I later realised my statement was wrong. I did not test all search terms.
I was only testing the folder: search term.

It seems folder: search is always case-sensitive and it doesn't allow wild
cards.
So if I want to find messages in a specific folder, I'll have to spell the
folder name case-sensitively,
and I'll have to either remember the full path or use regex. Is this
understanding correct?
If it is, then I would say it's a bit unexpected and odd.

On Wed, 18 Nov 2020 at 22:28, David Bremner <david@tethera.net> wrote:

> Wenlong Dai <whudwl@gmail.com> writes:
>
> > Based on my usage and testing, it seems to me that all notmuch searches
> are
> > case-sensitive.
> > Is this true?
> > Is there a way to do case-insensitive search?
>
> Most searches (other than boolean prefixes and regex searches) are in
> fact case insensitive. The definition of case is English-centric. Can
> you give an example of a search that is case-sensitive that you are
> expecting to be case insensitive?
>
> d
>
>

-- 
Kind Regards,
Wenlong Dai