～てこそ
Only if, Because, By, Unless, Until
Structure
Explanation
Building on the particle こそ, which emphasizes something as the 'very' reason, attaching it to the て-form of a verb expresses that (B) is entirely conditional upon (A) taking place. This strong condition can be conveyed in English in various ways, with the specific meaning often clarified by the context of (B). Common translations are 'only after (A), then (B)', 'not until (A) can (B)', and 'it is precisely by doing (A) that (B)'.
- 病気になってこそ、健康のありがたさが分かる。It is only after getting sick that you understand the value of good health.
- 一人で暮らしてこそ、家族の大切さがわかる。Only by living alone can you truly appreciate your family.
- 毎日練習してこそ、ピアノが上手になる。You can become skilled at the piano only if you practice every day.
- みんなで協力してこそ、この仕事は終わる。This project will get finished only if everyone cooperates.
While the English translation may vary, the core function is to show that condition (A) is the sole determining factor for the result or realization expressed in (B). This structure is frequently used to express a strong personal conviction, a lesson learned from experience, or a subjective judgment about how things ought to be.
Examples
毎日努力してこそ、夢は叶うものだ。
Only by working hard every day can one's dreams come true.
苦しい時に支え合ってこその夫婦でしょう。
A married couple is defined only by supporting each other during difficult times, don't you think? (only because)
実際に使ってみてこそ、このツールの便利さが実感できる。
Only by actually using it can you truly appreciate how convenient this tool is.
健康であってこそ、仕事も勉強もできる。
Only if you are healthy can you work and study. (only because)
困難な状況を乗り越えてこそ、人は強くなる。
A person becomes strong only by overcoming difficult situations.
お互いに信頼してこそ、いい関係が築ける。
You can build a good relationship only by trusting each other.
厳しい訓練を積んでこそ、プロの選手になれるのだ。
It's only by undergoing rigorous training that one can become a professional athlete. (until/unless)
長年住んでこそ、その町の本当の良さが味わえる。
You can appreciate the true charm of a town only by living there for many years.
安全が確保されてこその楽しいイベントだ。
It's a fun event only if safety is guaranteed. (only because)
最後まであきらめないでこそ、チャンスはやって来る。
Opportunity will present itself only if you don't give up until the very end.
人に教えてこそ、自分の理解が深まる。
Only by teaching others does one's own understanding deepen.
苦労してこそ、得られる喜びがある。
There is a joy that can be obtained only by struggling.