Prohibition: ～てはいけません
Verb-て + は いけません
Verb-て + は いけません = it's forbidden. Softer: ～ないでください. Casual speech: ～ちゃ だめ.
In short
～てはいけません = “you must not…, it's forbidden”. ここで たばこを すっては いけません (smoking is not allowed here). It's the negative answer to ～てもいいですか.
- ここで しゃしんを とっては いけません。koko de shashin o totte wa ikemasenTaking photos is not allowed here.
- としょかんで たべては いけません。toshokan de tabete wa ikemasenNo eating in the library.
- しけんで じしょを つかっては いけません。shiken de jisho o tsukatte wa ikemasenDictionaries are not allowed in the exam.
The basics
て-form + は いけません = “if you do…, it's not OK”: it's a prohibition. You read it on signs and in rules, or hear it from a teacher.
- ここで たばこを すっては いけません。koko de tabako o sutte wa ikemasenSmoking is not allowed here.
- としょかんで 食べては いけません。toshokan de tabete wa ikemasenNo eating in the library.
A firm prohibition
～てはいけません is categorical: it's a rule, not a request. To kindly ask someone not to do something, people prefer ～ないでください (covered on the next line).
| Phrase | Nuance |
|---|---|
| ～てはいけません | it's forbidden (a rule) |
| ～ないでください | please don't… (a polite request) |
| ～てもいいです | it's allowed |
In speech: ちゃだめ
Between friends or to a child, ては contracts to ちゃ and いけません becomes だめ: 食べちゃ だめ (hands off, don't eat that). You'll hear it in anime.
Answering a request for permission
To “～ても いいですか”, a flat no uses ～ては いけません, but it's harsh. You soften it with すみません.
- すみません、ここに 車を とめては いけません。sumimasen, koko ni kuruma o tomete wa ikemasenSorry, you can't park here.
Common mistakes
- Reading ては as “te-ha”: は is a particle, you say “te wa”.
- Using ～てはいけません for a simple request: it's a prohibition, it can sound bossy.
- Forgetting は: ～ていけません doesn't express prohibition.
5 exercises on this point
Particles to choose, sentences to put back in order, translations: marked straight away, then reviewed at the right time. This JLPT N5 point is on the Yamanote Line (The て-form) of the Tokyo subway.