At a glance
～とあれば means "if it is the case that ~". It is used when a special or important condition makes the speaker willing, or obliged, to do something.
[Noun / Plain form] とあれば、[willing action or necessity]
必要とあれば、すぐに行きます。 If it's necessary, I'll go right away.
How to form it
| Attaches to | Form | Example |
|---|---|---|
| Verb | Plain form | 来るとあれば / 来ないとあれば |
| い-adjective | Plain form | 安いとあれば |
| な-adjective | Stem, usually without だ | 必要とあれば |
| Noun | Noun, usually without だ | 子供のためとあれば |
Register: formal. It is mostly used in writing and formal speech.