いち 一道 いちどう 四十 よんじゅう さん けんであれば
ichito ichidōni fuyonjū sankendeareba

Noun
Da Copula

The "-eba" conditional form ("if/when…") of 一都一道二府四十三県

1. If it were one metropolis, one prefecture, two fu, and forty-three counties.

Ba Conditional