Japanese calendar types have included a range of official and unofficial systems. At present, Japan uses the Gregorian calendar together with year designations stating the year of the reign of the current Emperor. The written form starts with the year, then the month and finally the day, coinciding with the ISO 8601 standard. For example, February 16, 2003 can be written as either 2003年2月16日 or 平成15年2月16日 (the latter following the regnal year system). 年 reads nen and means "year", 月 reads gatsu or 「がつ」and means "month" and finally 日 (usually) reads nichi (its pronunciation depends on the number that precedes it, see below) and means "day".
Prior to the introduction of the Gregorian calendar in 1873, the reference calendar was based on the lunisolar Chinese calendar.
The lunisolar Chinese calendar was introduced to Japan via Korea in the middle of the sixth century. After that, Japan calculated its calendar using various Chinese calendar procedures, and from 1685, using Japanese variations of the Chinese procedures. But in 1873, as part of Japan's Meiji period modernization, a calendar based on the solar Gregorian calendar was introduced. In Japan today, the old Chinese calendar is virtually ignored; celebrations of the Lunar New Year are thus limited to Chinese and other Asian immigrant communities.
Japan has had more than one system for designating years:
"Kōki" redirects here. For the given name, see Kōki (given name).
The official dating system known as nengō (年号) (or, strictly speaking, gengō (元号)), has been in use since the late 7th century. Years are numbered within regnal eras, which are named by the reigning Emperor. Beginning with Meiji (1868–1912), each reign has been one era, but many earlier Emperors decreed a new era upon any major event; the last pre-Meiji Emperor's reign (1846–1867) was split into seven eras, one of which lasted only one year. The nengō system remains in wide use, especially on official documents and government forms.
The imperial year system (kōki) was used from 1872 to the Second World War. Imperial year 1 (Kōki 1) was the year when the legendary Emperor Jimmu founded Japan – 660 BC according to the Gregorian Calendar. Usage of kōki dating can be a nationalist signal, pointing out that the history of Japan's imperial family is longer than that of Christianity, the basis of the Anno Domini (AD) system. Kōki 2600 (1940) was a special year. The 1940 Summer Olympics and Tokyo Expo were planned as anniversary events, but were canceled due to the Second Sino-Japanese War. The Japanese naval Zero Fighter was named after this year. After the Second World War, the United States occupied Japan, and stopped the use of kōki by officials. Today, kōki is rarely used, except in some judicial contexts.
The 1898 law determining the placement of leap years is officially based on the kōki years, using a formula that is effectively equivalent to that of the Gregorian calendar: if the kōki year number is evenly divisible by four, it is a leap year, unless the number minus 660 is evenly divisible by 100 and not by 400. Thus, for example, the year Kōki 2560 (AD 1900) is divisible by 4; but 2560 − 660 = 1900, which is evenly divisible by 100 and not by 400, so kōki 2560 was not a leap year, just as in most of the rest of the world.
The present era, Reiwa, formally began on 1 May 2019. The name of the new era was announced by the Japanese government on 1 April 2019, a month prior to Naruhito's succession to the throne. The previous era, Heisei, came to an end on 30 April 2019, after Japan's former emperor, Akihito, abdicated the throne. Reiwa is the first era name whose characters come from a Japanese root source; prior eras' names were taken from Chinese classic literature.
|English name||Japanese name||Romanisation||Traditional dates|
|Spring||春||haru||February 5 – May 6|
|Summer||夏||natsu||May 7 – August 8|
|Autumn||秋||aki||August 9 – November 7|
|Winter||冬||fuyu||November 8 – February 4|
See also "Seasonal days", below.
The modern Japanese names for the months literally translate to "first month", "second month", and so on. The corresponding number is combined with the suffix 月 (-gatsu, "month"). The table below uses traditional numerals, but the use of Western numerals (１月, ２月, ３月 etc.) is common.
In addition, every month has a traditional name, still used by some in fields such as poetry; of the twelve, Shiwasu is still widely used today. The opening paragraph of a letter or the greeting in a speech might borrow one of these names to convey a sense of the season. Some, such as Yayoi and Satsuki, do double duty as given names (for women). These month names also appear from time to time on jidaigeki, contemporary television shows and movies set in the Edo period or earlier.
