～てこそ

When to use

てこそ: only by doing X (やってこそ分かる).

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).

• 勉強べんきょうしてこそ、テストに合格ごうかくできる。

  Only when you study can you pass the test.

  Benkyō shite koso, tesuto ni gōkaku dekiru.

• 素直すなおになってこそ、相手あいての気持きもちが分わかります。

  Only when you’re honest can you understand the other person’s feelings.

  Sunao ni natte koso, aite no kimochi ga wakarimasu.

• 静しずかでこそ、心こころが落おち着つく。

  Only in silence can one’s mind be at peace.

  Shizuka de koso, kokoro ga ochitsuku.

• 友達ともだちでこそ、お互たがいに助たすけ合あうのは当然とうぜんだ。

  Precisely because we’re friends, it’s natural to help each other.

  Tomodachi de koso, otagai ni tasukeau no wa tōzen da.

Emphasis With こそ (Precisely / Only By)

• ～こそ〜kosoN3Emphasizes the importance or uniqueness of something or…
• ～からこそ〜kara kosoN2Express the emphasis on the reason; 'precisely because'…
• Noun こそあれ~koso areN1Expresses 'though there is ... (some negative or…
• Noun こそ～が~koso~gaN1Emphasizes that 'it is precisely Noun that ...', then adds…
• Noun こそすれ~koso sureN1An emphatic pattern meaning 'it may be X, but definitely…
• Verb こそすれ~koso sureN1Often used in the pattern 'Xこそすれ、Y〜ない', meaning 'One might…

Compare when to use each