At a glance
～となれば means "if it comes to ~" or "if it's the case that ~". The speaker treats a situation as real or likely, then states what naturally follows: a judgment, a decision, or something that must be done.
Verb / い-adj (plain form) + となれば
Noun / な-adj stem + となれば
海外に行くとなれば、パスポートが必要だ。 If you're going abroad, you'll need a passport.
How to form it
となれば is と (the と of ～となる) plus なれば (the ば-conditional of なる, "to become").
| Attaches to | Form | Example |
|---|---|---|
| Verb | Plain form (present, negative, past) | 行くとなれば / 行かないとなれば / 決まったとなれば |
| い-adjective | Plain form | 高いとなれば |
| な-adjective | Stem (+である in formal writing) | 必要となれば |
| Noun | Noun (+である in formal writing) | 雨となれば |
となれば is used in both speech and writing. The end of the sentence sets the politeness level.