Translation guide
The instrumental case expresses the means, tool, or agent by which an action is performed. In Japanese, this is not a grammatical case but is expressed through particles, postpositions, and verb constructions.
Expressing the instrument or means by which an action is carried out.
The particle で marks the means or tool used to perform an action. It is the most common way to express instrumental meaning.
ペンで手紙を書きました。
I wrote a letter with a pen.
バスで学校に行きます。
I go to school by bus.
The te-form of 使う (to use) explicitly states 'using N'. It is slightly more emphatic than で.
コンピューターを使って資料を作ります。
I make materials using a computer.
A formal/literary pattern meaning 'by means of' or 'through'. Often used in written or academic contexts.
この問題は話し合いによって解決された。
This problem was solved through discussion.
Indicating the agent or cause in a passive sentence.
In passive sentences, に marks the agent (the doer) of the action. This corresponds to 'by' in English instrumental passives.
犬にかまれました。
I was bitten by a dog.
先生に褒められました。
I was praised by the teacher.
In formal passive constructions, によって can mark the agent, especially with inanimate or abstract agents.
その建物は有名な建築家によって設計された。
The building was designed by a famous architect.
Expressing the cause or reason for a state or action, often corresponding to instrumental 'by' or 'with' in English.
で can also mark the cause of an event or state, similar to 'due to' or 'because of'.
台風で電車が止まりました。
The trains stopped due to the typhoon.
病気で学校を休みました。
I was absent from school because of illness.
ために explicitly states the cause or reason, often used for negative outcomes.
雨のために試合が中止になった。
The game was canceled due to rain.
Describing the manner or state in which an action is performed, often corresponding to English adverbs or 'with' phrases.
で can also indicate the manner or state, often with nouns describing conditions or attitudes.
大声で話さないでください。
Please don't speak in a loud voice.
一人で映画を見ました。
I watched a movie by myself (alone).
In some adverbial expressions, に marks manner, often with onomatopoeic or mimetic words.
ぴかぴかに磨く。
Polish until shiny.
Expressing doing something together with someone, corresponding to 'with' in English.
The particle と marks the person or entity with whom an action is performed.
友達と遊びました。
I played with my friend.
一緒に emphasizes doing something together.
家族と一緒に旅行に行きます。
I will go on a trip with my family.
Both express means, but で is more concise and natural in everyday speech. を使って is more explicit and can be used when the tool is not obvious or needs emphasis.
はしで食べます。
I eat with chopsticks.
特別な道具を使って修理しました。
I repaired it using a special tool.
Japanese does not have an instrumental case. Learners should focus on the particles and patterns that convey the intended meaning rather than trying to map case labels directly.