GRAMMAR DETAIL

てこそ

only by · only when

Emphasizes that a value or result can arise only when the preceding condition is fulfilled.

Examples

困難を乗り越えてこそ、本当の自信が生まれる。

Only by overcoming difficulties can true confidence develop.

毎日続けてこそ、力が身につく。

Only by keeping at it every day can you truly develop your skills.

Structure: Attach こそ to a verb's te-form to emphasize the preceding action as a key condition for the value or result that follows.
Basic usage: 毎日続けてこそ、力が身につく。 presents daily persistence as an essential condition for developing skill.

Sequence versus condition
- 練習してから発表する gives the sequence of practicing and then presenting. 練習してこそ上達する emphasizes practice as the condition that makes improvement possible.
Position of こそ
- Place it immediately after the te-form, as in 乗り越えてこそ. Moving it to 困難こそ shifts the focus from overcoming difficulties as a condition to the noun meaning difficulties.