～てこそ (〜te koso)
Explanation
Emphasizes the condition; 'only when', 'precisely because'.
Formation
Verb-て form + こそ / い-Adjective + くてこそ / な-Adjective + でこそ / Noun + でこそ
Detailed Explanation
The ～てこそ grammar point is used to emphasize that 'only when' or 'precisely because' the stated condition is met, a certain result or meaning arises. For nouns and adjectives, similar forms appear (e.g., Noun + でこそ, い-Adjective くてこそ, な-Adjective でこそ).
Examples
勉強してこそ、テストに合格できる。
Benkyō shite koso, tesuto ni gōkaku dekiru.
Only when you study can you pass the test.
素直になってこそ、相手の気持ちが分かります。
Sunao ni natte koso, aite no kimochi ga wakarimasu.
Only when you’re honest can you understand the other person’s feelings.
静かでこそ、心が落ち着く。
Shizuka de koso, kokoro ga ochitsuku.
Only in silence can one’s mind be at peace.
友達でこそ、お互いに助け合うのは当然だ。
Tomodachi de koso, otagai ni tasukeau no wa tōzen da.
Precisely because we’re friends, it’s natural to help each other.
Grammar content sourced from hanabira.org.