This sentence is from a grammar website:


Why is という necessary?

What does it add?

And what meaning is lost in writing the sentence without it? For example, as in:



2 Answers 2


In The Structure of the Japanese Language, Susumu Kuno's treatment of こと, , ということ and というの as complementizers separates them into two categories - one involving presupposition and one without.

All the four forms listed above can be used when there is presupposition of truth. But こと and cannot be used when the predicate does not contain presupposition.

I'm going to attempt to summarise some of that here but his analysis is actually much more complete.

Observe this example taken from his book:

[1] It is probable that John hit Mary:

a. ジョンがマリを殴った​{こと・の}はありうることだ。 (Unacceptable)

b. ジョンがマリを殴った​{ということ・というの}はありうることだ。 (Acceptable)

[2] It is false that John hit Mary:

a. ジョンがマリを殴った​{こと・の}は嘘だ。 (Unacceptable)

b. ジョンがマリを殴った​{ということ・というの}は嘘だ。 (Acceptable)

What is observed is that in the 1a and 2a, こと and cannot be used because "is probable" and "is false" indicates that the speaker does not presuppose the event of "John hit Mary" to be true.

I shall not include the complete analysis of こと, and but in summary:

  • こと and assumes that the event is true, while does not.

Also summarising the analysis of こと and :

  • represents a tangible action/state that is directly perceptible (by the five senses), while こと does not and instead represents a more abstract concept.

So in fact there is a slight difference in meaning.


  1. 主人公が犯人だったが一番面白かった。 (主人公が犯人だった is presupposed to be true)

  2. 主人公が犯人だったというのが一番面白かった。 (There is no presupposition) Or (主人公が犯人だった is presupposed to be true)

  • 1
    But in this case, the speaker already knows that 主人公が犯人だった is true, so why is というの needed?
    – dainichi
    Commented Feb 7, 2012 at 2:36
  • @dainichi. My apologies. I just edited my answer. What I meant to say is that というの is less specific than の when it comes to presupposition. の presupposes truth, というの may also presuppose but it can also be without presupposition. So in this instance the difference is very slight.
    – Flaw
    Commented Feb 7, 2012 at 2:54
  • Not by me, if it's me you're asking.
    – dainichi
    Commented Feb 7, 2012 at 6:04
  • @Flaw some people are just mean. i upvoted you anyway. thanks for the long answer and really good book reference. i totally intend to check that book out ASAP.
    – ixtmixilix
    Commented Feb 8, 2012 at 0:30
  • @ixtmixilix. The book's ISBN-13: 978-0262110495. It's a really useful book because it not only explains why some usages are valid, but also goes on to show why some usages are not valid even though you would think that they should be valid by holding all the syntax constant. It's rather pricey if you want to purchase a new one from amazon or ebay though.
    – Flaw
    Commented Feb 8, 2012 at 1:31

It does not change much. I see it like this:

主人公が犯人だったのが一番面白かった。 The main character being actually the killer was the most interesting part.

主人公が犯人だったというのが一番面白かった。 The fact that the main character was actually the killer was the most interesting part.

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