Translation guide
The English phrase 'red line' can refer to a literal red-colored line, a boundary or limit that should not be crossed, or a specific policy or principle that is non-negotiable. This guide helps learners express these concepts naturally in Japanese.
Referring to a physical line that is red in color, such as on a map, document, or surface.
The most direct translation for a literal red line. Use this for any physical red line.
Please draw a red line on the map.
A compound noun meaning 'red line'. Often used in contexts like editing, marking, or indicating boundaries on documents.
I drew a red line at the corrections.
A point beyond which one should not go; a limit that, if crossed, will trigger serious consequences.
Literally 'a line that must not be crossed'. This is a natural way to express a red line in a figurative sense, emphasizing a strict boundary.
That is a red line that must not be crossed.
A loanword from English, used in political, diplomatic, or business contexts to mean a non-negotiable limit. Common in news and formal discussions.
Means 'boundary line' or 'limit line'. Can be used in technical or formal contexts, but less common for figurative red lines.
We clarified the red line in the negotiations.
A firm stance or rule that will not be compromised, often used in politics, business, or personal values.
While '赤い線' is correct for a physical red line, using it for a figurative boundary can sound unnatural. Use phrases like '越えてはならない一線' or 'レッドライン' instead.
That is a red line.
The government regards that issue as a red line.
Privacy is a red line that must be absolutely protected.