ふりがな付き和文は英文の下にございます。/ The Japanese translation with furigana is below the English text.



1. Three ways to say: "It will be no good!"
2. "Ikemasen"
3. "Dame desu"
4. "Narimasen"
5. Summary

1. Three ways to say: “It will be no good!”

In Japanese, the expressions for obligation (“I must do…”) or necessity (“I need to do…”) are made of two parts.

One part says: “If I don’t/wouldn’t do [something]”, and the other part continues: “It is/it will be/it would be no good!”.

It is a double negative structure, and as a result, it means the equivalent of “I must do [something].” or “I need to do [something].” in English.

In this post, we will focus on the second part.

There are three expressions: “Ikemasen”, “dame desu”, and “narimasen” to fit here. They all mean “it is/will not be good/permitted to do…” but there are slight differences in nuance and usage.

How are they different?

2. “Ikemasen”

“Ikemasen (in the polite style)” or “ikenai (in the plain style)” is, in my opinion, the most popular in conversation. It is also natural in written style.

“Ikemasen” gives the impression that something is not allowed from the speaker’s personal judgment under specific circumstances (not speaking in general).

For example, you can say it with yourself as the subject (see Example 1):

Ex. 1. Watashi wa hachi-ji made ni shigoto ni ikanaito ikemasen. (I have to get to work by eight.)

Also, you can say it with someone else as the subject (Ex. 2):

Ex. 2. [A mother says to her children] O-mise no mono ni sawaccha ikemasen. (You must not touch the things in the store.)

3. “Dame desu”

“Dame desu” (in the polite style) or “dame [da]” (in the plain style) is a much more informal and direct way to say “no good“.

Generally, “dame desu” means doing something is bad, disappointing or unacceptable.

An image to say "ikemasen"
The first word we say to stop a baby from doing something is “dame”.

“Dame” is a versatile adjective and you can use it in many different situations, whereas “ikemasen” and “narimasen” are always used in the “it is not allowed” context.

In the expression for obligation, “dame desu” means “no good” “not allowed”.

Its negative connotation is so strong that you don’t usually use “dame” in a sentence for obligation with yourself as the subject. Compare Ex. 1 in Section 2 and Ex. 3 below:

Ex. 3. Watashi wa hachi-ji made ni shigoto ni ikanaito dame desu. (I have to get to work by eight.)

Of the two, Ex. 1 sounds natural. To hear Ex. 3, we would wonder “What bad things could happen if you would be late? Would they punish you in some way?”

For the same reason, we can use “dame” in a question when we expect an answer such as “Oh, it’s OK. You don’t have to!”.

Ex. 4. [Student] Repooto, ashita made ni dasanakucha dame desu ka? (Do I really have to submit the report by tomorrow?)

   [Teacher] Muzukashikattara, agate demo ii desu yo. (If it’s difficult, you can submit it the day after tomorrow.)

Also, you often use “dame” when you tell your family and friends not to do something. (See Ex. 5)

Ex. 5. [Mother yells at her children:] Abunai! Wataccha dame!! (It’s dangerous! Don’t cross!!)

4. “Narimasen

“Narimasen (in the polite style)” or “naranai (in the plain style)” sounds the most formal of the three expressions for “no good”. It sounds coercive and more formal. And we often use it in writing. 

We feel this way because you see it all the time in legal documents, written rules and regulations, scriptures and so on (Ex. 6). It gives you the impression that someone in authority requires or orders you to do something. You could neglect the requirement or duty or break the rule on pain of some punishment.

Ex. 6. Ken’etsu wa kore o shite wa naranai. Tsuushin no himitsu wa, kore o okashitewa naranai. (No censorship shall be maintained, nor shall the secrecy of any means of communication be violated. Constitution of Japan, Article 21-2) 

Then how does it sound in conversation? 

You can use it with you as the subject as follows:

Ex. 7. Hachi-ji made ni ha-isha ni ikanakereba narimasen. (I must go to the dentist by eight.)

This sounds more formal than “ikemasen” (Ex. 1), but it’s still natural. It is because you sound more objective by using the coercive expression on the obligation you place on yourself.

If, however, you use it in a sentence with someone else as the subject, it sounds as if you spoke as an authority. It’s fine if that’s your intention, but if not, and you use it simply as a replacement for “ikemasen” or “dame”, it sounds stilted, old-fashioned and awkward.

5. Summary

Note: In this table for summary, “a first-person subject” means when you say “I have to do…”, and “a second-person subject” means when you say “It will not be good for you to do…”

ExpressionMeaning and General CharacterIf used in a sentence with a first-person subjectIf used in a sentence with a second-person subject
"Ikemasen"It means "it is not allowed".
Used both in spoken and written style
Sounds naturalSounds natural
"Dame desu"It means "no good"
Used in more
casual conversation
Sounds natural only when the speaker asks for permission in a questionSounds natural with family and friends
"Narimasen"It means "it is not allowed".
Used in more formal speech or written style
Sounds natural but more formal than "ikemasen"Gives an awkward impression in most cases. We recommend you not to use it.

However, as for my comments on fine nuances, frequency of use and such, you don’t have to take them at full face value. There may be different ways of feeling about them depending on the area, generation, etc., of the listener.

If you have the chance to travel to different parts of Japan, or watch movies, dramas and interviews, carefully listen for how people speak.

[End of the English post]



1. 「ゆるされない」の三通さんとおりのかた
2. 「いけません」
3. 「だめです」
4. 「なりません」
5. まとめ

1. 「ゆるされない」の三通さんとおりのかた



これはじゅうてい構文こうぶんで、けってきえいの「I must do something」「I need to do something」とおなになります。


2. 「いけません」




れい1 わたしはちまでにごとかないといけません。


れい2 [母親ははおやどもたちに] おみせのものにさわっちゃいけません。

3. 「だめです」



An image to say "ikemasen"
The first word we say to strop a baby from doing something is “dame”.




れい3 わたしはちまでにごとかないとだめです。

れい1はぜんかんじでしたが、れい3をくと、「おくれたらどんなわるいことがきるんだろう? なにえられるんだろうか?」などとえてしまいます。


れい4 [学生がくせい] レポート、明日あしたまでにさなくちゃだめですか?

   [きょう] むずかしかったら、あさってでもいいですよ。


れい5 [母親ははおやどもたちに] あぶない! わたっちゃだめ!

4. 「なりません」



れい6 検閲けんえつはこれをしてはならない。通信つうしんみつは、これをおかしてはならない。(本国憲法第ほんこくけんぽうだい21にじゅういちじょうせつ



れい7 わたしはちまでにしゃかなければなりません。



5. まとめ






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