Every Chronology - Unit of time (Japanese calendar)

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 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.
== History ==
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:
* The Chinese sexagenary cycle was introduced early into Japan. It was often used together with era names, as in the 1729 Ise calendar shown above, which is for "the 14th year of Kyōhō, tsuchi-no-to no tori", i.e., 己酉. Now, though, the cycle is seldom used except around New Year.
* The era name (元号, gengō) system was also introduced from China, and has been in continuous use since AD 701. Since the Taishō Emperor's ascension in 1912, each emperor's reign has begun a new era; before 1868 era names were often also declared for other reasons. Nengō are the official means of dating years in Japan, and virtually all government business is conducted using that system. It is also in general use in private and personal business.
* The Japanese imperial year (皇紀, kōki, or 紀元 kigen) is based on the date of the legendary founding of Japan by Emperor Jimmu in 660 BC. It was first used in the official calendar in 1873. However, it never replaced era names, and since World War II has been abandoned.
* The Western Common Era (Anno Domini) (西暦, seireki) system has gradually come into common use since the Meiji period. Nowadays, Japanese people know it as well as the regnal eras.
* The era name (十年記, jūnenki) system was also introduced from Japan, and has been in continuous use since AD 2018.
== Second or Minutes ==
The second or minutes (symbol: s or m) is the unit of time in the International System of Units (SI), historically defined as 1⁄86400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each (24 × 60 × 60 = 86400).
* One minute (1分) - 60 seconds (60秒)
* One hour (1時間) - 60 minutes (60分) - 3,600 seconds (3,600秒)
* One day (1日) - 24 hours (24時間) - 1,440 minutes (1,440分) - 86,400 seconds (86,400秒)
== Official calendar ==
=== Years ===
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 governmenton 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.
==== Decades, Centuries, Millenniums ====
Although a century can mean any arbitrary period of 100 years, there are two viewpoints on the nature of standard centuries. One is based on strict construction, while the other is based on popular perception. 
According to the strict construction, the 1st century AD began with AD 1 and ended with AD 100, the 2nd century spanning the years 101 to 200, with the same pattern continuing onward. In this model, the n-th century starts with the year that ends with "01", and ends with the year that ends with "00"; for example, the 20th century comprises the years 1901 to 2000 in strict usage in Strict culture, constitute the 20th century. (This is similar to the grouping of "1-to-0 decades"which share the 'tens' digit.)
In popular perception and practice, centuries are structured by grouping years based on sharing the 'hundreds' digit(s). In this model, the n-th century starts with the year that ends in "00" and ends with the year ending in "99"; for example, the years 1900 to 1999, in popular culture, constitute the 20th century. (This is similar to the grouping of "0-to-9 decades"which share the 'tens' digit.)
Strict vs Popular usage (Every Year, Decade, Century and Millennium)
Year
(年)	Year 	2 BC 	1 BC 	1 	2 	3 	… 	99 	100 	101 	102 	103 	… 	199 	200 	201 	202 	…	1899 	1900 	1901 	1902 	… 	1999 	2000 	2001 	2002 	… 	2099 	2100 	2101 	2102 	…
Decade
(十年紀)	Strict 	1st decade BC 	1st decade BC 	1st decade 	1st decade 	1st decade 	… 	10th decade 	10th decade 	11th decade 	11th decade 	11th decade 	… 	20th decade 	20th decade 	21st decade 	21st decade 	…	190th decade 	190th decade 	191st decade 	191st decade 	… 	200th decade 	200th decade 	201st decade 	201st decade 	… 	210th decade 	210th decade 	211th decade 	211th decade 	…
Century
(世紀)	Strict 	1st century BC 	1st century BC 	1st century 	1st century 	1st century 	1st century 	1st century 	1st century 	2nd century 	2nd century 	2nd century 	2nd century 	2nd century 	2nd century 	3rd century 	3rd century 	…	19th century 	19th century 	20th century 	20th century 	20th century 	20th century 	20th century 	21st century 	21st century 	21st century 	21st century 	21st century 	22nd century 	22nd century 	…
Millennium
