (中気). <ref>After 1844 the method of calculating the solar points changed, and there could be two in one month. In such cases the designations of the months were arranged so that the month with the winter solstice was the 11th month.</ref> In such cases the month is called an intercalary (閏 uruu) month, and is given the same number as the previous month. For more, see below on '''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. There were also difference in whether to use average or actual lengths. For example, by the end of the 16th century the new year started between Jan. 24 and Feb. 24.

*The first month (New Year) is the month that has the second solar point after the winter solstice. Thus New Year Day is usually the day of the new moon nearest to the first day of spring, about Feb. 4  (see above on the starts of seasons). In the present Japanese modern lunar calendar, New Years Day is between about Jan. 21 and Feb. 19. <ref> Because both the western calendar and the Japanese calendar have changed in relation to the solar year over time, the possible dates vary with the period. For example, towards the end of the 16th century the new year started between Jan. 24 and Feb. 24.</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  [[Ako ronin|Akô rônin]] carried out their revenge on Genroku 15 (1702).12.15, which was Jan. 31, 1703 , so one sees both 1702 and 1703 as the date.

===Intercalary Months===

===Intercalary Months===

As the solar year is about 365.25 days but 12 lunar months last only about 354, each year the months start about 11 days earlier with respect to the solar calendar (the seasons) as they did the previous year.  In fact, in about two years and eight months, the calendar moves a full month ahead.<ref> The Islamic calendar does not have intercalary months, so any given month changes its season year by year. There is no way of knowing the season of any month except by checking on a chart of that year.</ref> In order to keep the lunar and solar calendar from getting too far apart, as noted in the characteristics above, when the month gets a full month ahead,  the month is given the same number as the preceeding month, but is called an "閏 (''uruu'')" month. For example, if there are two "third months," the first is called just "third month," but the next is called the "uruu third month". In this Wiki it is refered to as "'''int. 3'''", for "intercalary 3rd month".  Thus,  1599/3 was followed by 1599/int. 3, which was followed by 1599/4. This type of intercalary month, which can happen any month in the year, is a feature of the Chinese-type luni-solar calendar.

As the solar year is about 365.25 days but 12 lunar months last only about 354, each year the months start about 11 days earlier with respect to the solar calendar (the seasons) as they did the previous year.  In fact, in about two years and eight months, the calendar moves a full month ahead.<ref> The Islamic calendar does not have intercalary months, so any given month changes its season year by year. There is no way of knowing the season of any month except by checking on a chart of that year.</ref> In order to keep the lunar and solar calendar from getting too far apart, as noted in the characteristics above, when the month gets a full month ahead,  the month is given the same number as the preceding month, but is called an "閏 (''uruu'')" month. For example, if there are two "third months," the first is called just "third month," but the next is called the "uruu third month". In this Wiki it is referred to as "'''int. 3'''", for "intercalary 3rd month".  Thus,  1599/3 was followed by 1599/int. 3, which was followed by 1599/4. This type of intercalary month, which can happen any month in the year, is a feature of the Chinese-type luni-solar calendar.

 

 

 

 

However, I have not seen dates given in cyclic days most other places I have looked--the [[Heian Period]] literary works, a few Muromachi Period graves and steles, [[Azuchi-Momoyama Period]] letters and Edo period bureaucratic letters and records. Many of them give the cyclic year. But letters read like, "Your letter of the past 21st reached here the 27th," or "I am leaving the coming 24th, so accompany me," with no mention of the cyclic date in the text or in the letter date.

Would it not have been easier just to have thirteen months sometimes instead of sometimes having two 5th months, for example?  This is how the luni-solar ancient Babylonian and Jewish calendars work.  However, the Chinese calendar keeps months near where they should be. For example, In 1583 there was an int. 1st month. That meant that the second month started on March 24 instead of Feb. 23.  March 24th is within the normal starting period for the the 2nd month during that time, but Feb. 23 would have been early for the 2nd month. The 12th month started Jan. 13, 1584, also within the normal time frame for the 12th month. But if there had been no intercalary month, all the months of the year after the first would have started too early, and the 12th month would have started Dec. 14, though months that started from about Nov. 26 to Dec. 23 were supposed to be the 11th month. Thus, the Chinese calendar method keeps the months tightly connected to the solar year and prevents overlaps in the periods in which months can begin.

That is not to say that the cyclic days, especially the '''shi''' of the days were not important in daily life. For example, the Heian Period had many customs and superstitions related to cyclic days ([[The World of the Shining Prince|Morris's ''The World of the Shining Prince'']]). A tree in a shrine was planted "in the Hour of the Bird, on the Day of the Bird, in the Year of the Bird." Edo period pocket calendars indicated the cyclic designations of some days. One custom that has survived to the present is that a pregnant woman should first put on, or at least purchase, a maternity girdle on a day of the dog. However, few calendars now include the cyclic days.

==Calculation Website ==

==Calculation Website ==

Unlike conversions between era years and Western years, which is a fairly easy calculation (see [[Year dates]] and [[Japanese Eras]], conversion between the Western and Chinese calendar can only be done using a monthly table based on historical documents. One table is Tuchihashi's.  However, now there are several websites that provide calcuators which look up dates.  One is the following:

Unlike conversions between era years and Western years, which is a fairly easy calculation (see [[Year dates]] and [[Japanese Eras]]), conversion between the Western and Chinese calendar can only be done using a monthly table based on historical documents. One table is Tuchihashi's.  However, now there are several websites that provide calculators which look up dates.  One is the following:

http://www.uni-tuebingen.de/geschichte-japans/nengo_calc.htm which will give the Western year for the Japanese date.

http://www.uni-tuebingen.de/geschichte-japans/nengo_calc.htm which will give the Western year for the Japanese date.