Translation guide
In Japanese, expressing 'old friendship' depends on whether you're referring to the relationship itself, the person who is an old friend, or the nostalgic feeling of a long-standing bond. The most natural expressions often use words like 昔 (old times) or 長い (long) combined with 友達 (friend) or 付き合い (relationship).
Referring to a person you have been friends with for a long time.
Literally 'friend from long ago'. This is the most common and natural way to refer to an old friend.
He is an old friend.
A slightly formal or literary term for an old friend. Often used in writing or formal speech.
I reunited with an old friend.
Emphasizes the long duration of the friendship. 'Friend of many years'.
She is a friend of many years.
Specifically a childhood friend, someone you've known since you were young. Not exactly 'old friendship' but related.
He is my childhood friend.
Referring to the relationship or bond itself that has lasted a long time.
Literally 'long association/relationship'. This is the most natural way to describe a long-standing friendship or acquaintance.
We have a long-standing friendship.
Similar to 長い付き合い, but emphasizes that the relationship dates back to old times.
I've known him for a long time (our relationship goes way back).
A formal, literary term for old friendship. Often used in phrases like 旧交を温める (renew an old friendship).
Expressing the sentimental or nostalgic feeling associated with an old friendship.
Literally 'old friendship'. This directly translates the concept and is used when talking about the friendship itself in a nostalgic context.
I remember our old friendship.
Emphasizes the nostalgic feeling. 'Nostalgic friendship'.
The nostalgic friendship came back to me.
友達 (ともだち) is the most common word for 'friend'. 友人 (ゆうじん) is slightly more formal. 仲間 (なかま) means 'companion' or 'colleague' and implies a shared activity or group, not necessarily a deep personal friendship. For 'old friendship', 友達 is usually best unless the context is formal.
He is a friend from my university days. (formal)
The direct translation '古い友情' (ふるいゆうじょう) is not idiomatic. '古い' usually means 'old' in the sense of 'not new' or 'aged', and sounds unnatural for friendships. Use 昔の友情 or 長い付き合い instead.
Our old friendship means a lot to me.
He is an old friend from high school.
高校時代 (high school days) + からの (from) + 昔からの友達 (old friend). You can also say 高校時代の友達 (a friend from high school days).
旧交を温める。
To renew an old friendship.