(千年紀)	Strict 	1st millennium BC	1st millennium BC	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	…	2nd millennium	2nd millennium	2nd millennium	2nd millennium	2nd millennium	2nd millennium	2nd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	…
Decade
(十年紀)	Popular	0s BC 	0s BC 	0s 	0s 	0s 	… 	90s 	100s 	100s 	100s 	100s 	… 	190s 	200s 	200s 	200s 	…	1890s 	1900s 	1900s 	1900s 	… 	1990s 	2000s 	2000s 	2000s 	… 	2090s 	2100s 	2100s 	2100s 	…
Century
(世紀)	Popular	1st century BC 	1st century BC 	1st century 	1st century 	1st century 	1st century 	1st century 	2nd century 	2nd century 	2nd century 	2nd century 	2nd century 	2nd century 	3rd century 	3rd century 	3rd century 	…	19th century 	20th century 	20th century 	20th century 	20th century 	20th century 	21st century 	21st century 	21st century 	21st century 	21st century 	22nd century 	22nd century 	22nd century 	…
Millennium
(千年紀)	Popular	1st millennium BC	1st millennium BC	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	1st millennium	…	2nd millennium	2nd millennium	2nd millennium	2nd millennium	2nd millennium	2nd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	3rd millennium	…
Usage methods compared (New Decades & Centuries)
Year 	1 	2 	3 	… 	9 	10 	11 	12 	… 	19 	20 	…	2000 	2001 	2002 	… 	2009 	2010 	2011 	2012 	… 	2019 	2020 	2021 	2022 	… 	2029 	2030
1-to-0 decade 	1st decade 	1st decade 	1st decade 	1st decade 	1st decade 	1st decade 	2nd decade 	2nd decade 	2nd decade 	2nd decade 	2nd decade 	…	200th decade	201st decade	201st decade	201st decade	201st decade	201st decade	202nd decade	202nd decade	202nd decade	202nd decade	202nd decade	203rd decade	203rd decade	203rd decade	203rd decade	203rd decade
0-to-9 decade 	0s 	0s 	0s 	0s 	0s 	10s 	10s 	10s 	10s 	10s 	10s 	…	2000s 	2000s 	2000s 	2000s 	2000s 	2010s 	2010s 	2010s 	2010s 	2010s 	2020s 	2020s 	2020s 	2020s 	2020s 	…
1-to-0 century	1st century	1st century	1st century	1st century	1st century	1st century	1st century	1st century	1st century	1st century	1st century	…	20th century	21st century	21st century	21st century	21st century	21st century	21st century	21st century	21st century	21st century	21st century	21st century	21st century	21st century	21st century	21st century
0-to-9 century	0s 	0s 	0s 	0s 	0s 	0s 	0s 	0s 	0s 	0s 	0s 	…	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s 	2000s
=== Seasons ===
English name 	Japanese name	Traditional dates 	Traditional dates
Winter 	冬 	December, January, February 	Sagittarius ♐️, Capricorn ♑️, Aquarius ♒️
Spring 	春 	March, April, May 	Pisces ♓️, Aries ♈️, Taurus ♉️
Summer 	夏 	June, July, August 	Gemini ♊️, Cancer ♋️, Leo ♌️
Autumn (Fall)	秋 	September, October, November	Virgo ♍️, Libra ♎️, Scorpio ♏️
=== Astrological of the Months ===
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	English name 	Common Japanese name	Common Japanese name	House	Polarity	Modality	Triplicity	Northern Hemisphere Season	Southern Hemisphere Season
January 	Capricorn ♑️ 	1月 	やぎ座 	1 	Negative	Cardinal	Earth 	Winter 	Summer
February 	Aquarius ♒️ 	2月 	みずがめ座 	2 	Positive	Fixed 	Air 	Winter 	Summer
March 	Pisces ♓️ 	3月 	うお座 	3 	Negative	Mutable 	Water 	Spring 	Autumn (Fall)
April 	Aries ♈️ 	4月 	おひつじ座 	4 	Positive	Cardinal	Fire 	Spring 	Autumn (Fall)
May 	Taurus ♉️ 	5月 	おうし座 	5 	Negative	Fixed 	Earth 	Spring 	Autumn (Fall)
June 	Gemini ♊️ 	6月 	ふたご座 	6 	Positive	Mutable 	Air 	Summer 	Winter
July 	Cancer ♋️ 	7月 	癌 	7 	Negative	Cardinal	Water 	Summer 	Winter
August 	Leo ♌️ 	8月 	しし座 	8 	Positive	Fixed 	Fire 	Summer 	Winter
September 	Virgo ♍️ 	9月 	おとめ座 	9 	Negative	Mutable 	Earth 	Autumn (Fall) 	Spring
October 	Libra ♎️ 	10月 	天秤宮 	10 	Positive	Cardinal	Air 	Autumn (Fall) 	Spring
November 	Scorpio ♏️ 	11月 	さそり座 	11 	Negative	Fixed 	Water 	Autumn (Fall) 	Spring
December 	Sagittarius ♐️	12月 	いて座 	12 	Positive	Mutable 	Fire 	Winter 	Summer
=== Subdivisions of the month ===
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.
English name	Japanese	Element (planet)
Sunday 	日曜日 	Sun
Monday 	月曜日 	Moon
Tuesday 	火曜日 	Fire (Mars)
Wednesday 	水曜日 	Water (Mercury)
Thursday 	木曜日 	Wood (Jupiter)
Friday 	金曜日 	Metal (Venus)
Saturday 	土曜日 	Earth (Saturn)
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:
* The first (from the 1st to the 10th) is jōjun (上旬, upper jun)
* The second (from the 11th to the 20th), chūjun (中旬, middle jun)
* The last (from the 21st to the end of the month), gejun (下旬, lower jun).
