Translation guide
The English word "reinforcements" can refer to additional troops, extra personnel, or things that strengthen something. This guide covers how to express these ideas naturally in Japanese.
Additional troops or military support sent to strengthen a force.
The most common and direct word for military reinforcements. Used in both historical and modern contexts.
援軍が到着した。
Reinforcements have arrived.
彼らは援軍を要請した。
They requested reinforcements.
Often used in military or police contexts, emphasizing the addition of forces. Slightly more formal than 援軍.
増援部隊が前線に送られた。
Reinforcement troops were sent to the front line.
Can mean reinforcements, but more broadly means support or backing. In military contexts, it implies sending help.
応援を頼む。
We need reinforcements.
Extra people sent to assist in non-military situations, such as work, emergencies, or events.
The most versatile word for extra help or support, from coworkers to emergency services.
忙しいので応援を呼んでください。
We're busy, so please call for reinforcements.
消防の応援が来た。
Firefighter reinforcements arrived.
Specifically means increasing the number of personnel. Often used in business or organizational contexts.
A casual, slightly slangy term for a helper or extra hand, often used in sports or informal work settings.
Things that make an object, structure, or argument stronger.
Used for physical reinforcement (e.g., of a building) or strengthening an argument/team.
壁を補強する必要がある。
The wall needs reinforcements.
彼の証言が我々の主張を補強した。
His testimony provided reinforcements for our argument.
Means strengthening or reinforcement in a broad sense, often used for abilities, systems, or materials.
援軍 is strictly military. 応援 is broader and can be used for any kind of support, including cheering. 増援 is formal and often used in official reports or news.
The English plural 'reinforcements' is often expressed with singular or non-count nouns in Japanese. Avoid directly translating the plural form.
プロジェクトのために増員を要請した。
We requested reinforcements (more staff) for the project.
助っ人が来てくれて助かった。
We were saved when reinforcements (helpers) came.
We need reinforcements in security.