Meaning & Usage
✨ Basic Meaning
Precisely; definitely; it is X that…
🎯 Primary Function
To strongly emphasize the word or phrase immediately preceding it, often creating a contrast or highlighting a specific reason, time, or person as the exclusive factor.
📋 Grammar Structure
Noun / Particle Phrase / Verb Plain Form + こそ
I-adjective Plain Form + からこそ
Na-adjective Stem + だからこそ
Verb Negative Plain Form + からこそ / Noun + でなくてこそ
🎭 Usage Contexts
Formal Situations
Used to make strong, assertive statements or give profound compliments.
Informal Situations
Commonly used in conversational set phrases (e.g., こちらこそ) and for passionate emphasis.
Written Language
Frequent in argumentative essays, persuasive writing, and formal communications to highlight key points.
Spoken Language
Highly frequent, particularly for emphasis and mutual politeness.
💡 Common Applications
Emphasizing the Subject or Object
Used after a noun to put exclusive emphasis on that noun, often implying exclusion of others. Replaces particles like が or は, but often follows に, で, や, etc.
Example: この企画は、社長にこそ見てほしい。
Highlighting an Essential Reason (からこそ)
Used after the plain form of a verb/adjective followed by から to strongly assert that the preceding reason is the *only* or *most important* reason for the result (often a positive one).
Example: 苦労したからこそ、今の幸せがある。
Used in Set Phrases for Mutual Politeness
Used in common greetings like こちらこそ to return a compliment or acknowledgment, meaning “I feel the same way,” or “The pleasure/honor is mine, too.”
Example: こちらこそ、いつもお世話になっております。
Frequency
High, especially in speeches, formal statements, and conversational greetings.
Difficulty
Intermediate (JLPT N3 – N2)
Tag:
Example Sentences
Example #1
あなたこそ、このプロジェクトのリーダーにふさわしい。
Furigana: あなたこそ、このプロジェクトのリーダーにふさわしい。
Romaji: Anata koso, kono purojekuto no riidā ni fusawashii.
English: It is precisely you who is suitable to be the leader of this project.
Example #2
困難を乗り越えたからこそ、人は成長できる。
Furigana: こんなんをのりこえたからこそ、ひとはせいちょうできる。
Romaji: Konnan o norikoeta kara koso, hito wa seichō dekiru.
English: It is precisely because they overcome difficulties that people can grow.
Example #3
今こそ、環境問題について真剣に考えるべきだ。
Furigana: いまこそ、かんきょうもんだいについてしんけんにかんがえるべきだ。
Romaji: Ima koso, kankyō mondai ni tsuite shinken ni kangaeru beki da.
English: Now is precisely the time we should seriously think about environmental issues.
Example #4
「また会いましょう。」「ええ、こちらこそ。」
Furigana: 「またあいましょう。」「ええ、こちらこそ。」
Romaji: “Mata aimashō.” “Ē, kochira koso.”
English: “Let’s meet again.” “Yes, the pleasure is all mine (It is precisely me, too).”
Example #5
努力と忍耐力でこそ、夢は叶う。
Furigana: どりょくとにんたいりょくでこそ、ゆめはかなう。
Romaji: Doryoku to nintairyoku de koso, yume wa kanau.
English: It is precisely through effort and perseverance that dreams come true.
Example #6
この本にこそ、私が知りたかった情報が書かれている。
Furigana: このほんにこそ、わたしがしりたかったじょうほうがかかれている。
Romaji: Kono hon ni koso, watashi ga shiritakatta jōhō ga kakareteiru.
English: It is precisely in this book that the information I wanted to know is written.
Example #7
若くて失敗を恐れないからこそ、新しいことに挑戦できる。
Furigana: わかくてしっぱいをおそれないからこそ、あたらしいことにちょうせんできる。
Romaji: Wakakute shippai o osorenai kara koso, atarashii koto ni chōsen dekiru.
English: It is precisely because one is young and unafraid of failure that one can challenge new things.
Example #8
忙しい日々を送っているあなただからこそ、休息が必要だ。
Furigana: いそがしいひびをおくっているあなただからこそ、きゅうそくがひつようだ。
Romaji: Isogashii hibi o okutte iru anata da kara koso, kyūsoku ga hitsuyō da.
