Calendar system in Japan
This article describes about calendar system in Japan, and how the date was represented in this wiki.
- 1 Japanese old style calender before 1873
- 2 Date in this wiki
- 3 Sexagenary cycle
- 4 transform table
- 5 Other calendar systems
- 6 reference
Japanese old style calender before 1873
In Japan, Gregorian Calendar system was adopted from 1st January, 1873. Before the day, lunisolar calendar system has been applied.
leap monthsIn lunisolar calendar, a month consists 29 or 30 days. The length of month may vary yearly or monthly.
One year contains 12 months usually, but it is much shorter than solar year (365/366 days). To adjust the gap, the leap month was inserted 7 times in 19 years. For example, in 1868 "leap April" was inserted after the "normal" April. So the year 1868 has 13 months.
name of months
In Japan, each month of year does not have individual name, it is simply called "First month", "Second month", etc. This rule also applies currently. In this wiki, the name of month would be described in English form (Jan, Feb, etc.) even for lunisolar calendar date.
calendar date in high ancient Japan
Lunisolar calendar system was imported from China, around 6th or 7th century. Old records edited in 8th century describes about the historical event with specific date for BC 7th century in earliest, historians unveiled that such dates were reverse-calculated using calendar calculating method in that age (8th century). Therefore such dates must be fictional until the later years of Emperor Kimmei's reign (ended 571).
Date in this wikiAs for the date after 1873, all the date would be described with Gregorian calendar, unless with any notification. Before the date, usually two form of date would be described simultaneously, for example:
2 Dec 1872OS / 31 Dec 1872NS
This example shows the date "2 Dec 1872 in lunisolar calendar (Old Style - OS)" corresponds "31 Dec 1872 in Gregorian calendar (New Style - NS)".
Now in progress to expand date expression
As this Wiki is going to cover much wider range of historical event, I will expand date expression to provide more apparent and avoid-misunderstanding way. The suffixes following to date is now to be:
- JOS - Japanese Old Style. By lunisonar calender system which was adopted in Japan until 1873.
- JC - Julian Calender. Used before 1582 (Western Catholic Countries), 18th century (Western Protestant Countries), 20th century (Russia and Eastern Countries).
- GC - Gregorian Calender. Started to use on 1582 in Western Catholic Countries. Adopted in Japan from 1873. Current de facto standard calendar system in the world.
- LS - Local Style. Other than above.
Without any suffix, the date should be treated as expressed by the Gregorian Calendar.
Sexagenary cycle is counting system used for day, month (rarely) or year, originally created in ancient China and widely used in far eastern countries. It is expressed by combination of 10 stems and 12 branches, these creates 60 (least common multiple of 10 and 12) numbers in a cycle.
10 stems are also created as combinations of 5 elements (wood, fire, earth, metal, water) and "positive and negative". In Japan, "positive and negative" are corresponded to "senior brother" 兄 -no-e and "junior brother" 弟 -no-to.
in the wiki
12 branches are expressed by symbol beast, with following sequence:
stems and branches
Combination of stems and branches created a cycle of 60 (days or years).
|no||Kanji||Jap'd Chinese||Japanese||English||no||Kanji||Jap'd Chinese||Japanese||English||no||Kanji||Jap'd Chinese||Japanese||English||no||Kanji||Jap'd Chinese||Japanese||English||no||Kanji||Jap'd Chinese||Japanese||English|
|1||甲子||Koo-shi||Ki-no-e Ne||Rat, senior wood||2||乙丑||Itsu-chu||Ki-no-to Ushi||Ox, junior wood||3||丙寅||Hei-in||Hi-no-e Tora||Tiger, senior fire||4||丁卯||Tei-bo||Hi-no-to U||Rabbit, junior fire||5||戊辰||Bo-shin||Tsuchi-no-e Tatsu||Dragon, senior earth|
|6||己巳||Ki-shi||Tsuchi-no-to Mi||Snake, junior earth||7||庚午||Koo-go||Ka-no-e Uma||Horse, senior metal||8||辛未||Shin-bi||Ka-no-to Hitsuji||Goat, junior metal||9||壬申||Jin-shin||Mizu-no-e Saru||Monkey, senior water||10||癸酉||Ki-yu||Mizu-no-to Tori||Rooster, junior water|
|11||甲戌||Ko-jutsu||Ki-no-e Inu||Dog, senior wood||12||乙亥||Itsu-gai||Ki-no-to I||Pig, junior wood||13||丙子||Hei-shi||Hi-no-e Ne||Rat, senior fire||14||丁丑||Tei-chu||Hi-no-to Ushi||Ox, junior fire||15||戊寅||Bo-in||Tsuchi-no-e Tora||Tiger, senior earth|
|16||己卯||Ki-bo||Tsuchi-no-to U||Rabbit, junior earth||17||庚辰||Koo-shin||Ka-no-e Tatsu||Dragon, senior metal||18||辛巳||Shin-shi||Ka-no-to Mi||Snake, junior metal||19||壬午||Jin-go||Mizu-no-e Uma||Horse, senior water||20||癸未||Ki-bi||Mizu-no-to Hitsuji||Goat, junior water|