The old Japanese calendar was an adjusted lunar calendar based on the Chinese calendar, and the year—and with it the months—started anywhere from about 3 to 7 weeks later than the modern year, so in historical contexts it is not entirely accurate to equate the first month with January.
|English name||Common Japanese name||Traditional Japanese name|
|January||一月 (ichigatsu)||Mutsuki (睦月, "Month of Love," alternatively "Month of Affection").|
|February||二月 (nigatsu)||Kisaragi (如月) or Kinusaragi (衣更着, "Changing Clothes").|
|March||三月 (sangatsu)||Yayoi (弥生, "New Life").|
|April||四月 (shigatsu)||Uzuki (卯月, "u-no-hana month"). The u-no-hana (卯の花) is a flower, of the genus Deutzia.|
|May||五月 (gogatsu)||Satsuki (皐月) or Sanaetsuki (早苗月, "Early-rice-planting Month").|
|June||六月 (rokugatsu)||Minazuki (水無月, "Month of Water"). The 無 character, which normally means "absent" or "there is no", is ateji here, and is only used for the na sound. In this name the na is actually a possessive particle, so minazuki means "month of water", not "month without water", and this is in reference to the flooding of the rice fields, which require large quantities of water.|
|July||七月 (shichigatsu)||Fumizuki (文月, "Month of Erudition").|
|August||八月 (hachigatsu)||Hazuki (葉月, "Month of Leaves"). In old Japanese, the month was called 葉落ち月 (Haochizuki, or "Month of Falling Leaves").|
|September||九月 (kugatsu)||Nagatsuki (長月, "The Long Month").|
|October||十月 (jūgatsu)||Kannazuki or Kaminazuki (神無月, Month of the Gods). The 無 character, which normally means "absent" or "there is not", was here probably originally used as an ateji for the possessive particle na, so Kaminazuki may have originally meant "Month of the Gods", not "Month without Gods" (Kaminakizuki), similarly to Minatsuki, the "Month of Water". However, by what may be false etymology, the name became commonly interpreted to mean that, because in that month all the Shinto kami gather at Izumo shrine in Izumo Province (modern-day Shimane Prefecture), there are no gods in the rest of the country. Thus in Izumo Province, the month is called Kamiarizuki (神有月 or 神在月, "Month with Gods").  Various other etymologies have also been suggested from time to time.|
|November||十一月 (jūichigatsu)||Shimotsuki (霜月, "Month of Frost").|
|December||十二月 (jūnigatsu)||Shiwasu (師走, "Priests Running"). This is in reference to priests being busy at the end of the year for New Year's preparations and blessings.|
Japan uses a seven-day week, aligned with the Western calendar. The seven-day week, with names for the days corresponding to the Latin system, was brought to Japan around AD 800 with the Buddhist calendar. The system was used for astrological purposes and little else until 1876.
Much like in multiple European languages, in which the names for weekdays are, partially or fully, based on what the Ancient Romans considered the seven visible planets, meaning the five visible planets and the sun and the moon, in The Far East the five visible planets are named after the five Chinese elements (metal, wood, water, fire, earth.) On the origin of the names of the days of the week, also see East Asian Seven Luminaries.
|Japanese||Romanization||Element (planet)||English name|
* For those wondering, the Sun is 太陽 (great yang) and the Moon is 太陰 (great yin)
Sunday and Saturday are regarded as "Western style take-a-rest days". Since the late 19th century, Sunday has been regarded as a "full-time holiday", and Saturday a half-time holiday (半ドン). These holidays have no religious meaning (except those who believe in Christianity or Judaism). Many Japanese retailers do not close on Saturdays or Sundays, because many office workers and their families are expected to visit the shops during the weekend. An old Imperial Japanese Navy song (月月火水木金金) says "Mon Mon Tue Wed Thu Fri Fri!" which means "We work throughout the entire week."