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).
=== Days of the 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.
Day number	Japanese name	Week number	Japanese name
1 	1日 	1 week 	1週間
2 	2日 	1 week 	1週間
3 	3日 	1 week 	1週間
4 	4日 	1 week 	1週間
5 	5日 	1 week 	1週間
6 	6日 	1 week 	1週間
7 	7日 	1 week 	1週間
8 	8日 	2 weeks 	2週間
9 	9日 	2 weeks 	2週間
10 	10日 	2 weeks 	2週間
11 	11日 	2 weeks 	2週間
12 	12日 	2 weeks 	2週間
13 	13日 	2 weeks 	2週間
14 	14日 	2 weeks 	2週間
15 	15日 	3 weeks 	3週間
16 	16日 	3 weeks 	3週間
17 	17日 	3 weeks 	3週間
18 	18日 	3 weeks 	3週間
19 	19日 	3 weeks 	3週間
20 	20日 	3 weeks 	3週間
21 	21日 	3 weeks 	3週間
22 	22日 	4 weeks 	4週間
23 	23日 	4 weeks 	4週間
24 	24日 	4 weeks 	4週間
25 	25日 	4 weeks 	4週間
26 	26日 	4 weeks 	4週間
27 	27日 	4 weeks 	4週間
28 	28日 	4 weeks 	4週間
29 	29日 	5 weeks 	5週間
30 	30日 	5 weeks 	5週間
31 	31日 	5 weeks 	5週間
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.
=== National holidays ===
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.
Japanese national holidays
* Capricorn ♑️ (January - 1月):
** January 1 - New Year Day's (元日)
** Second Monday of January - Coming of Age Day (成人の日)
** January 22 - The RobotDiamant's Birthday (ロボットディアマントの誕生日)
* Aquarius ♒️ (February - 2月):
** February 11 - National Foundation Day (建国記念の日)
** February 23 - The Emperor's Day (天皇誕生日)
* Pisces ♓️ (March - 3月):
** March 20 or 21 - Vernal Equinox Day (春分の日)
* Aries ♈️ (April - 4月):
** April 29 - Shōwa Day (昭和の日)
* Taurus ♉️ (May - 5月):
** May 2 - The RobotDiamant's Anniversary Day (ロボットディアマントの記念日)
** May 3 - Constitution Memorial Day (憲法記念日)
** May 4 - Greenery Day (みどり(緑)の日)
** May 5 - Children's Day (子供の日)
* Cancer ♋️ (July - 7月):
** Third Monday of July - Marine Day (海の日)
* Leo ♌️ (August - 8月):
** August 11 - Mountain Day (山の日)
* Virgo ♍️ (September - 9月):
** Third Monday of September - Respect for the Aged Day (敬老の日)
** September 22 or 23 - Autumnal Equinox Day (秋分の日)
* Libra ♎️ (October - 10月):
** Second Monday of October - Health and Sports Day (体育の日)
* Sagittarius ♐️ (November - 11月):
** November 3 - Culture Day (文化の日)
** November 23 - Labour Thanksgiving Day (勤労感謝の日)
* Traditional date on which according to legend Emperor Jimmu founded Japan in 660 BC (66th decade BC, 7th century BC, 1st millennium BC).
* Part of Golden Week.
Timeline of changes to national holidays:
* 2nd millennium:
** 20th century:
*** 195th decade:
**** 1948: The following national holidays were introduced: New Year's Day, Coming-of-Age Day, Constitution Memorial Day, Children's Day, Autumnal Equinox Day, Culture Day, Labour Thanksgiving Day.
*** 197th decade:
**** 1966: Health and Sports Day was introduced in memory of the 1964 Tokyo Olympics. Vernal Equinox Day was also introduced.
*** 199th decade:
**** 1985: Reform to the national holiday law made May 4, sandwiched between two other national holidays, also a holiday.
**** 1989: After the Shōwa Emperor died on January 7, the Emperor's Birthday became December 23 and Greenery Day took the place of the former Emperor's birthday.
* 2nd millennium & 3rd millennium:
** 20th & 21st century:
*** 200th & 201st decades:
**** 2000, 2003: Happy Monday System (ハッピーマンデー制度, Happī Mandē Seido) moved several holidays to Monday. Starting with 2000: Coming-of-Age Day (formerly January 15) and Health and Sports Day (formerly October 10). Starting with 2003: Marine Day (formerly July 20) and Respect for the Aged Day (formerly September 15).
**** 2005, 2007: According to a May 2005 decision, starting with 2007 Greenery Day will be moved from April 29 to May 4 replacing a generic national holiday (国民の休日, kokumin no kyūjitsu) that existed after the 1985 reform, while April 29 will be known as Shōwa Day.
