Translation guide
Used to say that something should happen or be true according to what is normal, fair, or expected, even if it is not the case in reality.
Expressing that something should be the case based on fairness, norms, or expectations, often implying that reality is different.
A common and natural way to say 'by all rights' or 'originally/normally'. It sets up an expectation that is often contrasted with reality.
本来なら、彼が勝つはずだった。
By all rights, he should have won.
本来なら、もう着いている時間だ。
By all rights, they should have arrived by now.
Literally 'as a matter of course', used to state something that should naturally be the case. Slightly more formal.
当然のことながら、彼はその地位に就くべきだ。
By all rights, he should take that position.
Literally 'speaking from reason', meaning 'by all rights' or 'logically speaking'. Used in more argumentative or explanatory contexts.
道理から言えば、彼女が責任を取るべきだ。
By all rights, she should take responsibility.
本来なら is the most common and versatile, suitable for both spoken and written Japanese. 当然のことながら is more emphatic and formal, often used in writing or speeches to stress that something is naturally expected.
本来なら、もっと早く連絡するべきだった。
By all rights, I should have contacted you sooner.
当然のことながら、規則は守らなければならない。
By all rights, the rules must be followed.
本来なら、彼が謝るべきだ。
By all rights, he should be the one apologizing.
本来なら、こんなことは起こらないはずだ。
By all rights, this shouldn't be happening.