# をいいことに: to take advantage of ~ > Learn how to use をいいことに, a JLPT N1 Japanese grammar point meaning to take advantage of, with formation, examples, comparisons to を幸いに, and practice. JLPT level: N1 · Updated: 2026-05-18 · Canonical: https://hane-app.com/blog/n1-o-ii-koto-ni/ **をいいことに** means **to take advantage of ~**. It is a **JLPT N1** Japanese grammar pattern used to show that someone exploits a situation, often for selfish gain, treating the circumstance as a good excuse. This grammar point appears frequently in critiques, editorials, narrative fiction, and JLPT N1 reading passages. If you need to express that someone is leveraging a condition for their own benefit — usually with a disapproving edge — **をいいことに** is a sharp tool to keep in your active vocabulary. ## What does をいいことに mean? Use **をいいことに** when you want to say that a person treats a certain situation as *a good thing* and exploits it to their advantage. The nuance is almost always negative or critical, though occasionally neutral when no moral judgement is implied. Natural translations include: - to take advantage of; to exploit; to abuse; to make use of The best translation depends on the sentence. Look first at the speaker's attitude — is it criticism, observation, or simple description? — then choose the English phrase that fits that tone. ## How to form をいいことに Attach **をいいことに** directly to a noun that names the situation being exploited.
[Noun] + をいいことに → [exploitative action]
The noun is often a verb nominalized by の or こと, or a plain noun describing a state (弱み(よわみ), 忙し(いそがし)さ, 不在(ふざい), etc.). Examples of the pattern: - 彼(かれ)の弱み(よわみ)をいいことに - 忙しい(いそがしい)のをいいことに - 親(おや)の不在(ふざい)をいいことに The phrase before をいいことに sets up the "good excuse" that enables the following action. ## When is をいいことに used? Use **をいいことに** in situations like: - describing someone exploiting another's weakness, ignorance, or kindness - criticizing a person who uses a chaotic or unsupervised moment to act selfishly - explaining how a convenient circumstance enabled irresponsible behavior - (rarely) noting a neutral advantage taken of a favourable condition Tone and register: - predominantly written, often in commentary, news, or formal speech - strong critical flavour when used in everyday conversation - common in test questions and JLPT N1 reading comprehension ## をいいことに example sentences
彼(かれ)は上司じょうしの不在ふざいをいいことに、いつも早退そうたいしている。
He always leaves early, taking advantage of his boss’s absence.
職場(しょくば) 悪用(あくよう)
彼(かれ)の無知むちをいいことに、詐欺師さぎしは大金たいきんを騙だまし取とった。
The con artist tricked him out of a fortune, exploiting his ignorance.
詐欺(さぎ) 批判(ひはん)
親おやの優やさしさをいいことに、甘あまやかされて育そだってしまった。
Taking full advantage of their parents’ kindness, the child grew up spoiled.
家族(かぞく) 弊害(へいがい)
忙いそがしいのをいいことに、運動うんどうを完全かんぜんにサボっている。
Using busyness as a convenient excuse, I’ve completely skipped exercising.
言い訳(いいわけ) 自嘲(じちょう)
この静しずかな環境かんきょうをいいことに、集中しゅうちゅうして勉強べんきょうできた。
I was able to concentrate on studying, making the most of this quiet environment.
中立(ちゅうりつ) 好機(こうき)
Look how each sentence treats をいいことに — the first four carry a critical or self-deprecating tone, while the fifth simply states a neutral advantage. The grammar itself doesn't mandate negativity, but context colours it heavily. ## Nuance of をいいことに The heart of **をいいことに** is treating a situation as *a good thing (いいこと)* in a way that benefits oneself, often at another’s expense or in a manner that invites disapproval. The speaker usually signals that this is illegitimate or morally questionable. Think of it as “acting like this inconvenience/problem/weakness of someone else is actually a convenient chance for me.” The underlying judgement can range from sharp criticism (“he exploited her kindness”) to milder self-mockery (“I used being busy as an excuse to be lazy”). Compared to more neutral expressions like を利用(りよう)して, をいいことに implies a stronger emotional charge — the writer or speaker is not just describing the fact but also conveying a stance.
⚠️
Even though をいいことに isn’t grammatically restricted to negative contexts, the majority of natural examples include implied blame. If you want to sound purely factual, consider を利(り) (り) 用(よう) (よう) して or を活(かつ) (い) かして. Reserve をいいことに for when attitude matters.
## をいいことに vs を幸い(さいわい)に Both structures attach to a noun and show that a situation is taken advantage of, but their moral colour is different.
をいいことに
often negative — exploiting a situation that shouldn’t be an advantage
Critical stance, abuse of trust or weakness
雨(あめ)が降っ(ふっ)たのをいいことに、一日中(いちにちちゅう)ゴロゴロして過ごし(すごし)た。
Taking the rain as an excuse, I lazed around all day. (self-critical)
vs
を幸(さち) (さいわ) いに
usually positive — making the most of a genuinely favourable turn
Appreciative tone, a chance well used
雨(あめ)が降っ(ふっ)たのを幸い(さいわい)に、家(いえ)でゆっくり読書(どくしょ)を楽しん(たのしん)だ。
Taking the rain as a welcome opportunity, I enjoyed reading at home.
Notice how the same rain event can be framed with opposite nuance. Choose **をいいことに** when there’s a sense of impropriety; choose **を幸い(さいわい)に** when you want to show gratitude or positivity. ## Common mistakes with をいいことに Watch out for these pitfalls:
❌
風邪(かぜ)をいいことに会社(かいしゃ)を休ん(やすん)だ。
Unless you are pretending to be sick or using a mild cold as a trick, 風邪(かぜ)をいいことに sounds unnatural — a cold isn’t normally something you’d exploit. The grammar requires a situation that feels like a “convenient excuse” for a questionable action.
✅
風邪(かぜ)を口実(こうじつ)に会社(かいしゃ)を休ん(やすん)だ。
When you use illness simply as a pretext, 口実(こうじつ)に or 理由(りゆう)に is safer. Alternatively, if you really mean “I took advantage of having a cold to skip work” in a self-mocking way, をいいことに is possible, but the nuance must be clearly exploitative.
❌
静か(しずか)さをいいことに、よく眠れ(ねむれ)た。
This is grammatically correct but pragmatically odd: “taking advantage of the quietness” doesn’t imply any benefit gained at someone else’s cost; it’s just a pleasant circumstance. Without a hint of exploitation, をいいことに feels misplaced.
✅
静か(しずか)さのおかげで、よく眠れ(ねむれ)た。
For purely favourable conditions that don’t involve exploiting a weak spot, use おかげで or ために.
A simple rule of thumb: if you can replace “taking advantage of” with “using … as a good excuse to do something questionable,” then をいいことに fits; if not, choose a different pattern. ## Is をいいことに on the JLPT?
N1

