〜を契機に (o keiki ni)

JLPT N2 Prompted by ~ — using an event as a turning point.

Meaning

“Triggered by ~ / taking ~ as an opportunity.” A significant event that leads to a lasting change. Formal.

Formation

Noun + を契機に(して)

Verb (plain) + の / こと + を契機に

Examples

病気を契機に、彼は生活を見直した。

Byōki o keiki ni, kare wa seikatsu o minaoshita. — Prompted by his illness, he reviewed his lifestyle.

子どもが生まれたことを契機に、たばこをやめた。

Kodomo ga umareta koto o keiki ni, tabako o yameta. — Taking his child's birth as a turning point, he quit smoking.

留学を契機に、世界に興味を持つようになった。

Ryūgaku o keiki ni, sekai ni kyōmi o motsu yō ni natta. — Studying abroad was the catalyst for my interest in the world.

How it works

It marks a notable event as the starting point of a change. It's formal and written; 〜をきっかけに is the everyday equivalent.

The change is usually deliberate and lasting, not a one-off reaction.

Compared with similar expressions

• 〜を契機に — “prompted by,” formal turning point

• 〜をきっかけに — same meaning, more casual/common

• 〜を機に — shortened, formal set phrase

Common mistakes

• 契機 is read けいき.

• For verbs, nominalize first: 〜のを / 〜ことを契機に.

Related grammar

• 〜をきっかけに — triggered by (casual)

• 〜て以来 — ever since ~

• 〜てから — after ~