Japanese people also use 10-day periods called jun (旬). Each month is divided into two 10-day periods and a third with the remaining 8 to 11 days:
These are frequently used to indicate approximate times, for example, "the temperatures are typical of the jōjun of April"; "a vote on a bill is expected during the gejun of this month." The magazine Kinema Junpo was originally published once every jun (i.e. three times a month).
Each day of the month has a semi-systematic name. The days generally use kun (native Japanese) numeral readings up to ten, and thereafter on (Chinese-derived) readings, but there are some irregularities. The table below shows dates written with traditional numerals, but use of Arabic numerals (１日, ２日, ３日, etc.) is extremely common in everyday communication, almost the norm.
Tsuitachi is a worn-down form of tsuki-tachi (月立ち), which means "the month beginning". The last day of the month was called tsugomori, which means "Moon hidden". This classical word comes from the tradition of the lunisolar calendar.
The 30th was also called misoka, just as the 20th is called hatsuka. Nowadays, the terms for the numbers 28–31 plus nichi are much more common. However, misoka is much used in contracts, etc., specifying that a payment should be made on or by the last day of the month, whatever the number is. New Year's Eve is known as Ōmisoka (大晦日, big 30th), and that term is still in use.
There is traditional belief that some days are lucky (kichijitsu) or unlucky. For example, there are some who will avoid beginning something on an unlucky day.
Main article: Holidays of Japan
After World War II, the names of Japanese national holidays were completely changed because of the secular state principle (Article 20, The Constitution of Japan). Although many of them actually originated from Shinto, Buddhism and important events relating to the Japanese imperial family, it is not easy to understand the original meanings from the superficial and vague official names.
Notes: Single days between two national holidays are taken as a bank holiday. This applies to May 4, which is a holiday each year. When a national holiday falls on a Sunday the next day that is not a holiday (usually a Monday) is taken as a holiday.
|Date||English name||Official name||Romanization|
|January 1||New Year's Day||元日||Ganjitsu|
|Second Monday of January||Coming of Age Day||成人の日||Seijin no hi|
|February 11||National Foundation Day†||建国記念の日||Kenkoku kinen no hi|
|February 23||The Emperor's Birthday||天皇誕生日||Tennō tanjōbi|
|March 20 or 21||Vernal Equinox Day||春分の日||Shunbun no hi|
|April 29||Shōwa Day*||昭和の日||Shōwa no hi|
|May 3||Constitution Memorial Day*||憲法記念日||Kenpō kinenbi|
|May 4||Greenery Day*||みどり(緑)の日||Midori no hi|
|May 5||Children's Day*||子供の日||Kodomo no hi|
|Third Monday of July||Marine Day||海の日||Umi no hi|
|August 11||Mountain Day||山の日||Yama no hi|
|Third Monday of September||Respect for the Aged Day||敬老の日||Keirō no hi|
|September 22 or 23||Autumnal Equinox Day||秋分の日||Shūbun no hi|
|Second Monday of October||Health and Sports Day||体育の日||Taiiku no hi|
|November 3||Culture Day||文化の日||Bunka no hi|
|November 23||Labour Thanksgiving Day||勤労感謝の日||Kinrō kansha no hi|
In contrast to other East Asian countries such as China, Vietnam, Korea and Mongolia, Japan has almost completely forgotten the Chinese calendar. Since 1876, January has been officially regarded as the "first month" even when setting the date of Japanese traditional folklore events (other months are the same: February as the second month, March as the third, and so on). But this system often brings a strong seasonal sense of gap since the event is 3 to 7 weeks earlier than in the traditional calendar. Modern Japanese culture has invented a kind of "compromised" way of setting dates for festivals called Tsuki-okure ("One-Month Delay") or Chūreki ("The Eclectic Calendar"). The festival is celebrated just one solar calendar month later than the date on the Gregorian calendar. For example, the Buddhist festival of Obon was the 15th day of the 7th month. Many places the religious services are held on July 15. However, in some areas, the rites are normally held on August 15, which is more seasonally close to the old calendar. (The general term "Obon holiday" always refers to the middle of August.) Although this is just de facto and customary, it is broadly used when setting the dates of many folklore events and religious festivals. But Japanese New Year is the great exception. The date of Japanese New Year is always January 1.
