JLPT N2Everydayを契機に is written

がきっかけで・をきっかけに・を契けい機きに（して）what started it; prompted by

きっかけ is what started something off: the article you happened to read, the friend who asked you along. It is an everyday word. を契けい機きに is its written version, for a turning point.

偶ぐう然ぜん読よんだ記き事じがきっかけで、海かい洋よう問もん題だいに関かん心しんを持もつようになった。

An article I happened to read got me interested in ocean issues.

病びょう気きをきっかけに、彼かれは食しょく生せい活かつを見み直なおした。

His illness prompted him to rethink what he ate.

海かい外がい支し社しゃの設せつ立りつを契けい機きに、社しゃ内ないの公こう用よう語ごが見み直なおされた。

With the opening of an overseas branch, the company's official working language came under review.

How to form it

Noun + がきっかけで／をきっかけに（して）／を契機に（して）

The particles come in pairs, が…で and を…に. For what happened, either pair says the same thing; for a plan, を…に is the usual one. After a verb, add の: 誘さそわれたのがきっかけで.

Before it: What set it off: a meeting, a trip, a book, an illness, a remark.
After it: Something that began or changed: 〜ようになった, 〜始はじめた, 〜ことにした, けんかになった.
Where you'll meet it: Conversation and writing alike for きっかけ. News, company histories and essays for 契けい機き.

In use

私わたしは叔父おじにもらったカメラがきっかけで、写しゃ真しんを仕し事ごとにするようになった。

A camera my uncle gave me is what led me to make photography my job.

友ゆう人じんに誘さそわれたのをきっかけに、週しゅう末まつごとに山やまを歩あるくようになった。

After a friend asked me along, I took to walking in the mountains every weekend.

ささいなことがきっかけで、兄あにとけんかになった。

Something trivial set off a fight with my older brother.

これをきっかけに、日本にほんの歴れき史しをもっと勉べん強きょうしようと思おもいます。

I'm going to take this as my chance to learn more about Japanese history.

A plan: usually を…に.

きっかけ by itself

きっかけ is an ordinary noun, "the thing that started it". Sooner or later someone will ask you this:

A

日本にほん語ごを勉べん強きょうし始はじめたきっかけは何なんですか。

What got you started studying Japanese?

B

高こう校こうのときに見みたアニメがきっかけです。

An anime I watched in high school.

を契けい機きに is the written one

It is usually about a turning point for a company, a town or a country. In conversation it sounds like a history book.

その事じ故こを契けい機きに、全ぜん国こくで安あん全ぜん基き準じゅんが見み直なおされた。

That accident led to a review of safety standards across the country.

Close neighbours

を機にN1

Close to をきっかけに, and a little more formal. Someone takes a milestone as the moment for a fresh start: marriage, a new job, retirement.

定てい年ねん退たい職しょくを機きに、私わたしは地ち域いきのボランティア活かつ動どうに参さん加かし始はじめた。

When I retired, I took the chance to start volunteering in my community.

を境にN1

Draws a line between before and after. It doesn't say the event set the change off.

春はる休やすみを境さかいに、授じゅ業ぎょうの多おおくがオンライン化かされた。

From spring break on, most classes moved online.

Check yourself

1Which particle?

旅りょ行こう（　　）きっかけに、写しゃ真しんを撮とるようになった。

Choose an answer to see why.

2Someone asks you this. What do they want to know?

今いまの仕し事ごとを選えらんだきっかけは何なんですか。

Choose an answer to see why.

More sentences

私わたしはオンライン授じゅ業ぎょうをきっかけに、教きょう育いく方ほう法ほうの研けん究きゅうを始はじめた。

Online classes prompted me to start researching teaching methods.

一いち度どの取しゅ材ざいがきっかけになって、二人ふたりの交こう流りゅうは十じゅう年ねん以い上じょう続つづいた。

A single interview led to a friendship between the two that lasted more than ten years.

卒そつ業ぎょうをきっかけに、私わたしは毎まい朝あさ走はしる習しゅう慣かんをつけた。

Graduating was my cue to get into the habit of running every morning.

制せい度ど改かい革かくを契けい機きにして、組そ織しきは部ぶ門もん間かんの情じょう報ほう共きょう有ゆうを進すすめた。

The organization took the reform of the system as its chance to share more information between departments.