Japanese grammar

What does ～を境に(して) mean? Japanese grammar N1

～を境に(して) means taking… as a turning point; ever since….

Quick facts
Level (estimated, JLPT framework)	N1
Structure	N (turning point) + を境に(して)
Romaji	wosakaini(shite)
Meaning	taking… as a turning point; ever since…

Forming it

Noun (event)	父の死 + を境に
Noun (point in time)	五月 + を境に

How to use it

States a point in time/event as the BOUNDARY, after which the situation changes noticeably.

「～を境に(して)」 = taking A as the BOUNDARY: before and after A are completely different.
A is a point in time or a turning-point event; the following clause states a clear CHANGE.
Different from 「～を機に」 (N1-163, taking A as the opportunity to deliberately do B): 「を境に」 emphasizes the before/after change, usually NOT deliberate.

Examples

父(ちち)の死(し)を境(さかい)に、彼(かれ)の生(い)き方(かた)は一変(いっぺん)した。
His father’s death marked a turning point after which his way of life changed entirely.
五月(ごがつ)を境(さかい)に、客足(きゃくあし)が急(きゅう)に減(へ)り始(はじ)めた。
From May onward, foot traffic began to fall sharply.

Keep in mind

The clause that follows states a clear change.
Often used with 変わる・増える・減る.

Common mistakes

Wrong卒業(そつぎょう)を境(さかい)に、新(あたら)しい仕事(しごと)を探(さが)し始(はじ)めた。

On the occasion of graduating, I began looking for a new job.

Correct卒業(そつぎょう)を機(き)に、新(あたら)しい仕事(しごと)を探(さが)し始(はじ)めた。

Deliberately TAKING the opportunity A to do B uses 「を機に」; 「を境に」 emphasizes the before/after change.
Wrong五月(ごがつ)を境(さかい)に、何(なに)も変(か)わらなかった。

Taking May as the turning point, nothing changed.

Correct五月(ごがつ)を境(さかい)に、状況(じょうきょう)が大(おお)きく変(か)わった。

The following clause must state a CHANGE; without a change, this pattern is meaningless.

Exam tips

「を境に」 = a boundary marker, before/after completely different; different from 「を機に」 (taking an opportunity, deliberate).

Related patterns

All N1 grammar →