日米 にちべい修好 しゅうこう通商 つうしょう条約 じょうやくだったら
ni chibe ishūkōtsūshōjō yakudattara

Noun
Da Copula

The "-tara" conditional form ("if/when…") of 日米修好通商条約

1. If it had been the Japan-US Treaty of Amity and Commerce; Had it been the Japan-US Treaty of Amity and Commerce

Tara Conditional