を契機に details

をけいきに

seizing N as the turning point; treating N as the occasion to act

病気びょうきを患わずらったことを契機けいきに、彼かれは生活せいかつ習慣しゅうかんを大おおきく見直みなおした。

byouki o wazuratta koto o keiki ni, kare wa seikatsu shuukan o ookiku minaoshita.

Falling ill was the turning point that led him to overhaul his lifestyle habits. neutral

定年ていねん退職たいしょくを契機けいきに、田舎いなかで新あたらしい生活せいかつを始はじめることにした。

teinen taishoku o keiki ni, inaka de atarashii seikatsu o hajimeru koto ni shita.

Taking my retirement as the turning point, I decided to start a new life in the countryside. neutral

Examples

seizing N as the turning point — a significant event someone deliberately treats as the occasion to act or change

病気びょうきを患わずらったことを契機けいきに、彼かれは生活せいかつ習慣しゅうかんを大おおきく見直みなおした。

byouki o wazuratta koto o keiki ni, kare wa seikatsu shuukan o ookiku minaoshita.

Falling ill was the turning point that led him to overhaul his lifestyle habits. neutral

定年ていねん退職たいしょくを契機けいきに、田舎いなかで新あたらしい生活せいかつを始はじめることにした。

teinen taishoku o keiki ni, inaka de atarashii seikatsu o hajimeru koto ni shita.

Taking my retirement as the turning point, I decided to start a new life in the countryside. neutral

今回こんかいの事故じこを契機けいきとして、安全あんぜん管理かんり体制たいせいを全面的ぜんめんてきに見直みなおすこととなりました。

konkai no jiko o keiki to shite, anzen kanri taisei o zenmenteki ni minaosu koto to narimashita.

Taking this accident as the occasion, we will thoroughly overhaul our safety management system. formal

を契機として — とする-based tail is the more bookish register still — corporate announcements and official reports. をきっかけに substitutes grammatically but reads lighter — it makes the trigger incidental where を契機に makes it consequential.

をきっかけに
Both mean "with X as what set it off," and をきっかけに takes deliberately chosen triggers just as readily as chance ones (結婚けっこんをきっかけに仕事しごとを辞やめた) — the real axis is register and WEIGHT, not intent. を契機けいきに is written/formal and wants both the trigger and the resulting change to be consequential (歴史的れきしてきな事件じけんを契機に法ほう改正かいせいが進すすんだ), while をきっかけに is register-neutral and happily takes a trivial, everyday trigger with a small effect (友人ゆうじんの一言ひとことをきっかけに笑わらってしまった) — pin that same small trigger onto を契機に (？一言ひとことを契機に笑ってしまった) and it reads as bathos, self-importantly formal for something that minor.