Translation guide
The heir apparent to a throne, typically the eldest son of a reigning monarch. In Japanese contexts, this refers specifically to the imperial family.
Referring to the crown prince of Japan
The standard formal title for the crown prince of Japan. Used in official contexts and news.
皇太子殿下が式典に出席された。
His Imperial Highness the Crown Prince attended the ceremony.
Literally 'Eastern Palace', a traditional term for the crown prince or his residence. More literary and historical.
東宮さまは幼い頃から学問に励まれた。
The Crown Prince has devoted himself to learning since childhood.
A formal term for the heir to the throne, used in legal and official documents. Can refer to the crown prince or other designated heir.
皇嗣たる皇子は、皇位継承順位第一位である。
The prince who is the heir to the throne is first in the order of succession.
Referring to the crown prince of a non-Japanese monarchy
Also used for crown princes of other empires, such as historical China or modern European monarchies when translated.
イギリスの皇太子はチャールズ皇太子と呼ばれていた。
The crown prince of the United Kingdom was called Prince Charles.
Specifically for the crown prince of a kingdom (not an empire). Used for European monarchies like Denmark or historical France.
デンマークの王太子はフレデリック王太子です。
The crown prince of Denmark is Crown Prince Frederik.
An archaic term for the heir of a feudal lord or king, used in historical East Asian contexts.
How to address or mention the crown prince in conversation
The respectful form of address, equivalent to 'His Imperial Highness the Crown Prince'.
皇太子殿下にお会いできて光栄です。
It is an honor to meet Your Imperial Highness the Crown Prince.
In modern Japanese, the crown prince is often referred to by his personal name followed by a title, e.g., 徳仁親王 (なるひとしんのう) before his enthronement.
徳仁親王は皇太子として公務に励まれた。
Prince Naruhito carried out his duties as crown prince.
皇太子 is used for the heir of an emperor (帝国), while 王太子 is used for the heir of a king (王国). Japan has an emperor, so 皇太子 is correct for the Japanese crown prince. For European kingdoms like Spain or Sweden, 王太子 is more precise, though 皇太子 is often used loosely in translation.
Do not translate 'crown prince' literally as 王冠の王子 (おうかんのおうじ). This is not a recognized term and sounds unnatural.
The crown prince of Joseon was in the position to succeed the throne.