Start with a question:
日本へ留学に行く＿＿お金を貯めています。
A. ように B. ために C. のに D. から
The answer is B. ために. "I'm saving money in order to study in Japan" -- here ために expresses purpose.
But ために has another face. Look at this:
雨があまり降らなかったために水不足になった。 "Because it didn't rain much, there was a water shortage."
Same word, but here it expresses reason. How do you tell them apart?
The Key: Can You Decide to Do It?
| Purpose (in order to) | Reason (because of) | |
|---|---|---|
| Preceding clause | Volitional verb (something you can decide to do) | Non-volitional verb / state |
| Meaning | In order to achieve a goal | Due to a cause, leading to a result |
| Example | 留学するために貯める | 雨が降らなかったために不足になった |
Core rule: If you can decide to do it, it's purpose. If you can't control it, it's reason.
Use 1: Purpose (In Order To)
Preceded by a volitional verb (an action you can decide to take) or noun + の:
-
日本へ留学に行くためにお金を貯めています。 → I'm saving money in order to study in Japan.
-
良い将来のために一生懸命勉強している。 → I'm studying hard for a bright future.
-
出世するためにたくさん勉強している。 → I'm studying a lot in order to get ahead in my career.
-
家族のために働いている。 → I'm working for my family's sake.
ために vs ように (Purpose)
Both can express purpose. The difference lies in verb type:
| ために | ように | |
|---|---|---|
| Pairs with | Volitional verb (dictionary form) | Non-volitional verb / potential form |
| Example | 合格するために勉強する | 合格できるように勉強する |
| Feeling | Study in order to pass (direct goal) | Study so that I can pass (indirect goal) |
Simple rule: ために pairs with "things you can do"; ように pairs with "things you may or may not be able to do."
Use 2: Reason (Because Of)
Preceded by a non-volitional verb (natural phenomena, state changes, things beyond your control):
-
雨があまり降らなかったために水不足になった。 → Because it didn't rain much, there was a water shortage.
-
事故があったために電車が遅れた。 → Because there was an accident, the train was delayed.
-
台風のために学校が休みになった。 → Because of the typhoon, school was cancelled.
ために vs ので / から (Reason)
All three express reason, but with different registers:
| ために | ので | から | |
|---|---|---|---|
| Formality | Written / formal | Neutral | Casual |
| Feeling | Due to... resulting in | Because... | Because... |
| Restriction | Usually non-volitional | No special restriction | No special restriction |
ために as a reason is more formal and written. In everyday conversation, ので or から are more common.
Noun + のために
When a noun precedes ために, add の:
| Example | Use |
|---|---|
| 家族のために働く。 | Purpose: for my family |
| 台風のために休みになった。 | Reason: because of the typhoon |
Noun + のために can mean either purpose or reason -- context tells you which.
Self-Test
Q1. Is ために in 「試験に合格するために毎日勉強している」 purpose or reason?
Show answer
Purpose. 「合格する」is a volitional verb (you can decide to work toward passing), so ために means "in order to pass the exam."
Q2. Is ために in 「電車が止まったために会社に遅刻した」 purpose or reason?
Show answer
Reason. 「電車が止まった」is not something you can control (non-volitional), so ために means "because the train stopped, I was late."
Q3. Is 「日本語が話せるために毎日練習する」 correct?
Show answer
It sounds unnatural. 「話せる」is potential form (non-volitional), so you should use ように: 日本語が話せるように毎日練習する. ために pairs with volitional verbs; ように pairs with non-volitional / potential forms.
Summary
- Volitional verb + ために = purpose (in order to)
- Non-volitional verb + ために = reason (because of)
- Deciding factor: can you control the preceding action? Yes = purpose; No = reason
- Nouns need の: 家族のために
- For purpose: distinguish from ように (ために = volitional, ように = non-volitional/potential)
- For reason: more formal/written than ので and から