もしそうならMeanings1expressionif so; in that caseA conditional phrase used to introduce a consequence or question based on a preceding statement. Common in both spoken and written Japanese.もしそうなら、すぐに出しゅっ発ぱつしましょう。If so, let's leave right away.もしそうなら、なぜ教おしえてくれなかったの?If that's the case, why didn't you tell me?