I'm reading a book and I came across a usage of のだから I couldn't really understand.
The whole sentence is:


My translation to it was : "It has been said that on top of that, about 100 levels are accumulating (on top of each other), and therefore, its vast size is unimaginable". Obviously this is not a literal translation.

What I don't get is the role that のだから plays in this case.
I'd say it has a nuance of cause/result, but then why ので・から were not used in this case?

According to the "best" answer in this question, のだから has 2 rules:

  1. Used when both the speaker and listener know some fact, but expresses a strong feeling on the part of the speaker that the listener, although conscious of said fact, does not fully appreciate its implications.
  2. The clause following ~のだから often expresses the speaker's judgment, intent, wish, or request.

I know for sure that rule (1) is not true in this case, since the fact given in the first part of the sentence was never previously mentioned in the book.

As for (2), I'm still not sure whether the part that comes after のだから can be counted as a "judgment"...

Hopefully someone can help me grasp the idea of のだから!
Thanks in advance!

I'd also appreciate even a list of all of the variations の・ん+です・だ, so I could at least research them myself as I always tend to get confused with them... a link or a short summary of them would be even better but it's really too much of me to ask!

Also, if you want to know, the sentence above was taken from the book ソードアート・オンライン1-アインクラッド。

3 Answers 3


I interpret the の in your example as a nominalizer and shows that this clause is explaining something else in the text. 「なんで腹が痛いか?」「アイスを食べすぎたのだ」.

It's the difference between saying:
"Additionally, it's said about 100 layers have accumulated, so (から) its vast bulk is unimaginably large."
"Additionally, because it's said that about 100 layers have accumulated, its vast bulk is unimaginably large."

Sometimes, の is just a nominalizer, but it seems to me that if you find it near the end of a sentence, it's going to connote either asking for explanation (腹が痛いの?) or providing one (アイスを食べすぎたのだ).

Edit: I feel silly for having answered this a year later, but it was near the top of the list when I checked and I didn't think to look at the date stamp until I posted. Alas.

  • There's nothing wrong with answering old questions :-) Unlike some forums, where "bumping old threads" is discouraged, on Stack Exchange old questions without upvoted answers are automatically bumped to the top of the list every now and then. That's probably why it was near the top. See: Why do people answer old questions?
    – user1478
    Commented Feb 3, 2014 at 18:18
  • Hi William - Thanks for answering! Actually, I have been learning and improving since then and I now understand it the same way. I should have answered it for the sake of other people with the same question in mind, but I wasn't really active this whole time. Anyways - thanks!
    – xTCx
    Commented Feb 3, 2014 at 19:57
  • 1
    それでは「その上に無慮百に及ぶ階層が積み重なっているというので 、茫漠とした広大さは想像を絶する。」と言うのと同じってことになっちゃうじゃないですか。「~というのだから」のニュアンスが全然説明されていません。
    – chocolate
    Commented Feb 15, 2016 at 8:06

As a native Japanese speaker, I do not find a grammatical parsing of 「のだから」 or 「というのだから」 to be of much value or help to understanding its role in this particular sentence because it is being used as a set phrase.

「A + というのだから + B.」 expresses:

"Since they say A, (which was unexpected, surprising, etc.), I now must conclude that B."

The 「というのだから」 in this sentence can be replaced with 「というから」 to retain the exact same meaning but with a slight difference in nuance. The latter is used more often than the former. The former sounds more emphatic than the latter.

You will often hear us say things like:



の at the end of a statement expresses emphasis. I believe that the のだ here is simply used that way.

For example:


You could add on to this sentence:


When using から in to express causation you need to precede it with a verb or です or だ. You simply can't grammatically say のから. So the の was added for emphasis and the だ was added to make the sentence grammatically correct.

ので would probably be ok in here I think but ので is more colloquial and expresses less emphasis than のだから. I generally see it used more in spoken or informal language to express thoughts and feelings rather than facts, so I don't generally see it in written Japanese like your example.

  • Thank you. Finally an answer :) Isn't の a feminine emotional emphasis..? I don't think it's the case.. Maybe it's the nominalizing の, or the explanation one... In my "nihonshock.com" Japanese cheatsheet (it's a great one by the way), it says that のだから can't be used with reasons which are not self-evident to the listener.. I have no idea how that works in here but it might help... I know for sure that in no way that writer should or can assume the reader has some previous knowledge...
    – xTCx
    Commented Jan 30, 2013 at 5:35
  • "あの山は大きいのだから 、登るのが大変でしょう" >>「あの山は大きいから 、登るのが大変でしょう。」のほうがいいと思います。
    – chocolate
    Commented Feb 15, 2016 at 7:32
  • どうもありがとうございます。今読みますと、あんまりいい例ではないのが確かですね。私は日本語はほとんど感覚的に使っていますので、文法を説明するのが難しく、これからは日本人に任せて、回答を遠慮しておきます。
    – Ian Lewis
    Commented Feb 18, 2016 at 4:24

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