んだ or のです: How to Use Japanese Explanatory Form

んだ (~n da), んです (~n desu) and their variants are primarily used to show emphasis and provide information, but there’s no true English equivalent. Basically, they’re two pieces of Japanese you’ve most likely come across: ん and です. Put them together and you get んです, the ubiquitous expression that’s really hard to translate — but is fairly pretty simple to use. But what does it mean? In a word: nothing. In other words: is.  And when can this grammar point be used? Now, that’s the more important question. Read on to find out the answer. 

Contents

1. How to Make んです

With this grammar point, plain and short forms are your friends. んだ is made out of the particle の, which is a nominalizer, and です and だ. You should use “desu” if you want to make your sentence more formal as “da” is usually used in casual setting.

TenseExampleModification
Present tense verb行くんですVerb + んです
Past tense verb行ったんですVerb ~た + んです
I-adjectives安いんですPlain adjective + んです
I-adjectives (past)安かったんですPast adjective + んです
Noun豚なんですNoun + なんです
Noun (past)豚だったんですNoun + だったんです
Na adjectivesきれいなんですNa adjective +なんです
Na adjectives (past)豚だったんですNa adjective + だったんです

んです is really a shortened form of のです. のです is more polite and formal than んです. んです, depending on the situation, does carry a certain level of formality, but のです is used in writing. At the same time, んだ is an even more casual form of んです. 

  • Very casual: 行くんだ
  • Somewhat casual: 行くんです 
  • Formal/Written: 行くのです

Uses of んです

1. Emphasizing feelings

As mentioned earlier, んです doesn’t really mean anything. There is no one-word translation for it. It functions to color the meaning of an entire statement. One way in which it often does this is by emphasizing the feelings of the speaker. It transforms plain facts into pockets of emotion. 

For example, let’s take strawberries, which are rarely cheap in Japan. They can be pink, white, plump, and sweet, but almost never cheap. If you come across this, you can say:

昨日苺が安かったんです
Kinou ichigo ga yasukattan desu.
The strawberry yesterday was very cheap

How do you think I’m feeling? The んです tells you that you’re emphasizing the “cheapness” of strawbery. Without it, we’d have a bland, 昨日苺が安かったです.  

Another example: Your home country’s team is slated to play Japan in the FIFA World Cup. You know it’s going to be tough deciding who to cheer for. You might say to everybody who asks you about it:

難しいんですね.
Muzukashiin desu ne.
It’s tough, right.

Again, if you just say, 難しいです, it’s flat and even a little robotic, given the football fever and all, but the んです shows that you feel like you have an utter conundrum on your hands. 

2. Seeking an Explanation or Reason

One important nuance of this grammar point is that it either asks about or fills an information gap, in a complementary kind of way. It is often used in questions. The question is already a question but んです complements that by highlighting the absence of some bit of information.  

何をしていいますか。
Nani o shiteimasuka.
What are you doing?

Let’s take a look at how we use “~n desu” for this question.

何をしているんですか。
Nani o shiteirun desu ka.

Both sentences are asking the same thing: what are you doing at the moment? The second one indicates more that there is an information gap, something the speaker doesn’t know. In addition, using んです adds a more conversational tone. 

For example, you’re visiting a friend’s house. You see them crouching down suddenly. There’s an information gap present: you see something weird and random that you don’t know. The question, “What are you doing?” helps them fill in this blank for you.

どうして日本に来ましたか。
Doushite nihon ni kimashitka

どうして日本に来たんですか。
Doushite nihon ni kita ndesuka

You’ve either gotten this question a lot or will, once you’ve cleared security. The first is quite straightforward, and it is quite possible that the question will be put to you this way. But the second is sprinkled with a bit more 知りたいsauce. 

3. Giving information/explanation

This use is also tied to the information gap nuance of this grammar point. In the same way that んです is used in asking questions, it is used in the responses, or in statements providing some information previously unknown to the listener. 

