The year number is a name used by China feudal dynasty and contemporary Japanese to record the year. Generally initiated by the monarch. There was no title from the pre-Qin Dynasty to the early Han Dynasty, which was first created by Emperor Wu of the Han Dynasty after he ascended the throne. The founding year is Jianyuan.
Since then, a system has been formed. Emperors of past dynasties generally changed their titles when they encountered great events and important events, such as good or bad luck, internal troubles and foreign invasion. An emperor uses one to a dozen titles.
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The use of China year number is very complicated. Regimes that coexist at the same time often have their own titles. Other regimes exchange RMB several times a year, and the figures overlap in several years.
There are also regimes that do not build their own country names, but use the country names of previous dynasties or other regimes. For example, the Tianfu year number at the end of the Jin Dynasty took nine years and was changed to the first year of shipment.
Three years later, Liu Zhiyuan proclaimed himself emperor. He did not build his own title, nor did he continue to use it, but inherited Tianfu for twelve years. There are also many year numbers that are used repeatedly in different periods.
In some vassal states in the history of China, the title of China was usually extended. For example, when Korea and Ryukyu were vassals of China, they also used the title of Emperor China, which was a sign of loyalty to China.
Take ancient Korea as an example. After the demise of the Ming Dynasty, except for the correspondence with the documents of the Qing Dynasty, the internal official documents all used the year number of the Ming Dynasty and changed it to the era when China was in power or the king was in power. As for the people, there are still people who insist on using the year number of Chongzhen, even those who have been in Chongzhen for more than 300 years, much like Zheng.
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