Some days have special names to mark the change in seasons. The 24 sekki (Japanese: 二十四節気; rōmaji: nijūshi sekki) are days that divide the solar year into twenty four equal sections. Zassetsu (雑節) is a collective term for the seasonal days other than the 24 sekki. 72 Kō (七十二候, Shichijūni kō) days are made from dividing the 24 sekki of a year further by three. These were named based upon the climate of Northern China, so many of the names do not fit in with the climate of Japanese archipelago. But some of these names, such as Shunbun, Risshū and Tōji, are still used quite frequently in everyday life in Japan.
Dates can vary by one day either way.
|February 3||節分||Setsubun||The eve of Risshun by one definition.|
|March 18–March 24||春彼岸||Haru higan||The seven days surrounding Shunbun.|
|Vernal Equinox day||春社日||Haru shanichi||In Shinto. 彼岸中日 (Higan Chunichi) in Buddhism.|
|May 2||八十八夜||Hachijū hachiya||Literally meaning 88 nights (since Risshun).|
|June 11||入梅||Nyūbai||Literally meaning entering tsuyu.|
|July 2||半夏生||Hangeshō||One of the 72 Kō. Farmers take five days off in some regions.|
|July 15||中元||Chūgen||Officially July 15. August 15 in many regions (Tsuki-okure).|
|July 20||夏の土用||Natsu no doyō||Custom of eating eel on this day.|
|September 1||二百十日||Nihyaku tōka||Literally meaning 210 days (since Risshun).|
|September 11||二百二十日||Nihyaku hatsuka||Literally meaning 220 days.|
|September 20–September 26||秋彼岸||Aki higan|
|Autumal Equinox||秋社日||Aki shanichi||In Shinto. 彼岸中日 in Buddhism.|
Shanichi dates can vary by as much as 5 days. Chūgen has a fixed day. All other days can vary by one day.
Many zassetsu days occur in multiple seasons:
The following are known as the five seasonal festivals (節句 sekku, also 五節句 gosekku). The sekku were made official holidays during Edo period on Chinese lunisolar calendar. The dates of these festivals are confused nowadays; some on the Gregorian calendar, others on "Tsuki-okure".
The rokuyō (六曜) are a series of six days calculated from the date of Chinese calendar that supposedly predict whether there will be good or bad fortune during that day. The rokuyō are commonly found on Japanese calendars and are often used to plan weddings and funerals, though most people ignore them in ordinary life. The rokuyō are also known as the rokki (六輝). In order, they are:
|先勝||Senshō||Good luck before noon, bad luck after noon. Good day for beginnings (in the morning).|
|友引||Tomobiki||Your friends may be "drawn-in" towards good and evil. Funerals are avoided on this day (tomo = friend, biki = pull, thus a funeral might pull friends toward the deceased). Typically crematoriums are closed this day. But, for instance, weddings are fine on this day.|
|先負||Senbu||Bad luck before noon, good luck after noon.|
|仏滅||Butsumetsu||Symbolizes the day Buddha died. Considered the most unlucky day. Weddings are best avoided. Some Shinto shrines close their offices on this day.|
|大安||Taian||The most lucky day. Good day for weddings and events like shop openings.|
|赤口||Shakkō||The hour of the horse (11 am to 1 pm) is lucky. The rest is bad luck.|
The rokuyō days are easily calculated from the Japanese lunisolar calendar. The first day of the first month is always senshō, with the days following in the order given above until the end of the month. Thus, the 2nd day is tomobiki, the 3rd is senbu, and so on. The 1st day of the 2nd month restarts the sequence at tomobiki. The 3rd month restarts at senbu, and so on for each month. The latter six months repeat the patterns of the first six, so the 1st of the 7th is senshō, the 1st of the 12th is shakkō and the moon-viewing day on the 15th of the 8th is always butsumetsu.
This system did not become popular in Japan until the end of the Edo period.
The first day of April has broad significance in Japan. It marks the beginning of the government's fiscal year. Many corporations follow suit. In addition, corporations often form or merge on that date. In recent years, municipalities have preferred it for mergers. On this date, many new employees begin their jobs, and it is the start of many real-estate leases. The school year begins on April 1.