Translation guide
The English word "reign" has two main uses: the period of rule by a monarch, and the act of ruling. Japanese expresses these with different nouns and verbs, and the choice depends on whether you are talking about a specific era name, the general concept of a reign, or the action of reigning.
Referring to the time during which a monarch rules.
during the reign of Queen Victoria · a long and peaceful reign · the reign of Emperor Meiji
General term for a monarch's reign or rule. Used in historical or formal contexts.
エリザベス女王の治世は長かった。
Queen Elizabeth's reign was long.
Specifically the period during which a monarch is on the throne. More formal and precise than 治世.
天皇の在位期間は30年を超えた。
The emperor's reign exceeded 30 years.
Literally "the era of ~", used with a monarch's name to refer to their reign in a broader historical sense.
ヴィクトリア女王の時代、イギリスは大きく発展した。
During Queen Victoria's reign, Britain developed greatly.
For Japanese emperors, the reign is typically referred to by the era name (e.g., 明治, 大正, 昭和, 平成, 令和). This is the most natural way to talk about a Japanese emperor's reign.
明治時代、日本は急速に近代化した。
During the Meiji era (Emperor Meiji's reign), Japan modernized rapidly.
昭和天皇の治世は戦争と復興の時代だった。
The reign of Emperor Showa was a time of war and reconstruction.
Describing the action of a monarch holding power.
The king reigned for 50 years. · She reigned over a vast empire. · He reigned wisely.
To rule or govern. Used for monarchs and leaders. Transitive verb.
その王は国を平和に治めた。
The king reigned over the country peacefully.
To reign or govern, often used in formal or political contexts. Can be used for both monarchs and governments.
女王は60年以上にわたって統治した。
The queen reigned for over 60 years.
To reign (over), to dominate. Implies a more majestic or absolute rule. Often used metaphorically.
その皇帝は広大な領土に君臨した。
The emperor reigned over a vast territory.
Phrase meaning "during the reign of ~", used to describe events that happened while a monarch was ruling.
エリザベス1世の治世の間に、イギリスは海軍力を強化した。
During the reign of Elizabeth I, England strengthened its naval power.
Referring to a period when something is dominant or prevalent, not necessarily a monarch.
the reign of terror · the reign of digital technology · his reign as champion
Domination or control. Can be used figuratively for non-monarchical reigns.
恐怖政治の支配が続いた。
The reign of terror continued.
Heyday or golden age. Used when referring to the peak period of someone's influence or success.
As with monarchs, this pattern can be used figuratively to mean "the era of ~".
デジタル技術の時代が到来した。
The reign of digital technology has arrived.
治世 is a noun meaning "reign" (period). To say "reign" as an action, use verbs like 治める or 統治する.
When referring to the reign of a Japanese emperor, it is most natural to use the era name (元号) plus 時代 or の時に. For example, "during the reign of Emperor Meiji" is 明治時代に or 明治の時に.
彼のチャンピオンとしての全盛期は長く続いた。
His reign as champion lasted a long time.