Before Qin Shi Huang, 朕 was a common first-person pronoun anyone could use. After he unified China in 221 BC, he decreed that only the emperor could use it — and it stayed that way for over 2,000 years.
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Used in historical dramas and novels. In modern slang, people sometimes jokingly say 朕 to sound imperious.
The left 月 is the indexing Kangxi radical for 朕. Originally 朕 depicted two hands raising an offering over a boat (舟); the 舟 element flattened into the 月 shape through script reform, and lookup follows the modern 月-radical placement.
The right component evolved from a pair of hands lifting an object — a posture of ceremonial offering. This raised-hands imagery is the source of 朕's classical meaning 'I (the sovereign)', as the king ritually offered to ancestors on behalf of the realm.
