Translation guide
The adverb 'mutually' describes a reciprocal relationship where two or more parties do or feel the same thing toward each other. In Japanese, this is most often expressed with the adverb お互いに (otagai ni), but other patterns like 相互 (sōgo) or verb endings can also convey reciprocity.
Expressing that two or more people do the same thing to or feel the same way about each other.
The most common and versatile way to say 'mutually'. It can be used with verbs, adjectives, or nouns to indicate a reciprocal relationship.
お互いに is used in everyday conversation for any mutual relationship. 相互に is more formal and often appears in business, academic, or technical writing. For casual speech, stick with お互いに or the verb-合う pattern.
Many English phrases with 'mutually' or 'each other' are best translated with a compound verb ending in 合う. For example, 'help each other' → 助け合う, 'understand each other' → 理解し合う. This pattern is very productive and sounds natural.
私たちはお互いに助け合った。
We helped each other mutually.
お互いに気をつけましょう。
Let's be careful mutually.
More formal and often used in written or technical contexts. It emphasizes a two-way relationship.
両国は相互に協力することを約束した。
The two countries promised to cooperate mutually.
Attach 合う to the stem of a verb to mean 'do mutually'. This is a very natural way to express reciprocal actions.
A slightly more literary or formal version of お互いに. Less common in everyday speech.
互いに信頼することが大切だ。
It is important to trust each other mutually.