〜こそ: Emphasis ('It Is Precisely...')
What it means
こそ adds emphasis to whatever comes directly before it. It singles that word out and says, in effect, "this one, above all others." English reaches for words like precisely, exactly, the very, for sure — or just heavy stress on the word.
It does not change the grammar of the sentence; it simply highlights one element. Most often that element is a noun (or a noun-like phrase).
今度こそ合格する。
こんどこそ ごうかくする。
This time for sure, I'll pass.
今度こそ = this time (and not the previous failures).
こちらこそ、よろしくお願いします。
こちらこそ、よろしく おねがいします。
No, the pleasure is mine.
A set reply: 'It is I who should be saying that.'
ヤッタンは、今日こそ宿題をやると言った。
ヤッタンは、きょうこそ しゅくだいを やると いった。
Yattan said that today, for real, he'd do his homework.
How to form it
こそ attaches after the word you want to stress. With a plain noun it just follows it. It can also stack onto certain particles — most importantly から (giving からこそ).
| Pattern | Formation | Example |
|---|---|---|
| Noun + こそ | noun + こそ | 今度こそ (this time for sure) |
| Set phrase | こちら + こそ | こちらこそ (the same to you / mine) |
| Reason: からこそ | plain clause + からこそ | 努力したからこそ (precisely because I worked hard) |
| With を/が dropped | the topic-marked element + こそ | 君こそ (you, of all people) |
Note that when こそ attaches to a subject or object, the particles が and を usually drop: 君こそ (not 君がこそ), あなたの応援こそ (not を). から does not drop — it fuses into からこそ.
More examples
モチがいたからこそ、ヤッタンは試験を乗り越えられた。
モチが いたからこそ、ヤッタンは しけんを のりこえられた。
It was precisely because Mochi was there that Yattan got through the exam.
からこそ = precisely because — a stronger, more emphatic から.
先生、ご指導ありがとうございました。
せんせい、ごしどう ありがとうございました。
Teacher, thank you for your guidance.
A natural lead-in to the next reply.
いいえ、こちらこそ。よく頑張りましたね。
いいえ、こちらこそ。よく がんばりましたね。
No, the thanks are mine. You worked really hard.
弟こそ、本当のヒーローだ。
おとうとこそ、ほんとうの ヒーローだ。
My little brother is the real hero.
弟こそ = my brother, of all people — singling him out.
からこそ — "precisely because"
から already means "because." Adding こそ makes the reason emphatic: it's not just a reason, it's the very reason. Use it when you want to insist that this cause — and nothing else — is what made the difference.
難しいからこそ、挑戦する価値がある。
むずかしいからこそ、ちょうせんする かちが ある。
It's precisely because it's hard that it's worth taking on.
A からこそ clause is often followed by のだ／んだ (難しいからこそ挑戦するんだ) to drive the emphasis home, though it isn't required.
A quick note on 〜てこそ
You may also meet 〜てこそ ("only by doing… / it's only when you do…"): 努力してこそ成功できる ("only through real effort can you succeed"). That is a separate pattern — verb て-form + こそ — and we cover it in its own guide. For now, just recognize that てこそ stresses a condition for an action, while plain noun + こそ and からこそ stress a thing or a reason.
Common mistakes
- Forgetting that こそ marks the word right before it. こそ emphasizes whatever it touches, so placement matters: 今日こそやる ("today for sure I'll do it") vs. 宿題こそやる ("the homework is the thing I'll do"). Put it on the word you mean to spotlight.
- Keeping が or を before こそ. When the emphasized element is a subject or object, drop the particle: 君こそ正しい (✓), not 君がこそ. With から, though, you keep it: からこそ.
- Using plain から when you want emphasis. 努力したから成功した just states a reason; 努力したからこそ成功した insists it was precisely that reason. Reach for からこそ only when you want that punch.
- Confusing こそ with 〜てこそ. Noun + こそ / からこそ emphasize a thing or a cause. 〜てこそ ("only by doing") attaches to a verb's て-form and is a different point.
Quick recap
- こそ spotlights the word before it = "precisely / exactly / the very."
- Common with nouns: 今度こそ (this time for sure), こちらこそ (the same to you).
- からこそ = "precisely because" — an emphatic version of から.
- Drop が／を before こそ; keep から (→ からこそ).
- 〜てこそ ("only by doing") is a related but separate pattern.
Your turn
Choose where こそ / からこそ belongs to add the right emphasis.
Start the 5-question drill →Frequently asked questions
What does こそ actually add to a sentence?
It emphasizes the word right before it — 'precisely,' 'exactly,' 'the very one.' 今度こそ合格する means 'this time, for sure, I'll pass,' contrasting with past failures.
What's the difference between から and からこそ?
から just gives a reason ('because'). からこそ insists it's the decisive reason ('precisely because'): 努力したからこそ成功した = 'it was exactly because I worked hard that I succeeded.'
Do I keep が or を before こそ?
No. When こそ attaches to a subject or object, the が or を drops: 君こそ正しい, not 君がこそ. But から stays and fuses into からこそ.
Is こそ the same as 〜てこそ?
No. Noun + こそ and からこそ emphasize a thing or a reason. 〜てこそ ('only by doing') attaches to a verb's て-form and stresses a condition for an action — it's a separate grammar point.
What does こちらこそ mean?
It's a set reply meaning 'the same to you' or 'it's I who should be saying that.' When someone thanks you or says よろしく, こちらこそ returns the sentiment with emphasis.