The emperor called himself "I" because Ying Zheng, the founder of the emperor's name, demanded that the later emperors continue to use it. So what does the word "I" mean?
After the first emperor of Qin unified China, he thought that the name of the king was not worthy of his achievements. After the discussion among all the officials, he thought that Ying Zheng should use the name of the emperor to honor himself. After Ying Zheng became the first emperor, he stipulated the first person. Only the Emperor himself can call himself "I". All subjects should not use the person of "I". They can use me, Yu, I, I, I, I, Qu Qu, bu CAI and so on. Later emperors continued to use this rule. When the emperor called himself "I", I became the exclusive pronoun of the emperor.
My original meaning is boat sewing. It is also extended to signs and symptoms. Those who say "I augur" are very few, such as the crack of a boat, or the crack of a turtle's shell. Boat gap refers to the gap between the two wooden boards of a wooden boat. It is a very small analogy between being modest and being virtuous, similar to the meaning of being widowed. In the pre-Qin period, my original intention was "my" or "I", which could be used by everyone. For example, Qu Yuan wrote that "the Miao descendants of emperor Gaoyang, my emperor was called Bo Yong".
The emperor called himself "I", while the titles of king, Duke, marquis, Bo, Zi and man under the emperor called themselves. For example, widows, orphans, Buyu and so on. The above three terms can only be used by princes and princes, but also by ordinary people. As the Duke and king of Wei, Cao mengde can only call himself lonely, but not me. When Cao Pi became the emperor, he called himself I, and pursued Cao Cao as the emperor. Then Cao Cao could call himself I under Jiuquan.
China's vassal states can't call me, for example, the king of Korea calls himself the king or the widowed; after Korea broke away from the control of the Qing Dynasty, it established the Korean Empire, and its king began to call himself I. The monarchs of Vietnam, Myanmar, Ryukyu, Siam and other affiliated countries are only kings, not emperors. For a long time, Japan was not a subsidiary country of China, and the monarch also called himself the emperor. Therefore, the emperor of Japan usually also called himself the emperor of China. Now, the only one who seriously calls himself the emperor of Japan is probably the emperor of Japan.