Is there a difference (or nuance) or is it just two ways of saying the same thing?

For example, どうして、とぶか? (1) こわいんです。 (2) こわいですから。

Obviously, those are very simple examples. But are there times where you couldn't use one in place of the other to explain "why" you did something (or you did something "because")?


3 Answers 3


「んです」,「んだ」and friends give a nuance of conveying new information or explaining something to someone for the first time.

「からです」etc. is just a reply to some explicit question of why.

For example, something like this conversation might have both with very different meanings/nuances:

さち:dotnetN00b、もう退社してる?[dotnetN00b, you're already leaving work?]

dotnetN00b: ううん。サーティワン行くんだよ。ついてくる? [No, I'm going to Baskin Robin's! Wanna come?]

さち:いきなりどうして? [Whoah, that's out of the blue. Why you going?]

dotnetN00b: サーティワン、マージうまいからだよ!毎日食っちゃってる。ふふん。 ['cause Baskin Robin's is ridiculously good! I go there every day. :P]

Clear as mud?

  • 5
    A message from Captain Nitpick: 退社する is a change-of-state-verb, so 退社してる means either "has left work" or "(habitually/usually) leaves work". In this case you would use 退社する (or better 退社するの?, since it's a question, not a suggestion).
    – dainichi
    Dec 12, 2012 at 7:02
  • dainichi, thanks. :) I will sound less noob-ish at work now.
    – Ncat
    Dec 13, 2012 at 2:39

(1) こわいんです。  means "The thing is... I'm afraid" or "You see... I'm afraid" or just "I'm afraid!" (you'll translate differently, obviously, if the voice tone is different).

(2) こわいですから。 expresses the reason explicitly, "kowai desu" + kara. It's polite (it isn't "kowai kara", kowai has been made polite by desu), but informal (or you would have said "kowai desu node"). It means "Because I'm afraid...". Please note the suspension points; the phrase is left in the air, less assertive and thus it's softer.

(3) こわいからです。 is "kowai kara" + desu, so the reason has been made polite by desu. It means "Because I'm afraid". It's the neutral way to give a reason, the one you learn on textbooks. It sounds polite, but assertive (and usually you want to avoid to be "assertive"), because it ends abruptly and it doesn't leave space for listener's reply or opinion. Also, for the sake of completeness, you can't have (×) "kowai node desu".

My first answer here... I hope I've done everything right, and I hope it helps, obviously^^.

  • I never learned 〜からです in textbooks. The first one I learned was 〜ですから. My beginner courses used "Japanese For Busy People", so anyone else using that will probably not encounter it, unless they've added it to the revised editions.
    – istrasci
    Dec 12, 2012 at 15:36
  • @istrasci then you used a good textbook. I've something like 5 different basic textbook/thematic handbook and none of them use "desu kara". Some of them are italian editions... so they're probably translation of some '70s textbook XD However, I'm pretty sure because I remember clearly that when I was a beginner I heard desu kara in anime very frequently (and never kara desu), so I looked it up in every book I had and nothing. Now I do have a book that presents "polite form + kara", but it's a 上級(!) Dec 12, 2012 at 21:29
  • I personally agree with your point that ので sounds more formal than から, but opinions differ (see japanese.stackexchange.com/questions/4715/…). And every day I hear at the station: 危ないですから黄色い線までおさがり下さい
    – dainichi
    Dec 13, 2012 at 5:14
  • I know, I've always wondered too, how could it be. My wild guess is that is due to the "more causative" nature of kara, while node is softer, when it comes to express a reason. It's also true that node comes from "no de", which means it's/was a te-kei, and te-kei expresses more of a logical (an temporal) connection, than a clear reason (i.e. Aて、B = A and thus B). This should confirm my previous point... but obviously I'm just guessing here. Dec 13, 2012 at 10:30

I am giving a guess here, so feel free to take shots at this. I am assuming that the ん is の acting as a nominalizer. I will translate from literal to natural.

(1) こわいんです。 → こわいのです。

Scariness exists. → (Because) scariness exists. → "'Cuz it's scary." (The "it" here is assumed by me)

の here is a nominalizer, which perhaps we can think of as turning the adjective こわい into a noun= scariness.

(2) こわいですから。

Scary is because. → "Because I am scared." (assuming the subject is "I")

Technically, こわいですから may not be correct, though one does hear it colloquially. It might make more sense to say:

こわいから。or こわいからです。


What is 〜からです and when is it used? How does it differ from 〜ですから and 〜んです?

Take further note that こわい is a tricky word to use here, because it can both describe the state of being frightened or something frightening. (*I am not sure of the validity of this claim :p)

Also, because of the lack of information I, as a reader, have on this conversation, I cannot accurately ascertain the subject or object being described (as would be necessary to accurately translate into English.)

I also think that どうして、とぶか is somewhat unnatural, especially if you wanted to say "Why'd you jump?" However, I am a novice at the Japanese language, so take my opinion with a grain of salt, especially if you found this conversation from a reliable source.

  • 1
    こわいだから is ungrammatical, you probably mean こわいから.
    – dainichi
    Dec 12, 2012 at 7:10
  • @dainichi, thank you. Is it ungrammatical for the same reason that こわいですから。is technically incorrect, or is there another reason. Am I mistaken, or is the exclamation こわいだから! somewhat common colloquially?
    – yadokari
    Dec 12, 2012 at 15:08
  • I was thinking that although から is frowned upon for ending a sentence (?), perhaps だから would be a little different because it is a separate word? for example "大丈夫だから" is somewhat common, is it not?
    – yadokari
    Dec 12, 2012 at 15:11
  • こわい is a 形容詞/iAdjective, so it is basically never followed by a だ (although 形容詞+です is the formula to make a sentence-final 形容詞 polite). For a 名詞/noun like 大丈夫, the +だ is required to end the sentence. What I think is happening in the こわいから example is technically forming a dependent clause, then eliding(?) the main part of the sentence.
    – jkerian
    Dec 12, 2012 at 15:56
  • 1
    I think it might exist in some dialects, but in standard Japanese, it is ungrammatical regardless of formality. Unless it's こわい、だから[...] which is something else.
    – dainichi
    Dec 13, 2012 at 5:04

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