Translation guide
A guide to expressing the English phrase 'as long as' in Japanese, covering its two main uses: stating a condition ('provided that') and expressing duration ('for the entire time that').
Expressing a condition that must be met for something to happen or be true, similar to 'if and only if' or 'on the condition that'.
Attach to the ば conditional form of a verb. Emphasizes that as long as that action is done, the result will follow. Often used for minimal conditions.
努力さえすれば、成功できる。
As long as you make an effort, you can succeed.
Attach to the dictionary form of a verb or adjective. Means 'as long as' in the sense of 'while a certain state continues'. Often used for conditions that are ongoing.
ここにいる限り、安全だ。
As long as you are here, you are safe.
The simple conditional form. Can mean 'as long as' when context implies a sufficient condition, but is less emphatic than さえすれば.
安ければ、買います。
As long as it's cheap, I'll buy it.
Emphasizes a continuous state or action as the condition. Similar to 'as long as one is doing'.
笑ってさえいれば、幸せになれる。
As long as you keep smiling, you can be happy.
Expressing that something happens or is true during the whole time that another action or state continues.
Attach to the dictionary form of a verb or noun + の. Means 'while' or 'during the time that'. Can be used for both 'as long as' and 'while'.
日本にいる間、日本語を勉強します。
As long as I'm in Japan, I'll study Japanese.
Also used for duration, emphasizing the continuation of a state. Often interchangeable with 間 but can sound more formal or emphatic.
生きている限り、希望がある。
As long as you live, there is hope.
Means 'while' or 'as long as' with a nuance of 'while the situation lasts'. Often used for temporary states or opportunities.
若いうちは、いろいろ経験したほうがいい。
As long as you're young, you should experience various things.
〜間 (aida) simply means 'during the time that', while 〜うちに (uchi ni) implies 'while a certain state holds, before it changes'. For 'as long as' in the duration sense, 〜間 is more direct. 〜うちに often translates as 'while' with a sense of urgency.
日本にいる間に、富士山に登りたい。
While I'm in Japan, I want to climb Mt. Fuji.
明るいうちに帰ろう。
Let's go home while it's still light.
The phrase '長い間' (nagai aida) means 'for a long time', not 'as long as'. It cannot be used to express conditions or duration in the sense of 'as long as'.