English: It is precisely because you lead busy days that you need rest.
Example #9
他の誰でもない、彼にこそこの仕事を任せたい。
Furigana: ほかのだれでもない、かれにこそこのしごとをまかせたい。
Romaji: Hoka no dare demo nai, kare ni koso kono shigoto o makasetai.
English: Not anyone else, but precisely him is who I want to entrust this job to.
Example #10
厳しいトレーニングを経てこそ、真の力が身につく。
Furigana: きびしいトレーニングをへてこそ、しんのちからがみにつく。
Romaji: Kibishii torēningu o hete koso, shin no chikara ga mi ni tsuku.
English: It is only after undergoing strict training that one acquires true strength.
Notes & Nuances
📌 Important Points
Replacement of Particles
When こそ emphasizes a Noun, it often replaces topic or subject particles (は/が). It can follow other particles like に (e.g., 君にこそ伝えたい).
Example: 今こそ、チャンスだ。 (Ima koso, chansu da.)
The Powerful Combination: からこそ
When combined with から, it means “It is precisely because X is true that Y happens,” strongly connecting cause and effect, often implying that X is a necessary condition.
Example: 健康だからこそ、仕事ができるのだ。(Kenkou da kara koso, shigoto ga dekiru no da.)
Conditional Nuance with V-てこそ
When used with the て form or verb stem, it often means “Only after/by doing X does Y have meaning/is possible.” This usage is slightly more formal and is often translated as “only when…” or “it is by…”
Example: 勝ってこそ、意味がある。(Katte koso, imi ga aru.)
⚠️ Common Mistakes
❌ Using こそ when simple topic/subject particles (は/が) suffice.
✅ Use は or が for general topics or simple contrast. Use こそ only when extreme, exclusive emphasis is necessary.
こそ has a very strong exclusive nuance. Overusing it can make your speech sound unnatural or overly dramatic if the emphasis isn’t warranted.
❌ Attaching こそ directly to a verb stem (e.g., 勉強こそ).
✅ Attach こそ only after から (or sometimes after the te-form or verb stem followed by a particle) to emphasize the condition.
In most cases, こそ does not attach directly to a verb or adjective stem; it needs to follow a particle or a fully defined phrase (like Noun, or Clause + から).
🏛️ Cultural Context
Politeness Level: Neutral to Polite. While the particle itself is neutral, its use in set phrases (こちらこそ, ありがとうこそ) is highly polite and appropriate for formal and semi-formal interactions.
Social Situations: Used when accepting praise or expressing mutual gratitude (こちらこそ) and when expressing strong conviction about a specific factor (e.g., in debates or presentations).
Regional Variations: Standard Japanese. No significant regional variations in meaning or usage.
🔍 Subtle Differences
こそ vs. は (wa)
は introduces a topic or provides general contrast. こそ asserts a strong, singular focus, often implying that other possibilities are excluded.
When to use: Use こそ when you want to highlight one specific item as *the* factor/reason/time. Use は for general conversational flow.
こそ vs. だけ (dake)
だけ means “only/just,” focusing on quantity or limitation. こそ focuses on quality or importance, emphasizing that something is the *most* appropriate or *essential* element.
When to use: Use だけ when limiting the scope (e.g., Only students). Use こそ when stressing importance (e.g., Precisely the teacher).
📝 Conjugation Notes
こそ is an emphasis particle (係助詞). It does not conjugate itself, but the word or phrase it follows must be in the appropriate form, typically Noun, or a Clause ending in Plain Form + Particle (most commonly から). The final verb of the clause containing こそ is *not* required to be in the polite ます form.
🔊 Pronunciation Tips
Pronounce こそ with a slight emphasis on the syllable immediately preceding it, followed by a clear, assertive delivery of こそ to maximize the emphatic effect.
🧠 Memory Tips
Relate こそ to the English phrase “It is precisely…” or the Spanish “solo.” The two hiragana characters (こ and そ) look like two arrows pointing strongly at the preceding word, signifying exclusive focus.
Other Grammar
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