**** 2009: September 22 may become sandwiched between two holidays, which would make this day a national holiday.
*** 202nd decade:
**** 2014: Mountain Day established as a new holiday, to be observed starting 2016
**** 2015: RobotDiamant established as a new holiday on New Japanese YTP, Memes.
**** 2019: Emperor's Birthday not celebrated. The final celebration of Emperor's Birthday during the Heisei era took place on December 23, 2018, the birthday of Akihito. After the start of the Reiwa era on 1 May 2019, the next celebration of Emperor's Birthday is expected to take place on or around 23 February 2020, the birthday of the reigning Emperor Naruhito (as Naruhito's birthday falls on a Sunday in 2020, the official public holiday is expected to be celebrated on Monday, 24 February 2020 instead).
== List of Japanese era names ==
To convert a Japanese year to a Gregorian calendar year, find the first year of the Japanese era name (also called nengō). When found, add the number of the Japanese year, then subtract 1.
* Asuka period (飛鳥時代)
** 1st millennium AD
*** 7th century AD
**** 65th decade AD
**** Taika - 大化 (645–650 AD)
**** 66th decade AD
**** Hakuchi - 白雉 (650–654 AD)
**** 69th decade AD
**** Shuchō - 朱鳥 (686 AD)
*** 8th century AD
**** 71st decade AD
**** Taihō - 大宝 (701–704 AD)
**** Keiun - 慶雲 (704-708 AD)
****Wadō - 和銅 (708–715 AD)
****72nd decade AD
*Nara period (奈良時代)
**8th century AD
***72nd decade AD
***Reiki - 霊亀 (715–717 AD)
***Yōrō - 養老 (717-724 AD)
***73rd decade AD
***Jinki - 神亀 (724-729 AD)
***Tenpyō - 天平 (729–749 AD)
***74th decade AD
***75th decade AD
***Tenpyō-kanpō - 天平感宝 (749 AD)
***Tenpyō-shōhō - 天平勝宝 (749-757 AD)
***76th decade AD
***Tenpyō-hōji - 天平宝字 (757-765 AD)
***77th decade AD
***Tenpyō-jingo - 天平神護 (765–767 AD)
***Jingo-keiun - 神護景雲 (767–770 AD)
***Hōki - 宝亀 (770–781 AD)
***78th decade AD
***79th decade AD
***Ten'ō - 天応 (781-782 AD)
***Enryaku - 延暦 (782–806 AD)
***80th decade AD
**9th century AD
***81st decade AD
*Heian period (平安時代)
**9th century AD
***81st decade AD
***Daidō - 大同 (806–810 AD)
***Kōnin - 弘仁 (810–824 AD)
***82nd decade AD
***83rd decade AD
***Tenchō - 天長 (824–834 AD)
***84th decade AD
***Jōwa - 承和 (834–848 AD)
***85th decade AD
***Kashō - 嘉祥 (848-851 AD)
***86th decade AD
***Ninju - 仁寿 (851-854 AD)
***Saikō - 斉衡 (854–857 AD)
***Ten'an - 天安 (857–859 AD)
***Jōgan - 貞観 (859–877 AD)
***87th decade AD
***88th decade AD
***Gangyō - 元慶 (877–885 AD)
***89th decade AD
***Ninna - 仁和 (885–889 AD)
***Kanpyō - 寛平 (889–898 AD)
***90th decade AD
***Shōtai - 昌泰 (898-901 AD)
**10th century AD
***91st decade AD
***Engi - 延喜 (901–923 AD)
***92nd decade AD
***93rd decade AD
***Enchō - 延長 (923–931 AD)
***94th decade AD
***Jōhei - 承平 (931–938 AD)
***Tengyō - 天慶 (938–947 AD)
***95th decade AD
***Tenryaku - 天暦 (947–957 AD)
***96th decade AD
***Tentoku - 天徳 (957–961 AD)
***97th decade AD
***Ōwa - 応和 (961–964 AD)
***Kōhō - 康保 (964–968 AD)
***Anna - 安和 (968–970 AD)
***Tenroku - 天禄 (970–974 AD)
***98th decade AD
***Ten'en - 天延 (974–976 AD)
***Jōgen - 貞元 (976–978 AD)
***Tengen - 天元 (978-983 AD)
***99th decade AD
***Eikan - 永観 (983–985 AD)
***Kanna - 寛和 (985–987 AD)
***Eien - 永延 (987–989 AD)
***Eiso - 永祚 (989–990 AD)
***Shōryaku - 正暦 (990–995 AD)
***100th decade AD
***Chōtoku - 長徳 (995–999 AD)
***Chōhō - 長保 (999-1004 AD)
*2nd millennium AD