|21||甲申||Koo-shin||Ki-no-e Saru||Monkey, senior wood||22||乙酉||Itsu-yu||Ki-no-to Tori||Rooster, junior wood||23||丙戌||Hei-jutsu||Hi-no-e Inu||Dog, senior fire||24||丁亥||Tei-gai||Hi-no-to I||Pig, junior fire||25||戊子||Bo-shi||Tsuchi-no-e Ne||Rat, senior earth|
|26||己丑||Ki-chu||Tsuchi-no-to Ushi||Ox, junior earth||27||庚寅||Koo-in||Ka-no-e Tora||Tiger, senior metal||28||辛卯||Shin-bo||Ka-no-to U||Rabbit, junior metal||29||壬辰||Jin-shin||Mizu-no-e Tatsu||Dragon, senior water||30||癸巳||Ki-shi||Mizu-no-to Mi||Snake, junior water|
|31||甲午||Koo-go||Ki-no-e Uma||Horse, senior wood||32||乙未||Itsu-bi||Ki-no-to Hitsuji||Goat, junior wood||33||丙申||Hei-shin||Hi-no-e Saru||Monkey, senior fire||34||丁酉||Tei-yu||Hi-no-to Tori||Rooster, junior fire||35||戊戌||Bo-jutsu||Tsuchi-no-e Inu||Dog, senior earth|
|36||己亥||Ki-gai||Tsuchi-no-to I||Pig, junior earth||37||庚子||Koo-shi||Ka-no-e Ne||Rat, senior metal||38||辛丑||Shin-chu||Ka-no-to Ushi||Ox, junior metal||39||壬寅||Jin-in||Mizu-no-e Tora||Tiger, senior water||40||癸卯||Ki-bo||Mizu-no-to U||Rabbit, junior water|
|41||甲辰||Koo-shin||Ki-no-e Tatsu||Dragon, senior wood||42||乙巳||Itsu-shi||Ki-no-to Mi||Snake, junior wood||43||丙午||Hei-go||Hi-no-e Uma||Horse, senior fire||44||丁未||Tei-bi||Hi-no-to Hitsuji||Goat, junior fire||45||戊申||Bo-shin||Tsuchi-no-e Saru||Monkey, senior earth|
|46||己酉||Ki-yu||Tsuchi-no-to Tori||Rooster, junior earth||47||庚戌||Koo-jutsu||Ka-no-e Inu||Dog, senior metal||48||辛亥||Shin-gai||Ka-no-to I||Pig, junior metal||49||壬子||Jin-shi||Mizu-no-e Ne||Rat, senior water||50||癸丑||Ki-chu||Mizu-no-to Ushi||Ox, junior water|
|51||甲寅||Koo-in||Ki-no-e Tora||Tiger, senior wood||52||乙卯||Itsu-bo||Ki-no-to U||Rabbit, junior wood||53||丙辰||Hei-shin||Hi-no-e Tatsu||Dragon, senior fire||54||丁巳||Tei-shi||Hi-no-to Mi||Snake, junior fire||55||戊午||Bo-go||Tsuchi-no-e Uma||Horse, senior earth|
|56||己未||Ki-bi||Tsuchi-no-to Hitsuji||Goat, junior earth||57||庚申||Koo-shin||Ka-no-e Saru||Monkey, senior metal||58||辛酉||Shin-yu||Ka-no-to Tori||Rooster, junior metal||59||壬戌||Jin-jutsu||Mizu-no-e Inu||Dog, senior water||60||癸亥||Ki-gai||Mizu-no-to I||Pig, junior water|
see each year page from Year table page.
Other calendar systems
Lunisolar calendar system in China
Lunisolar calendar system used in premodern Japan, was actually imported from China, supposed in 6th or 7th century. In China, lunisolar calendar system was used until 1911 officially, and still alive unofficially.
Lunisolar calendar methodology between in China and in Japan, were almost same. However, lunisolar system can create timezone difference based on the observation point. For example, think that new moon (Earth - Moon - Sun in column) was observed on 0.30am of a day in Japan (Kyoto), even in China (Beijing), it should be observed same time. But according to the timezone difference, new moon occur on 11.30pm of the previous day in China. It cause lunar month starts in different day between in China and Japan.
Please note that lunisolar calendar date can be different between China and Japan. Even within China, separated administration could cause multiple expression of date.
3 standard of January
There are 3 standard how to put January in the year.
- Zhou standard 周正. January was put on month of Rat 子, the lunar month includes winter solstice.
- Yin standard 殷正. January was put on month of Ox 丑, the next (except leap month) of Rat in lunar month (ie. winter solstice is in December).
- Xia standard 夏正. January was put on month of Tiger 寅, following month of Ox (ie. winter solstice is in November). Usually this is used as de-facto standard.
Islamic calendar (IC) system is pure lunar calendar, Islamic year is much shorter than solar year, new year can come in Winter, or in Summer by year. It was rarely used in (both premodern and modern) Japan, but recently become a little more popular.
|month of year||name||length|
|3rd month||Rabi al-awwal||30|
|4th month||Rabi al-thani||29|
|5th month||Jumada al-awwal||30|
|6th month||Jumada al-Thani||29|
|11th month||Dhu al-Qadah||30|
|12th month||Dhu al-Hijjah||29 / 30 in leap year|
- Julian day (JDN Julian Day Number) is the integer number of continuous days started 1 Jan 4713BC in Julian calendar.
- Julian date (JD) expresses the time which started 12.00UTC (noon) in the day 1 Jan 4713BC in Julian calendar, by unit day with fraction. JDN for 1 Jan 2017 is 2457755, so the 12.31.19JST (UTC+9H), 1 Jan 2017 will be expressed as:
- 2457755 + (12-9)/24 + 31/(24*60) + 19/(24*60*60) - 0.5 = 2457754.646747686