をいいことに is standard JLPT N1 grammar. It appears regularly in reading comprehension — editorial columns, short stories, and opinion pieces.

✔ Recognize the exploitative nuance in context

✔ Distinguish between をいいことに and neutral alternatives like を踏まえ(ふまえ)て or を経(へ)て

✔ Answer “usage” questions that ask about the writer’s attitude

Test makers often pair をいいことに with a vocabulary item that reinforces the negative shade (悪用(あくよう), 搾取(さくしゅ), 怠惰(たいだ), etc.). When you see that combination, expect a question about criticism or moral stance. ## Practice questions for をいいことに
1
Write a sentence where a student takes advantage of a substitute teacher’s lack of authority.
学校(がっこう)
2
Describe a situation where someone uses being “new” or inexperienced as an excuse to avoid responsibility, using をいいことに.
職場(しょくば)
3
Take the neutral sentence 「雨(あめ)で試合(しあい)が中止(ちゅうし)になった。家(いえ)で勉強(べんきょう)した。」 and rewrite it twice: once with をいいことに (adding a negative spin) and once with を幸い(さいわい)に (adding a positive spin). Explain the shift.
比較(ひかく)
4
Read this excerpt: “その政治家(せいじか)は混乱(こんらん)をいいことに、私腹(しふく)を肥やし(こやし)た。” What judgement does the author imply? How would the nuance change if 利用(りよう)して replaced をいいことに?
読解(どっかい)
Keep your own sentences simple at first. Once the exploitative weight feels natural, add more context to make the speaker’s stance unmistakable. ## Learning path for をいいことに
1
Memorize the formation: Noun + をいいことに. Make a few mechanical drills with different nouns (弱み(よわみ)、忙し(いそがし)さ、不在(ふざい)、無知(むち)).
2
Compare with を幸い(さいわい)に and を利用(りよう)して. Write one event described with all three and note how the speaker’s judgement changes.
3
Read three authentic examples from news headlines or novels (search “をいいことに” on NHK or Yahoo). Classify each as negative, critical, or neutral. Pay attention to the verbs that follow (盗む(ぬすむ)、怠ける(なまける)、騙す(だます)、etc.).
4
Write a short opinion piece (100–150 characters) about a social issue, using をいいことに to criticise a particular behaviour. Then re-read it with a tutor or language partner for naturalness.
## Related grammar to review next These patterns share the structure of noun + particle + こと/に, and they often appear in the same advanced reading passages. Understanding how they differ from をいいことに will sharpen your test performance. - [を踏まえ(ふまえ)て](/blog/n1-o-fumaete/) — *based on, in light of*; factual grounding, not exploitation. - [を経(へ)て](/blog/n1-o-hete/) — *through, after undergoing*; focuses on process, not advantage. - [を控え(ひかえ)て](/blog/n1-o-hikaete/) — *with ~ approaching, in anticipation of*; temporal/spatial. - [を顧み(かえりみ)ずも顧み(かえりみ)ず](/blog/n1-o-kaerimizu-mo-kaerimizu/) — *without regard for, braving*; self-sacrifice, not selfish gain. ## Learn をいいことに with Hane If you want to cement **をいいことに** alongside the related patterns above, Hane offers bite-sized, contextual practice that helps you internalize nuanced grammar. Browse more lessons here: - [All grammar lessons](/blog/) - [JLPT N1 grammar lessons](/blog/n1/)