rar5 question about possible asian char

[Dag750]

Hi,

I'm trying to recuperate the password lost on a rar5 archive. It is possible that it is comprised of asian char, such as chinese/japanese/korean

If i'm not mistaken, the buildin charset such as ?a will not comprise such char
I see in https://hashcat.net/wiki/doku.php?id=maskprocessor that it is possible to use custom charset, but i'm not sure how to do it, is it possibe to build a file with all char of say korean, and hashcat will use it as a maskprocessor?

Thanks,