According to 日本語総まとめN1, the grammar for いざ知らず is:

Noun + ならいざ知らず/はいざ知らず

However, I think I've seen it used with verbs too as:

Verb + ならいざ知らず

Is this possible? If so, what about using it with other conditionals such as ば and たら? Could anyone provide examples, please?

Many thanks!

  • To me, it doesn't even make sense with a verb. いざ知らず roughly translates to I don't know about ~, but.... So I don't know about eat/go/whatever verb, but... doesn't even seem meaningful.
    – istrasci
    Commented Jun 21, 2018 at 22:58

1 Answer 1


I don't see any reason that it can't be used with a verb, as long as the verb is followed by の:

Verb + の + ならいざ知らず

If you do a search on Google for ”するのならいざ知らず” you'll find a very small number of hits, so it doesn't seem to be very common. However, one of the hits is an article on Asahi.com so it seems likely to be proper grammar.

The specific sentence is this:



As there was still some doubt about this I'd like to point out that the phrase 。。。いざ知らず means something like the below: (reference)


So I think the important thing here is いざ知らず, and there isn't necessarily set word(s) that must fall before it.

To give a simpler example of using a verb with this, consider this phrase:


This would translate roughly to "I don't know whether you can do that type of thing..."

I don't think there is too much limit on what can go before いざ知らず, though it must be grammatically sound. For example, "するいざ知らず" would be awkward and improper grammar. But as long as there is a の after the verb I think it is valid.

  • There are a lot more examples if you do a search for "のならいざ知らず" (with quotes). Commented Jun 22, 2018 at 0:21
  • Thanks @Locksleyu. I've seen it somewhere used with a verb + の like you pointed out but also without it as in お金を持たないならいざ知らず... but I can't seem to find that example in particular nor any other of the like. I'm not quite sure that last one is right, however. Commented Jun 22, 2018 at 19:15
  • If you search for ”しないならいざ知らず” on Google you find a few examples. Here is one: election.ne.jp/10840/archive/201507/1.html?
    – Locksleyu
    Commented Jun 23, 2018 at 2:22
  • Ok. So all we can tell so far is that at least it's being used, although not so often as なら an . I found this at jgram.org: 辞書があるならいざ知らず、何もなくてはこの文章はとても読めるものではない。 Pay special attention to what otenba says in the comments section. According to him, you can even use だったら before いざ知らず but I don't know on what grounds he can assert this. If you don't mind, I'll leave this question open until we find conclusive evidence. Commented Jun 23, 2018 at 13:19
  • I feel you are overthinking this and looking for a higher level pattern that doesn't exist. As long as you understand what いざ知らず means on it's own, there are many diverse things that can come before it and I don't think you need "proof" of a specific pattern. I've added some additional detail to my answer to try and further explain.
    – Locksleyu
    Commented Jun 24, 2018 at 3:56

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