Translation guide
How to express that something is widely known or obvious in Japanese, from neutral facts to idiomatic phrases.
To say that something is generally known by most people.
A neutral, common phrase meaning 'a widely known fact'. Suitable for both spoken and written contexts.
That is common knowledge.
Means 'common sense' or 'common knowledge'. Often used for things that everyone is expected to know.
That's common knowledge.
Literally 'everyone knows'. A straightforward, conversational way to say something is common knowledge.
Everyone knows that story.
To emphasize that something is so obvious it doesn't need to be stated.
Means 'it goes without saying' or 'needless to say'. Very common in both speech and writing.
Needless to say, health is important.
Means 'obvious', 'natural', or 'a matter of course'. Very common in casual conversation.
An idiomatic expression meaning 'as clear as day' or 'obvious'. Literally 'clearer than seeing fire'. Used for emphasis.
To use a set phrase or proverb to express that something is universally known.
A proverb meaning 'everyone knows except the husband', used when something is widely known but the person most concerned is unaware. Equivalent to 'it's an open secret'.
His affair is an open secret.
常識 implies something that should be known as part of basic social knowledge, while 周知の事実 simply states that a fact is widely known without the normative nuance.
It's common sense not to be late.
It's common knowledge that he quit.
The direct translation '共通の知識' is not natural Japanese and should be avoided. Use the phrases above instead.
That's a matter of course.
It's obvious that he is lying.