Jogan no chi (Glorious Jogan rule) (貞観の治)
Jogan no chi (Glorious Jogan rule) indicates the politics performed during the Jogan era (Tang, 627 - 649) and the reign of the second Emperor Taiso (Tang tai zong) in the Tang Dynasty (618 - 907) in China. It is said that the country was governed most peacefully during this period in the Chinese history. The reign at that time was deemed to be an ideal period in terms of politics by the succeeding generations.
In the Dynasty period in which the name of an era was changed even due to a very slightly extraordinary event, the same gengo (an era name) was rarely used continually for as long as 23 years. It indicates how stably the country was governed during the reign.
The following words that represent this era are shown in shijitsugan (a history book of China, in which the historical fact of Warring States period to the late of five dynasties was written in chronological order): "－海内升平，路不拾遺，外戸不閉，商旅野宿焉". There is a peace reign over the land, and things left behind on a lane shall never be stolen. It is said to be so safe that the doors of houses are never shut up and traveling merchants can sleep under the stars.
The politics of this era was compiled in documents called "Joganseiyo" (a book written about Taiso, the second Emperor of Tang Dynasty in China) as assembled dialogues between Tang tai zong and ministers. It was used as a textbook for politics for a long period of time.
Jogan no chi (Glorious Jogan rule) in Japan
In Japan, there used to be an era called "Jogan" (Japan) during the reign of Emperor Seiwa in early Heian period, and a reign called "Jogan no chi" (Glorious Jogan rule" was present.
During the period, FUJIWARA no Yoshifusa, who was the first subject appointed as Daijo-daijin (Grand Minister) in the reign of the former Emperor Montoku (except FUJIWARA no Nakamaro and Dokyo) and his adopted child (nephew) FUJIWARA no Mototsune attained the ascendancy of the Fujiwara clan including early Sekkanseiji (the power of Sekkan, meaning regents and advisers, governs the country) and so on.
But there were such events as the prevalence of infectious diseases and eruption of Mt. Fuji. Though they had unstable factors such as the Otenmon Incident, affirmative measures were taken to encourage land reclamation, compile Jogan Kyakushiki Code (Regulations and Procedures of the Jogan Era), and mint Jogan Eiho (coins minted in Jogan era) and the politics was stable. In 876, Emperor Seiwa abdicated the throne in favor of his son; a prince, Imperial Prince Sadaakira (Emperor Yozei), and Mototsune, who was the uncle of Imperial Prince Sadaaki, was appointed as Sessho (regent).
As the maternal grandfather of the emperor, the late FUJIWARA no Nagara, who was the father of Mototsune, was raised to Shoichii Dajo Daijin (Senior First Rank Grand Minister of State) posthumously. However, in 877, the following year, the name of the era Jogan, which had been used continually for 19 years was changed to Gengyo.