Without んだ, your sentence conveys a piece of information at face value, which can sound like a random statement. んだ, on the other hand, creates a smooth flow by making it clear that you are explaining something. For example:

何をしているんですか。
Nani wo shiteirun desuka?
What are you doing?

「んです」の使い方を勉強しているんですよ。
Ndesu no tsukaikata wo benkyoushiteirun desu yo.
I’m studying the “n desu”.

Let’s take a look at other examples. This form is also used to provide an explanation in situations where someone might be surprised by something that happens or something that another person says or does. 

Q: どうして日本に来たんですか。
Doushite nihon ni kitan desu ka?
Why did you come to Japan?

A: おいしいお寿司を食べたかったんです。
Oishii osushi o tabetakattan desu.
I wanted to eat sushi.

Let’s say while working as an English teacher, you offer to help with the judo club. The teacher in charge gives you a look loaded with at least a million question marks. You quickly explain yourself.

実は、10年前から柔道をやっているんです。
Jitsu wa juunenmaekara juudou o yatteiru ndesu.
Actually, I’ve been practicing judo for ten years.

Relieved, the teacher says:

なるほど、10年前から柔道をやっているんですね。
Naru hodo, juunen mae kara juudou o yatte irun desu ne.
Oh, I see, you’ve been practicing judo for ten years.

This brings us to the next use of this grammar point. 

4. Interpreting or confirming what someone says

As seen in the judo example above, one way of using んです to interpret or confirm is just to repeat what the other person says. This can also be done by paraphrasing what the person says. 

Example

Let’s say you go out in a T-shirt one day in winter. Your friend might immediately be perplexed by this fashion choice. 

A: どうしてTシャツ着ているんですか.
Doushite T shatsu kiteirun desuka.
Why are you wearing a T-shirt?

B: 暑いんですよ.
Atsuin desu yo.
It’s hot.

A: へえ、さむくないんですね。   
Hee, samukunain desu ne.
I see, you’re not cold!

5. Making requests

As it is a semi-casual, semi-polite form, んです can be used when making a variety of requests. This includes anything from asking your coworker for a favor to making doctor’s appointments. Basically, you can use んだ as a way of starting a conversation by sharing the context first.

この資料を確認してほしいんですが.
Kono shiryou o kakunin shite hoshiin desuga.
I want to confirm these documents.

予約がしたいんですが.
Yoyaku ga shitain desu ga.
I want to make a reservation.

As you can see, both statements end in んですが. It is common for sentences making requests to end in が.

This form is also used to make requests in a more indirect way. Let’s say you are at work again, and you want your worker to check a presentation you’ve prepared. You might say: 

あの、プレゼンを作ってみたんですが。
Ano, purezen wo tsukutte mitan desuga.

From this statement alone your colleague will know that you are asking them to check it or look it over for you. You may or may not follow this up with a direct request sentence. 

Conclusion

To recap, usingんです is a quick way to make your Japanese sound more natural. You can add it to the plain and short form or verbs and i-adjectives. With nouns and na-adjectives, you need to add なbefore んです. This Japanese grammar point can be used to emphasize feelings, seek information, give reasons, interpret what someone says or make requests.

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Read more about our JLPT grammar guides!

Are there any similar grammar points to んです?

In terms of giving an explanation or a reason for something, this grammar point is similar
to から. But in sentences using んです, there’s no need to includeから, and vice versa.
Example: A:どうしてTシャツ着ているんですか。B:暑いからです。

What level of the Japanese Language Proficiency Test is んです?

This is N4/N5 grammar. Still, it might take a fair amount of practice and exposure to
natural Japanese to pick up on the nuances of this grammar point. It might take a bit more
to start using it yourself.

What is the level of formality of the Japanese grammar んです?

This is kind of semi-polite. It can be used verbally in a range of situations or in casual
written communication. In writing, のです is used.

Where can examples of this grammar point be found?

Because this is so conversational, pop culture is a good place. For example, there’s a line
in this Hikaru Utada song that uses んです. Try to she see if you can find the line, and
pinpoint the nuance.


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