**11th century AD
***101st decade AD
***Kankō - 寛弘 (1004–1012 AD)
***102nd decade AD
***Chōwa - 長和 (1012–1017 AD)
***Kannin - 寛仁 (1017–1021 AD)
***103rd decade AD
***Jian - 治安 (1021–1024 AD)
***Manju - 万寿 (1024–1028 AD)
***Chōgen - 長元 (1028-1037 AD)
***104th decade AD
***Chōryaku - 長暦 (1037–1040 AD)
***Chōkyū - 長久 (1040–1044 AD)
***105th decade AD
***Kantoku - 寛徳 (1044–1046 AD)
***Eishō - 永承 (1046–1053 AD)
***106th decade AD
***Tengi - 天喜 (1053–1058 AD)
***Kōhei - 康平 (1058–1065 AD)
***107th decade AD
***Jiryaku - 治暦 (1065–1069 AD)
***Enkyū - 延久 (1069–1074 AD)
***108th decade AD
***Jōhō - 承保 (1074–1077 AD)
***Jōryaku - 承暦 (1077–1081 AD)
***109th decade AD
***Eihō - 永保 (1081–1084 AD)
***Ōtoku - 応徳 (1084–1087 AD)
***Kanji - 寛治 (1087–1094 AD)
***110th decade AD
***Kahō - 嘉保 (1094–1096 AD)
***Eichō - 永長 (1096–1097 AD)
***Jōtoku - 承徳 (1097–1099 AD)
***Kōwa - 康和 (1099–1104 AD)
**12th century AD
***111th decade AD
***Chōji - 長治 (1104–1106 AD)
***Kajō - 嘉承 (1106–1108 AD)
***Tennin - 天仁 (1108–1110 AD)
***Ten'ei - 天永 (1110–1113 AD)
***112th decade AD
***Eikyū - 永久 (1113–1118 AD)
***Gen'ei - 元永 (1118–1120 AD)
***Hōan - 保安 (1120–1124 AD)
***113th decade AD
***Tenji - 天治 (1124–1126 AD)
***Daiji - 大治 (1126–1131 AD)
***114th decade AD
***Tenshō - 天承 (1131–1132 AD)
***Chōshō - 長承 (1132–1135 AD)
***Hōen - 保延 (1135–1141 AD)
***115th decade AD
***Eiji - 永治 (1141–1142 AD)
***Kōji - 康治 (1142–1144 AD)
***Ten'yō - 天養 (1144–1145 AD)
***Kyūan - 久安 (1145–1151 AD)
***116th decade AD
***Ninpei - 仁平 (1151–1154 AD)
***Kyūju - 久寿 (1154-1156 AD)
***Hōgen - 保元 (1156–1159 AD)
***Heiji - 平治 (1159–1160 AD)
***Eiryaku - 永暦 (1160–1161 AD)
***117th decade AD
***Ōhō - 応保 (1161–1163 AD)
***Chōkan - 長寛 (1163–1165 AD)
***Eiman - 永万 (1165–1166 AD)
***Nin'an - 仁安 (1166–1169 AD)
***Kaō - 嘉応 (1169–1171 AD)
***118th decade AD
***Jōan - 承安 (1171–1175 AD)
***Angen - 安元 (1175–1177 AD)
***Jishō - 治承 (1177–1181 AD)
***119th decade AD
***Yōwa - 養和 (1181-1182 AD)
***Juei - 寿永 (1182–1185 AD)
***Juei - 寿永 (1183–1184 AD)
***Genryaku - 元暦 (1184–1185 AD)
*Kamakura period (鎌倉時代)
**12th century AD
***119th decade AD
***Bunji - 文治 (1185-1190 AD)
***Kenkyū - 建久 (1190–1199 AD)
***120th decade AD
***Shōji - 正治 (1199–1201 AD)
**13th century AD
***121st decade AD
***Kennin - 建仁 (1201–1204 AD)
***Genkyū - 元久 (1204-1206 AD)
***Ken'ei - 建永 (1206–1207 AD)
***Jōgen - 承元 (1207–1211 AD)
***122nd decade AD
***Kenryaku - 建暦 (1211–1213 AD)
***Kempo - 建保 (1213–1219 AD)
***Jōkyū - 承久 (1219–1222 AD)
***123rd decade AD
***Jōō - 貞応 (1222–1224 AD)
***Gennin - 元仁 (1224–1225 AD)
***Karoku - 嘉禄 (1225–1227 AD)
***Antei - 安貞 (1227–1229 AD)
***Kangi - 寛喜 (1229–1232 AD)
***124th decade AD
***Jōei - 貞永 (1232–1233 AD)
***Tenpuku - 天福 (1233–1234 AD)
***Bunryaku - 文暦 (1234–1235 AD)
***Katei - 嘉禎 (1235–1238 AD)
***Ryakunin - 暦仁 (1238–1239 AD)
***En'ō - 延応 (1239–1240 AD)
***Ninji - 仁治 (1240–1243 AD)
***125th decade AD
***Kangen - 寛元 (1243–1247 AD)
***Hōji - 宝治 (1247–1249 AD)
***Kenchō - 建長 (1249–1256 AD)
***126th decade AD
***Kōgen - 康元 (1256–1257 AD)
***Shōka - 正嘉 (1257–1259 AD)
***Shōgen - 正元 (1259–1260 AD)
***Bun'ō - 文応 (1260–1261 AD)
***127th decade AD
***Kōchō - 弘長 (1261–1264 AD)
***Bun'ei - 文永 (1264–1275 AD)
***128th decade AD
***Kenji - 建治 (1275–1278 AD)
