(いっしょう)(いちど)

いっしょういちど
expression
once in a lifetime; once-in-a-lifetime
1. once in a lifetime; a unique and unrepeatable occasion
Describes something that happens only once in one's entire life, or an opportunity so rare that it should be treated with great importance.
一生(いっしょう)一度(いちど)経験(けいけん)だった。
It was a once-in-a-lifetime experience.
結婚式(けっこんしき)一生(いっしょう)一度(いちど)のことだから、後悔(こうかい)したくない。
A wedding is a once-in-a-lifetime event, so I don't want to have regrets.
一生(いっしょう)一度(いちど)のチャンスを(のが)すわけにはいかない。
I can't afford to let a once-in-a-lifetime chance slip away.

A four-character expression composed of 一生(いっしょう) (one's whole life) and 一度(いちど) (one time). Emphasizes the rarity and irreplaceability of an occasion or opportunity.

COMMON COLLOCATIONS:

  • 一生(いっしょう)一度(いちど)経験(けいけん): once-in-a-lifetime experience
  • 一生(いっしょう)一度(いちど)のチャンス: once-in-a-lifetime chance
  • 一生(いっしょう)一度(いちど)(おも)(): a lifetime memory
  • 一生(いっしょう)一度(いちど)()(もの): a once-in-a-lifetime purchase

CULTURAL NOTE:
Closely related to the tea ceremony concept of 一期一会(いちごいちえ) (one time, one meeting), which teaches that every encounter should be treasured as if it may never happen again.

SIMILAR EXPRESSIONS:

  • 一期一会(いちごいちえ): treasure every encounter — philosophical concept from tea ceremony
  • 一生(いっしょう)一度(いちど): once in a lifetime — the particle-connected variant with identical meaning
  • 滅多(めった)にない: rare, seldom — describes rarity but without the lifetime emphasis