The Monmu period is a chronological timeframe during the Asuka period of Japanese history. The Mommu period describes a span of years which were considered to have begun in the 1357th year of the Yamato dynasty.[1]

This periodization is consistent with the traditional dates asserted for the reign of Emperor Monmu, from 697 through 707.[2]


The adoption of the Sexagenary cycle calendar (Jikkan Jūnishi) in Japan is attributed to Empress Suiko in 604;[3] and this Chinese calendar continued in use throughout the Mommu period.

In 645, the system of Japanese era names (年号, nengō, "year name") was introduced.[4] However, after the reign of Emperor Kōtoku, this method of segmenting time was temporarily abandoned or allowed to lapse. This interval continued during the Monmu period.

Neither Empress Mommu's reign nor the Monmu periodization are included in the list of nengō for this explicit duration of time, which comes after Suchō and before Taihō.

In the post-Taika or pre-Taihō chronology, the first year of Emperor Monmu's reign (文武天皇元年 or 文武統皇1年) is also construed as the first year of the Mommu period (文武1年).[5]

Non-nengō period

Non-nengō periods in the pre-Taihō calendar were published in 1880 by William Bramsen.[1] These were refined in 1952 by Paul Tsuchihashi in Japanese Chronological Tables from 601 to 1872.[5]

The pre-Tahiō calendar included two non-nengō gaps or intervals in the chronological series:

  • Taika, August 645–February 650.[6]
  • Hakuchi, February 650–December 654.[7]
    • Non-nengō dating systems
  • Shuchō, July–September 686.[8]
    • Non-nengō dating systems
  • Taihō, March 701–May 704.[6]

Nengō were not promulgated (or were allowed to lapse) during the gap years between Hakuchi and Shuchō, and in another gap between Shuchō and Taihō.

Concurrent Chronologies
Non-nengō periods Nengō eras Shinengō[9] Yamato dynasty duration Western calendar dates
Taika[6] 1305 645[10]
Hakuchi[7] 1310 650[11]
Saimei's reign[1] 1315 655[12]
Tenji's reign[1] 1322 662[13]
Kōbun's reign[14] Sujaku[15] 1332[1] 672[16]
Temmu's reign Hakuhō[17] 1333[1] 673[18]
Suchō[8] 1346 686[19]
Jitō's reign[1] 1347 687[20]
Taika[21] 1350 695[21]
Mommu's reign[1] 1357 697[22]
Taihō[6] 1361 701[23]

Events of the Mommu period

See also


  1. ^ a b c d e f g h Murray, David. (1894). The Story of Japan, p. 402, p. 402, at Google Books, citing William Bramsen. (1880). Japanese Chronological Tables, pp. 54–55, p. 54, at Google Books; compare, the Japanese National Diet Library website explains that "Japan organized its first calendar in the 12th year of Suiko (604)", which was a pre-nengō time frame.
  2. ^ Murray, p. 402, p. 402, at Google Books; the system of counting from year-periods (nengō) do not ordinarily overlap with the reigns of the early monarchs; and generally, a new one was chosen whenever it was deemed necessary to commemorate an auspicious or ward off a malign event.
  3. ^ Nussbaum, Louis-Frédéric. (2005). "Jikkan Jūnishi" in Japan Encyclopedia, p. 420, p. 420, at Google Books; n.b., Louis-Frédéric is pseudonym of Louis-Frédéric Nussbaum, see Deutsche Nationalbibliothek Authority File Archived 2012-05-24 at
  4. ^ Titsingh, Isaac. (1834). Annales des empereurs du Japon, p. 30., p. 30, at Google Books
  5. ^ a b Tsuchihashi, Paul. (1952). Japanese Chronological Tables from 601 to 1872, p. 16.
  6. ^ a b c d Nussbaum, "Taika" at p. 924., p. 924, at Google Books
  7. ^ a b Nussbaum, "Hakuchi" at p. 280, p. 280, at Google Books.
  8. ^ a b Nussbaum, "Shuchō" at p. 889, p. 889, at Google Books.
  9. ^ Shinengō used prior to the reestablishment of the nengō system in 701 are usually called itsunengō (逸年号). A list of shinengō and more information can be seen in the Japanese Wikipedia page ja:私年号.
  10. ^ NengoCalc (645) 大化 Taika, online conversion of Japanese dates into their Western equivalents; calculation is based on tables from Tsuchihashi and Zöllner.
  11. ^ NengoCalc (650) 白雉 Hakuchi
  12. ^ NengoCalc (655) 斉明 Saimei
  13. ^ NengoCalc (622) 天智 Tenji
  14. ^ Brown, Delmer M. et al. (1979). Gukanshō, p. 268 n39., p. 268, at Google Books; post-Meiji historians identify the reign of Emperor Kōbun between the reigns of Emperor Tenji and Emperor Temmu, but pre-Meiji historians did not construe Prince Ōtomo in the traditional order of succession; compare Ponsonby-Fane, Richard. (1959). The Imperial House of Japan, p. 52; and see Imperial Household Agency (Kunaichō): 天智天皇 (38)
  15. ^ Murray, p. 402, p. 402, at Google Books; Sujaku is also known as an Itsunengō (逸年号)
  16. ^ NengoCalc (672) 弘文 Kōbun
  17. ^ Murray, p. 402, p. 402, at Google Books; Hakuhō, also known as Itsunengō; compare Nussbaum, "Hakuhō" at p. 280, p. 280, at Google Books; Hakuhou jidai, JAANUS (Japanese Architecture and Art Net Users System), 2001; retrieved 16 September 2009.
  18. ^ NengoCalc (673) 弘文 Temmu
  19. ^ NengoCalc (686) 朱鳥 Suchō
  20. ^ NengoCalc (687) 持統 Jitō
  21. ^ a b Brown, p. 270, p. 270, at Google Books; excerpt, "The eras that fell in this reign were: (1) the remaining seven years of Shuchō [(686+7=692?)]; and (2) Taika, which was four years long [695-698]. (The first year of this era was kinoto-hitsuji [695].) ...In the third year of the Taka era [697], Empress Jitō yielded the throne to the Crown Prince."
  22. ^ NengoCalc (697) 文武 Mommu
  23. ^ NengoCalc (701) 大宝 Taihō
  24. ^ Varley, H. Paul. (1980). Jinnō Shōtōki, p. 44. [A distinct act of senso is unrecognized prior to Emperor Tenji; and all sovereigns except Jitō, Yōzei, Go-Toba, and Fushimi have senso and sokui in the same year until the reign of Go-Murakami.]


Preceded by— Nengō in abeyance Succeeded byTaihō era Preceded byJitō period Monmu period Reign of Emperor Monmu(686–697)