にせよ / にしろ

にせよ and にしろ mean "even if" or "granted that": you accept the point and say it changes nothing. They go after the plain form of a verb or an い-adjective, and straight after a noun or a な-adjective.

The two mean the same. にせよ is the stiffer, written one; にしろ turns up more in speech. In everyday conversation にしても or the て-form with も is the usual choice.

A noun or a な-adjective never takes だ before にせよ. In writing it can take である instead.

• × 子供だにせよ → 子供にせよ

Whether A or B

Said twice, A にせよ B にせよ means "whether A or B": the outcome is the same either way. The two halves are opposites or a verb and its negative.

With a question word

After a question word, にせよ means "no matter what, which, who". いずれにせよis a fixed phrase for "in any case".