***Kōan - 弘安 (1278–1288 AD)
***129th decade AD
***Shōō - 正応 (1288–1293 AD)
***130th decade AD
***Einin - 永仁 (1293–1299 AD)
***Shōan - 正安 (1299–1302 AD)
**14th century AD
***131st decade AD
***Kengen - 乾元 (1302–1303 AD)
***Kagen - 嘉元 (1303–1306 AD)
***Tokuji - 徳治 (1306–1308 AD)
***Enkyō - 延慶 (1308–1311 AD)
***132nd decade AD
***Ōchō - 応長 (1311–1312 AD)
***Shōwa - 正和 (1312–1317 AD)
***Bunpō - 文保 (1317–1319 AD)
***Gen'ō - 元応 (1319–1321 AD)
***133rd decade AD
***Genkō - 元亨 (1321–1324 AD)
***Shōchū - 正中 (1324–1326 AD)
***Karyaku - 嘉暦 (1326–1329 AD)
***Gentoku - 元徳 (1329–1332 AD)
***134th decade AD
***Genkō - 元弘 (1331–1334 AD)
*Nanboku-chō period (南北町時代)
**14th century AD
***134th decade AD
***Shōkyō - 正慶 (1332–1333 AD)
***Kenmu - 建武 (1334–1336 AD)
***Engen - 延元 (1336–1340 AD)
***Kōkoku - 興国 (1340–1347 AD)
***Kenmu - 建武 (1336–1338 AD)
***Ryakuō - 暦応 (1338–1342 AD)
***135th decade AD
***Kōei - 康永 (1342-1345 AD)
***Jōwa - 貞和 (1345–1350 AD)
***Kannō - 観応 (1350–1352 AD)
***Shōhei - 正平 (1347–1370 AD)
***136th decade AD
***Bunna - 文和 (1352–1356 AD)
***Enbun - 延文 (1356–1361 AD)
***137th decade AD
***Kōan - 康安 (1361–1362 AD)
***Jōji - 貞治 (1362–1368 AD)
***Ōan - 応安 (1368–1375 AD)
***Kentoku - 建徳 (1370–1372 AD)
***138th decade AD
***Bunchū - 文中 (1372–1375 AD)
***Eiwa - 永和 (1375–1379 AD)
***Tenju - 天授 (1375–1381 AD)
***Kōryaku - 康暦 (1379–1381 AD)
***139th decade AD
***Eitoku - 永徳 (1381–1384 AD)
***Kōwa - 弘和 (1381–1384 AD)
***Genchū - 元中 (1384–1392 AD)
***Shitoku - 至徳 (1384–1387 AD)
***Kakei - 嘉慶 (1387–1389 AD)
***Kōō - 康応 (1389–1390 AD)
***Meitoku - 明徳 (1390–1394 AD)
*Muromachi period (室町時代)
**14th century AD
***140th decade AD
***Ōei - 応永 (1394–1428 AD)
**15th century AD
***141st decade AD
***142nd decade AD
***143rd decade AD
***Shōchō - 正長 (1428–1429 AD)
***Eikyō - 永享 (1429–1441 AD)
***144th decade AD
***145th decade AD
***Kakitsu - 嘉吉 (1441–1444 AD)
***Bun'an - 文安 (1444–1449 AD)
***Hōtoku - 宝徳 (1449–1452 AD)
***146th decade AD
***Kyōtoku - 享徳 (1452–1455 AD)
***Kōshō - 康正 (1455–1457 AD)
***Chōroku - 長禄 (1457–1460 AD)
***Kanshō - 寛正 (1460–1466 AD)
***147th decade AD
***Bunshō - 文正 (1466–1467 AD)
***Ōnin - 応仁 (1467–1469 AD)
***Bunmei - 文明 (1469–1487 AD)
***148th decade AD
***149th decade AD
***Chōkyō - 長享 (1487–1489 AD)
***Entoku - 延徳 (1489–1492 AD)
***150th decade AD
***Meiō - 明応 (1492–1501 AD)
**16th century AD
***151st decade AD
***Bunki - 文亀 (1501–1504 AD)
***Eishō - 永正 (1504–1521 AD)
***152nd decade AD
***153rd decade AD
***Daiei - 大永 (1521–1528 AD)
***Kyōroku - 享禄 (1528–1532 AD)
***154th decade AD
***Tenbun - 天文 (1532–1555 AD)
***155th decade AD
***156th decade AD
***Kōji - 弘治 (1555–1558 AD)
***Eiroku - 永禄 (1558–1570 AD)
***157th decade AD
***Genki - 元亀 (1570–1573 AD)
*Azuchi–Momoyama period (安土桃山時代)
**16th century AD
***158th decade AD
***Tenshō - 天正 (1573–1592 AD)
***159th decade AD
***160th decade AD
***Bunroku - 文禄 (1592–1596 AD)
***Keichō - 慶長 (1596–1615 AD)
*Edo period (江戸時代)
