Changes

It was only with the reign of Emperor [[Meiji]] that the system of "one reign, one era" (一世一元 ''issei-ichigen'') came into use, meaning that era names would change only on Imperial succession.  

It was only with the reign of Emperor [[Meiji]] that the system of "one reign, one era" (一世一元 ''issei-ichigen'') came into use, meaning that era names would change only on Imperial succession.  

The first year of an era is called ''gan-nen'' (元年). Subsequent years are counted from the beginning of the following calendar year. For example, the Shōwa era commenced on 25 December 1926, and the second year of Shōwa started a week later on 1 January 1927. It would also imply that 1926 , can be written as both [[Taisho|Taishō]] 15 (the era name of the deceased Emperor) and Shōwa 1.

The first year of an era is called ''gan-nen'' (元年). Subsequent years are counted from the beginning of the following calendar year. For example, the Shōwa era commenced on 25 December 1926, and the second year of Shōwa started a week later on 1 January 1927. It would also imply that 1926, can be written as both [[Taisho|Taishō]] 15 (the era name of the deceased Emperor) and Shōwa 1.

The practice of ''issei-ichigen'' was only formalised in 1979, when the Era Name Law (元号法, ''gengō-hō'') was passed. Thus since 1868, there have been only four ''nengō'': Meiji (明治), Taishō (大正), Shōwa (昭和) and Heisei (平成).<ref>http://www.ndl.go.jp/koyomi/e/</ref>

The practice of ''issei-ichigen'' was only formalised in 1979, when the Era Name Law (元号法, ''gengō-hō'') was passed. Thus since 1868, there have been only four ''nengō'': Meiji (明治), Taishō (大正), Shōwa (昭和) and Heisei (平成).<ref>http://www.ndl.go.jp/koyomi/e/</ref>

Prior to the convention that started with the Meiji Era, the start of a new era could be declared for any number of reasons. The main reasons for declaring a new era would be the first, fifth and 58th years of the "sexagenary cycle" (十干十二支 ''jikkan jūnishi''), based on the [[Chinese]] system of 60 combinations of the two basic cycles, the ten calendar signs and the twelve signs of the [[Chinese zodiac]], the ascension of a new Emperor to the throne, an auspicious event, or a natural disaster.

Prior to the convention that started with the Meiji Era, the start of a new era could be declared for any number of reasons. The main reasons for declaring a new era would be the first, fifth and 58th years of the "sexagenary cycle" (十干十二支 ''jikkan jūnishi''), based on the [[Chinese]] system of 60 combinations of the two basic cycles, the ten calendar signs and the twelve signs of the [[Chinese zodiac]], the ascension of a new Emperor to the throne, an auspicious event, or a natural disaster.

Many periods were only three or four years long and the names had nothing to do with the Emperor of the time. Furthermore, a change of emperor did not necessarily mean an immediate change to a new era; this normally occurred between one to two years after the Emperor's death.<ref>Ryusaku Tsunoda, et. al., comp., Sources of Japanese Tradition, Columbia University Press, 1958</ref>

Many periods were only three or four years long and the names had nothing to do with the Emperor of the time. Furthermore, a change of emperor did not necessarily mean an immediate change to a new era; this normally occurred between one and two years after the Emperor's death.<ref>Ryusaku Tsunoda, et. al., comp., Sources of Japanese Tradition, Columbia University Press, 1958</ref>

The ''nengō'' system in use today was initiated by Emperor Mommu (697 - 707) in 701, after two previous attempts by Emperor Kōtoku in 654, and Emperor Temmu in 686 were abandoned. The current system has continued uninterrupted through today. Eras prior to 701 are generally linked to the first year of the relevant emperor's reign. Thus the first year of the era of Emperor Jimmu from 660 to 581 B.C. is referred to as ''Jimmu-Tennou gannen'' (神武天皇元年), or the "first year of Emperor Jimmu".<ref>Aston, W. G., trans., Nihongi : chronicles of Japan from the earliest times to A.D. 697, London : Allen and Unwin</ref>

The ''nengō'' system in use today was initiated by Emperor Mommu (697 - 707) in 701, after two previous attempts by Emperor Kōtoku in 654, and Emperor Temmu in 686 were abandoned. The current system has continued uninterrupted through today. Eras prior to 701 are generally linked to the first year of the relevant emperor's reign. Thus the first year of the era of Emperor Jimmu from 660 to 581 B.C. is referred to as ''Jimmu-Tennou gannen'' (神武天皇元年), or the "first year of Emperor Jimmu".<ref>Aston, W. G., trans., Nihongi : chronicles of Japan from the earliest times to A.D. 697, London : Allen and Unwin</ref>

===Complete List of Japanese Eras <ref>Varley, H. Paul , "A Chronicle of Gods and Sovereigns: Jinnō Shōtōki of Kitabatake Chikafusa" translated by H. Paul Varley). New York: Columbia University Press, 1980</ref>===

===Complete List of Japanese Eras <ref>Varley, H. Paul , "A Chronicle of Gods and Sovereigns: Jinnō Shōtōki of Kitabatake Chikafusa" translated by H. Paul Varley. New York: Columbia University Press, 1980</ref>===

====Ancient Age (Prior to 1185 AD)====

====Ancient Age (Prior to 1185 AD)====