9.6 Obligation

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Overview

Japanese expresses obligation ("must / have to") by combining a negative conditional form with a word meaning "it won't do." The tone ranges from formal (～なければなりません) to casual contractions like ～なきゃ and ～なくちゃ.

Obligation and necessity — “must / have to”

The general pattern for expressing obligation or necessity to do something (“you must do …”, “you have to do …”) is:

Some sort of negative conditional form followed by a verb that expresses something in terms of “it won't work” or “it won't do”.

Conditional form	Possible endings	Politeness / tone	Notes
～なければ	いけない / ならない / だめ	neutral → formal	Standard form
～なくては	いけない / ならない / だめ	neutral → formal
～ないと	いけない / ならない / だめ / Ø	casual → neutral
～なきゃ	いけない / だめ / Ø	casual	Shortened なければ
～なくちゃ	いけない / だめ / Ø	casual	Shortened なくては

Ø = ending omitted (very common in casual speech)

～なきゃ and ～なくちゃ are spoken contractions of ～なければ and ～なくては.

Ending	Tone	Typical usage
なりません	Polite–formal	Polite rules, announcements, writing
ならない	Formal, strict	Rules, instructions, written language
いけません	Polite	Polite speech, everyday situations
いけない	Neutral, conversational	Most common in everyday speech
だめ	Direct, blunt	Casual speech, strong obligation
Ø (omitted)	Very casual	Spoken language when meaning is obvious

Examples by style

Neutral / polite

。

I have to do my homework.

。

This document must be submitted.

Casual speech

。

I have to go now.

、。

I have to sleep, since tomorrow’s early.

。

I’ve got to take my medicine.

Omitting いけない / ならない is common in casual speech when the meaning is obvious.

～いけない vs ～ならない

いけない
- Softer, more conversational
- Common in everyday speech
ならない
- Stronger, more formal
- Common in rules, instructions, writing

。

Smoking here is not allowed.

Points to keep in mind

All forms express obligation or necessity; differences are mostly tone and formality
なきゃ / なくちゃ are casual contractions
Endings are often dropped in casual speech

Dialogue

あす明日はじゅぎょう授業があるから、はやく早くおきなければ起きなければなりません。しゅくだい宿題はきょうじゅうに今日中にていしゅつ提出しなければいけません。しけん試験のまえ前に、もっとふくしゅう復習しなければならないとおもいます思います。せいふく制服をきなければ着なければいけないので、まいあさ毎朝じゅんび準備がたいへん大変です。もうおそい遅いから、そろそろかえらない帰らないといけない。あす明日はやい早いから、こんや今夜ははやく早くねなきゃ寝なきゃ。くすり薬をのまなくちゃ飲まなくちゃとおもっている思っているけど、わすれてしまいました忘れてしまいました。このしょるい書類はあす明日までにていしゅつ提出しなければなりません。しゅうまつ週末もしごと仕事しなきゃいけないかもしれない。としょかん図書館のほん本はらいしゅう来週までにかえさなければ返さなければいけません。あさごはん朝ごはんをちゃんとたべなくちゃ食べなくちゃ、からだ体にわるい悪いよ。ぱすぽうとパスポートをこうしん更新しなければならないのに、じかん時間がなくてこまっています困っています。

I have class tomorrow, so I must wake up early. The homework must be submitted by today. I think I have to review more before the exam. Because I have to wear a uniform, getting ready every morning is tough. It's already late, so I have to head home soon. I have an early start tomorrow, so I've got to go to bed early tonight. I know I need to take my medicine, but I keep forgetting. This document must be submitted by tomorrow. I might have to work on the weekend too. The library books have to be returned by next week. You've got to eat breakfast properly — it's bad for you otherwise. I need to renew my passport, but I'm troubled because I have no time.

9.5 Advice and regret

9.7 Even if

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