**17th century AD
***161st decade AD
***162nd decade AD
***Genna - 元和 (1615–1624 AD)
***163rd decade AD
***Kan'ei - 寛永 (1624–1644 AD)
***164th decade AD
***165th decade AD
***Shōhō - 正保 (1645–1648 AD)
***Keian - 慶安 (1648–1652 AD)
***166th decade AD
***Jōō - 承応 (1652–1655 AD)
***Meireki - 明暦 (1655–1658 AD)
***Manji - 万治 (1658–1661 AD)
***167th decade AD
***Kanbun - 寛文 (1661–1673 AD)
***168th decade AD
***Enpō - 延宝 (1673–1681 AD)
***169th decade AD
***Tenna - 天和 (1681–1684 AD)
***Jōkyō - 貞享 (1684–1688 AD)
***Genroku - 元禄 (1688–1704 AD)
***170th decade AD
**18th century AD
***171st decade AD
***Hōei - 宝永 (1704–1711 AD)
***172nd decade AD
***Shōtoku - 正徳 (1711–1716 AD)
***Kyōhō - 享保 (1716-1736 AD)
***173rd decade AD
***174th decade AD
***Genbun - 元文 (1736–1741 AD)
***175th decade AD
***Kanpō - 寛保 (1741–1744 AD)
***Enkyō - 延享 (1744–1748 AD)
***Kan'en - 寛延 (1748–1751 AD)
***176th decade AD
***Hōreki - 宝暦 (1751–1764 AD)
***177th decade AD
***Meiwa - 明和 (1764–1772 AD)
***178th decade AD
***An'ei - 安永 (1772–1781 AD)
***179th decade AD
***Tenmei - 天明 (1781–1789 AD)
***Kansei - 寛政 (1789–1801 AD)
***180th decade AD
**19th century AD
***181st decade AD
***Kyōwa - 享和 (1801–1804 AD)
***Bunka - 文化 (1804–1818 AD)
***182nd decade AD
***Bunsei - 文政 (1818–1830 AD)
***183rd decade AD
***Tenpō - 天保 (1830–1844 AD)
***184th decade AD
***185th decade AD
***Kōka - 弘化 (1844–1848 AD)
***Kaei - 嘉永 (1848–1854 AD)
***186th decade AD
***Ansei - 安政 (1854–1860 AD)
***Man'en 万延 (1860–1861 AD)
***187th decade AD
***Bunkyū - 文久 (1861–1864 AD)
***Genji - 元治 (1864–1865 AD)
***Keiō - 慶応 (1865–1868 AD)
*Modern Japan (現代日本)
**19th century AD
***187th decade AD
***Meiji - 明治 (1868–1912 AD)
***188th decade AD
***189th decade AD
***190th decade AD
***191st decade AD
***192nd decade AD
***Taishō - 大正 (1912–1926 AD)
***193rd decade AD
***Shōwa - 昭和 (1926–1989 AD)
***194th decade AD
***195th decade AD
***196th decade AD
***197th decade AD
***198th decade AD
***199th decade AD
***Heisei - 平成 (1989–2019 AD)
***200th decade AD
*3rd millennium AD
**21st century AD
***201st decade AD
***202nd decade AD
***Reiwa - 令和 (2019 AD—present)
***203rd decade AD (current decade)
=== Non-nengō periods ===
Unofficial non-nengō periods (shinengō) before 701 are called itsunengō (逸年号). Pre-Taika chronology intervals include:
* 1st millennium BC 
** 7th century BC
*** 66th decade BC
*** Reign of Emperor Jimmu, 660–581 BC
*** 65th decade BC
*** 64th decade BC
*** 63rd decade BC
*** 62nd decade BC
*** 61st decade BC
** 6th century BC
*** 60th decade BC
*** 59th decade BC
*** Reign of Emperor Suizei, 581–548 BC
*** 58th decade BC
*** 57th decade BC
*** 56th decade BC
*** 55th decade BC
*** Reign of Emperor Annei, 548–510 BC
*** 54th decade BC
*** 53rd decade BC
*** 52nd decade BC
*** 51st decade BC
*** Reign of Emperor Itoku, 510–475 BC
** 5th century BC
*** 50th decade BC
*** 49th decade BC
*** 48th decade BC
*** Reign of Emperor Kōshō, 475–392 BC
*** 47th decade BC
*** 46th decade BC
*** 45th decade BC
*** 44th decade BC
*** 43rd decade BC
*** 42nd decade BC
*** 41st decade BC
** 4th century BC
*** 40th decade BC
*** Reign of Emperor Kōan, 392–290 BC
*** 39th decade BC
*** 38th decade BC
*** 37th decade BC
*** 36th decade BC
*** 35th decade BC
*** 34th decade BC
*** 33rd decade BC
*** 32nd decade BC
*** 31st decade BC
** 3rd century BC
*** 30th decade BC
*** 29th decade BC
*** Reign of Emperor Kōrei, 290–214 BC
*** 28th decade BC
*** 27th decade BC
*** 26th decade BC
*** 25th decade BC
*** 24th decade BC
*** 23rd decade BC
*** 22nd decade BC
*** Reign of Emperor Kōgen, 214–157 BC
*** 21st decade BC
** 2nd century BC
*** 