Translation guide
The English word "while" has two main functions: as a conjunction meaning "during the time that" and as a conjunction meaning "although" or "in contrast." Japanese uses different structures for each, and the choice depends on whether the subject stays the same or changes, and whether the action is simultaneous or contrasting.
Expressing that two actions happen at the same time, or one action occurs within the duration of another.
Used when an action takes place during the time another action is in progress. The verb before 間に is in ている form for ongoing actions. The subject can be the same or different.
While I was cooking, he was watching TV.
I'll go shopping while the kids are sleeping.
Similar to 間に, but implies taking advantage of a limited time window or doing something before a state changes. Often used for personal opportunities.
I want to travel to various countries while I'm young.
Used when the same person does two actions simultaneously. The verb before ながら is in stem form. The main action is the second verb.
I study while listening to music.
Formal/literary equivalent of ながら. Used in writing or formal speech. Same subject does two actions.
Expressing that two facts are contrasting or that something happens despite an expectation.
Used for contrast or unexpected result. Often carries a nuance of surprise or complaint. The clause before のに is in plain form.
While he eats a lot, he doesn't gain weight at all.
While this apartment is far from the station, the rent is high.
Used for contrast, similar to のに but more formal/literary. Often with も for emphasis. Can be used with adjectives and nouns.
While he is young, he is very reliable.
Used to contrast two different aspects of the same situation or topic. More neutral and often used in writing.
Similar to 一方で, but emphasizes the opposite side of the same thing. Often used for pros and cons.
Expressing that something continues or is valid during a certain condition or period.
Means 'as long as' or 'while' in the sense of a condition that holds. Used with verbs in dictionary form or ている form.
While there is life, there is hope.
While you are here, you are safe.
Literally 'during the period', used to state a condition that applies throughout that time. Often with は for contrast.
While I'm in Japan, let's speak Japanese.
Referring to 'a while' as a length of time.
Both 間に and うちに mean 'while', but うちに often implies a sense of urgency or a limited opportunity ('before it's too late'). 間に is more neutral and simply marks a time window. Use うちに when you want to emphasize doing something before a state changes.
I want to climb Mt. Fuji while I'm in Japan. (neutral)
I want to climb Mt. Fuji while I'm in Japan (before I leave).
ながら can only be used when the same person does both actions. If the subjects are different, use 間に or うちに.
Intended: While I cooked, he watched TV.
While I understand your point, I disagree.
Using が for contrast is natural here.
Please eat it while it's hot.
歩きながら電話しないでください。
Please don't talk on the phone while walking.
While hoping for success, he started a new business.
While it's small, it's a happy home.
While he is kind, he also has a strict side.
While this job pays well, there is a lot of overtime.
While the internet is convenient, it also comes with dangers.
After a while, he came back.
○ 私が料理している間に、彼はテレビを見た。
While I was cooking, he watched TV.