とあれば(Emphatic) if, If it is the case that, As (you wish)

とあれば is a grammar pattern in Japanese that is used as an emphatic version of なら 'if'. It will primarily be used in formal situations, or for literary effect, such as in a novel. It may be translated as 'if (A) is the case, then (B)', or 'should (A) be true, then (B)'.

This is a combination of the case-marking particle と, and the hypothetical form of the う-Verb ある 'to be', あれば.

とあれば will primarily follow nouns, but is occasionally also seen after other structures such as verbs and adjectives when the と is being used as a quotation.

(A) is often some special circumstance or condition that leads to the conclusion or assumption of (B), were (A) to be accurate. As this expression is emphatic, (B) will usually indicate something that must be done, or can't be avoided with structures like しかない, なければならない, ざるを得ない, etc.