20th decade BC
*** 19th decade BC
*** 18th decade BC
*** 17th decade BC
*** 16th decade BC
*** Reign of Emperor Kaika, 157–97 BC
*** 15th decade BC
*** 14th decade BC
*** 13rd decade BC
*** 12nd decade BC
*** 11st decade BC
** 1st century BC
*** 10th decade BC
*** Reign of Emperor Sujin, 97–29 BC
*** 9th decade BC
*** 8th decade BC
*** 7th decade BC
*** 6th decade BC
*** 5th decade BC
*** 4th decade BC
*** 3rd decade BC
***Reign of Emperor Suinin, 29 BC–AD 71
*** 2nd decade BC
*** 1st decade BC
*1st millennium AD
**1st century AD
***1st decade AD
***2nd decade AD
***3rd decade AD
***4th decade AD
***5th decade AD
***6th decade AD
***7th decade AD
***8th decade AD
***Reign of Emperor Keikō, AD 71–131
***9th decade AD
***10th decade AD
**2nd century AD
***11th decade AD
***12nd decade AD
***13rd decade AD
***14th decade AD
***Reign of Emperor Seimu, 131–192
***15th decade AD
***16th decade AD
***17th decade AD
***18th decade AD
***19th decade AD
***20th decade AD
***Reign of Emperor Chūai, 192–201
**3rd century AD
***21st decade AD
***Regency of Empress Jingū, 201–270
***22nd decade AD
***23rd decade AD
***24th decade AD
***25th decade AD
***26th decade AD
***27th decade AD
***Reign of Emperor Ōjin, 270–313
***28th decade AD
***29th decade AD
***30th decade AD
**4th century AD
***31st decade AD
***32nd decade AD
***Reign of Emperor Nintoku, 313–400
***33rd decade AD
***34th decade AD
***35th decade AD
***36th decade AD
***37th decade AD
***38th decade AD
***39th decade AD
***40th decade AD
***Reign of Emperor Richū, 400–406
**5th century AD
***41st decade AD
***Reign of Emperor Hanzei, 406–412
***42nd decade AD
***Reign of Emperor Ingyō, 412–454
***43rd decade AD
***44th decade AD
***45th decade AD
***46th decade AD
***Reign of Emperor Ankō, 454–457
***Reign of Emperor Yūryaku, 457–480
***47th decade AD
***48th decade AD
***Reign of Emperor Seinei, 480–485
***49th decade AD
***Reign of Emperor Kenzō, 485–488
***Reign of Emperor Ninken, 488–499
***50th decade AD
***Reign of Emperor Buretsu, 499–507
**6th century AD
***51st decade AD
***Reign of Emperor Keitai, 507–534
***52nd decade AD
***53rd decade AD
***54th decade AD
***Reign of Emperor Ankan, 534–536
***Reign of Emperor Senka, 536–540
***Reign of Emperor Kinmei, 540–572
***55th decade AD
***56th decade AD
***57th decade AD
***58th decade AD
***Reign of Emperor Bidatsu, 572–586
***59th decade AD
***Reign of Emperor Yōmei, 586–588
***Reign of Emperor Sushun, 588–593
***60th decade AD
***Reign of Emperor Suiko, 593–629
**7th century AD
***61st decade AD
***62nd decade AD
***63rd decade AD
***Reign of Emperor Jomei, 629–645
***64th decade AD
***65th decade AD
***66th decade AD
***Reign of Empress Saimei, 655–662 ... Saimei (period)
***67th decade AD
*** Reign of Emperor Tenji, 662–672 ... Tenji (period)
***68th decade AD
*** Reign of Emperor Kōbun, 672–673 ... Kōbun (period) or Sujaku (or Suzaku)
*** Reign of Emperor Tenmu, 673–686 ... Tenmu (period) or Hakuhō period
***69th decade AD
*** Reign of Empress Jitō, 687–697 ... Jitō (period)
***70th decade AD
*** Reign of Emperor Monmu, 697–701 ... Monmu (period)
**8th century AD
***71st decade AD
Post-Taika chronology intervals not covered by the nengō system include:
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